Stream files from store instead of buffering them

When an artifact is requested from hydra the output is first copied from the nix store into memory and then sent as a response, delaying the download and taking up significant amounts of memory. As reported in https://github.com/NixOS/hydra/issues/1357 Instead of calling a command and blocking while reading in the entire output, this adds read_into_socket(). the function takes a command, starting a subprocess with that command, returning a file descriptor attached to stdout. This file descriptor is then by responsebuilder of Catalyst to steam the output directly
2024-08-03 14:30:38 +02:00
42 changed files with 475 additions and 427 deletions
--- a/.clang-tidy
+++ b/.clang-tidy
@ -1,12 +0,0 @@
-UseColor: true
-Checks:
-  - -*
-
-  - bugprone-*
-    # kind of nonsense
-  - -bugprone-easily-swappable-parameters
-    # many warnings due to not recognizing `assert` properly
-  - -bugprone-unchecked-optional-access
-
-  - modernize-*
-  - -modernize-use-trailing-return-type
--- a/.envrc
+++ b/.envrc
@ -1 +0,0 @@
-use flake .#clang
--- a/.github/ISSUE_TEMPLATE/bug_report.md
+++ b/.github/ISSUE_TEMPLATE/bug_report.md
@ -0,0 +1,37 @@
+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: bug
+assignees: ''
+
+---
+
+**Describe the bug**
+A clear and concise description of what the bug is.
+
+**To Reproduce**
+Steps to reproduce the behavior:
+1. Go to '...'
+2. Click on '....'
+3. Scroll down to '....'
+4. See error
+
+**Expected behavior**
+A clear and concise description of what you expected to happen.
+
+**Screenshots**
+If applicable, add screenshots to help explain your problem.
+
+**Hydra Server:**
+
+Please fill out this data as well as you can, but don't worry if you can't -- just do your best.
+
+- OS and version: [e.g. NixOS 22.05.20211203.ee3794c]
+- Version of Hydra
+- Version of Nix Hydra is built against
+- Version of the Nix daemon 
+
+
+**Additional context**
+Add any other context about the problem here.
--- a/.github/ISSUE_TEMPLATE/feature_request.md
+++ b/.github/ISSUE_TEMPLATE/feature_request.md
@ -0,0 +1,20 @@
+---
+name: Feature request
+about: Suggest an idea for this project
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+**Is your feature request related to a problem? Please describe.**
+A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
+
+**Describe the solution you'd like**
+A clear and concise description of what you want to happen.
+
+**Describe alternatives you've considered**
+A clear and concise description of any alternative solutions or features you've considered.
+
+**Additional context**
+Add any other context or screenshots about the feature request here.
--- a/.github/dependabot.yml
+++ b/.github/dependabot.yml
@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@ -0,0 +1,14 @@
+name: "Test"
+on:
+  pull_request:
+  push:
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+      with:
+        fetch-depth: 0
+    - uses: cachix/install-nix-action@v17
+    #- run: nix flake check
+    - run: nix-build -A checks.x86_64-linux.build -A checks.x86_64-linux.validate-openapi
--- a/.gitignore
+++ b/.gitignore
@ -5,5 +5,3 @@
 /src/sql/tmp.sqlite
 result
 result-*
-.hydra-data
-outputs
--- a/README.md
+++ b/README.md
@ -78,11 +78,11 @@ $ nix-build
 ### Development Environment

 You can use the provided shell.nix to get a working development environment:
-
 ```
-$ nix develop
-[nix-shell]$ just setup
-[nix-shell]$ just install
+$ nix-shell
+$ autoreconfPhase
+$ configurePhase # NOTE: not ./configure
+$ make
 ```

 ### Executing Hydra During Development
@ -91,9 +91,10 @@ When working on new features or bug fixes you need to be able to run Hydra from
 can be done using [foreman](https://github.com/ddollar/foreman):

 ```
-$ nix develop
-[nix-shell]$ just install
-[nix-shell]$ foreman start
+$ nix-shell
+$ # hack hack
+$ make
+$ foreman start
 ```

 Have a look at the [Procfile](./Procfile) if you want to see how the processes are being started. In order to avoid
@ -114,22 +115,22 @@ Start by following the steps in [Development Environment](#development-environme
 Then, you can run the tests and the perlcritic linter together with:

 ```console
-$ nix develop
-[nix-shell]$ just test
+$ nix-shell
+$ make check
 ```

 You can run a single test with:

 ```
-$ nix develop
-[nix-shell]$ yath test ./t/foo/bar.t
+$ nix-shell
+$ yath test ./t/foo/bar.t
 ```

 And you can run just perlcritic with:

 ```
-$ nix develop
-[nix-shell]$ just perlcritic
+$ nix-shell
+$ make perlcritic
 ```

 ### JSON API
--- a/doc/dev-notes.txt
+++ b/doc/dev-notes.txt
@ -0,0 +1,122 @@
+* Recreating the schema bindings:
+
+  $ make -C src/sql update-dbix
+
+* Running the test server:
+
+  $ DBIC_TRACE=1 ./script/hydra_server.pl
+
+* Setting the maximum number of concurrent builds per system type:
+
+  $ psql -d hydra <<< "insert into SystemTypes(system, maxConcurrent) values('i686-linux', 3);"
+
+* Creating a user:
+
+  $ hydra-create-user root --email-address 'e.dolstra@tudelft.nl' \
+      --password-prompt
+
+  (Replace "foobar" with the desired password.)
+
+  To make the user an admin:
+
+  $ hydra-create-user root --role admin
+
+  To enable a non-admin user to create projects:
+
+  $ hydra-create-user root --role create-projects
+
+* Changing the priority of a scheduled build:
+
+  update buildschedulinginfo set priority = 200 where id = <ID>;
+
+* Changing the priority of all builds for a jobset:
+
+  update buildschedulinginfo set priority = 20 where id in (select id from builds where finished = 0 and project = 'nixpkgs' and jobset = 'trunk');
+  
+
+* Steps to install:
+
+  - Install the Hydra closure.
+
+  - Set HYDRA_DATA to /somewhere.
+  
+  - Run hydra_init.pl
+
+  - Start hydra_server
+
+  - Visit http://localhost:3000/
+
+  - Create a user (see above)
+
+  - Create a project, jobset etc.
+
+  - Start hydra_evaluator and hydra_queue_runner
+
+
+* Job selection:
+  
+    php-sat:build [system = "i686-linux"]
+    php-sat:build [same system]
+    tarball [same patchelfSrc]
+    --if system i686-linux --arg build {...}
+
+
+* Restart all aborted builds in a given evaluation (e.g. 820909):
+
+  > update builds set finished = 0 where id in (select id from builds where finished = 1 and buildstatus = 3 and exists (select 1 from jobsetevalmembers where eval = 820909 and build = id));
+
+
+* Restart all builds in a given evaluation that had a build step time out:
+
+  > update builds set finished = 0 where id in (select id from builds where finished = 1 and buildstatus != 0 and exists (select 1 from jobsetevalmembers where eval = 926992 and build = id) and exists (select 1 from buildsteps where build = id and status = 7));
+
+
+* select * from (select project, jobset, job, system, max(timestamp) timestamp from builds where finished = 1 group by project, jobset, job, system) x join builds y on x.timestamp = y.timestamp and x.project = y.project and x.jobset = y.jobset and x.job = y.job and x.system = y.system;
+
+  select * from (select project, jobset, job, system, max(timestamp) timestamp from builds where finished = 1 group by project, jobset, job, system) natural join builds;
+
+
+* Delete all scheduled builds that are not already building:
+
+  delete from builds where finished = 0 and not exists (select 1 from buildschedulinginfo s where s.id = builds.id and busy != 0);
+
+
+* select x.project, x.jobset, x.job, x.system, x.id, x.timestamp, r.buildstatus, b.id, b.timestamp
+  from (select project, jobset, job, system, max(id) as id from Builds where finished = 1 group by project, jobset, job, system) as a_
+  natural join Builds x
+  natural join BuildResultInfo r
+  left join Builds b on b.id =
+    (select max(id) from builds c
+     natural join buildresultinfo r2
+     where x.project = c.project and x.jobset = c.jobset and x.job = c.job and x.system = c.system
+           and x.id > c.id and r.buildstatus != r2.buildstatus);
+
+* Using PostgreSQL (version 9.2 or newer is required): 
+
+  $ HYDRA_DBI="dbi:Pg:dbname=hydra;" hydra-server
+
+
+* Find the builds with the highest number of build steps:
+
+  select id, (select count(*) from buildsteps where build = x.id) as n from builds x order by n desc;
+
+
+* Evaluating the NixOS Hydra jobs:
+
+  $ ./hydra_eval_jobs ~/Dev/nixos-wc/release.nix --arg nixpkgs '{outPath = /home/eelco/Dev/nixpkgs-wc;}' --arg nixosSrc '{outPath = /home/eelco/Dev/nixos-wc; rev = 1234;}' --arg services '{outhPath = /home/eelco/services-wc;}' --argstr system i686-linux --argstr system x86_64-linux --arg officialRelease false
+
+
+* Show all the failing jobs/systems in the nixpkgs:stdenv jobset that
+  succeed in the nixpkgs:trunk jobset:
+
+  select job, system from builds b natural join buildresultinfo where project = 'nixpkgs' and jobset = 'stdenv' and iscurrent = 1 and finished = 1 and buildstatus != 0 and exists (select 1 from builds natural join buildresultinfo where project = 'nixpkgs' and jobset = 'trunk' and job = b.job and system = b.system and iscurrent = 1 and finished = 1 and buildstatus = 0) order by job, system;
+
+
+* Get all Nixpkgs jobs that have never built succesfully:
+
+  select project, jobset, job from builds b1
+    where project = 'nixpkgs' and jobset = 'trunk' and iscurrent = 1
+    group by project, jobset, job
+    having not exists
+      (select 1 from builds b2 where b1.project = b2.project and b1.jobset = b2.jobset and b1.job = b2.job and finished = 1 and buildstatus = 0)
+    order by project, jobset, job;
--- a/doc/manual/src/hacking.md
+++ b/doc/manual/src/hacking.md
@ -12,14 +12,15 @@ To enter a shell in which all environment variables (such as `PERL5LIB`)
 and dependencies can be found:

 ```console
-$ nix develop
+$ nix-shell
 ```

 To build Hydra, you should then do:

 ```console
-[nix-shell]$ just setup
-[nix-shell]$ just install
+[nix-shell]$ autoreconfPhase
+[nix-shell]$ configurePhase
+[nix-shell]$ make
 ```

 You start a local database, the webserver, and other components with
@ -29,8 +30,6 @@ foreman:
 $ foreman start
 ```

-The Hydra interface will be available on port 63333, with an admin user named "alice" with password "foobar"
-
 You can run just the Hydra web server in your source tree as follows:

 ```console
@ -40,13 +39,18 @@ $ ./src/script/hydra-server
 You can run Hydra's test suite with the following:

 ```console
-[nix-shell]$ just test
+[nix-shell]$ make check
+[nix-shell]$ # to run as many tests as you have cores:
+[nix-shell]$ make check YATH_JOB_COUNT=$NIX_BUILD_CORES
 [nix-shell]$ # or run yath directly:
 [nix-shell]$ yath test
 [nix-shell]$ # to run as many tests as you have cores:
 [nix-shell]$ yath test -j $NIX_BUILD_CORES
 ```

+When using `yath` instead of `make check`, ensure you have run `make`
+in the root of the repository at least once.
+
 **Warning**: Currently, the tests can fail
 if run with high parallelism [due to an issue in
 `Test::PostgreSQL`](https://github.com/TJC/Test-postgresql/issues/40)
@ -97,14 +101,3 @@ Off NixOS, change `/etc/nix/nix.conf`:
 ```conf
 trusted-users = root YOURUSERNAME
 ```
-
-### Updating schema bindings
-
-```
-just update-dbix
-```
-
-### Find the builds with the highest number of build steps:
-
-        select id, (select count(*) from buildsteps where build = x.id) as n from builds x order by n desc;
-
--- a/doc/manual/src/webhooks.md
+++ b/doc/manual/src/webhooks.md
@ -1,12 +1,9 @@
 # Webhooks

-Hydra can be notified by github or gitea with webhooks to trigger a new evaluation when a
+Hydra can be notified by github's webhook to trigger a new evaluation when a
 jobset has a github repo in its input.
-
-## GitHub
-
-To set up a webhook for a GitHub repository go to `https://github.com/<yourhandle>/<yourrepo>/settings`
-and in the `Webhooks` tab click on `Add webhook`.
+To set up a github webhook go to `https://github.com/<yourhandle>/<yourrepo>/settings` and in the `Webhooks` tab
+click on `Add webhook`.

 - In `Payload URL` fill in `https://<your-hydra-domain>/api/push-github`.
 - In `Content type` switch to `application/json`.
@ -14,14 +11,3 @@ and in the `Webhooks` tab click on `Add webhook`.
 - For `Which events would you like to trigger this webhook?` keep the default option for events on `Just the push event.`.

 Then add the hook with `Add webhook`.
-
-## Gitea
-
-To set up a webhook for a Gitea repository go to the settings of the repository in your Gitea instance
-and in the `Webhooks` tab click on `Add Webhook` and choose `Gitea` in the drop down.
-
- In `Target URL` fill in `https://<your-hydra-domain>/api/push-gitea`.
- Keep HTTP method `POST`, POST Content Type `application/json` and Trigger On `Push Events`.
- Change the branch filter to match the git branch hydra builds.
-
-Then add the hook with `Add webhook`.
--- a/flake.lock
+++ b/flake.lock
@ -24,11 +24,11 @@
        ]
      },
      "locked": {
-        "lastModified": 1722555600,
-        "narHash": "sha256-XOQkdLafnb/p9ij77byFQjDf5m5QYl9b2REiVClC+x4=",
+        "lastModified": 1719994518,
+        "narHash": "sha256-pQMhCCHyQGRzdfAkdJ4cIWiw+JNuWsTX7f0ZYSyz0VY=",
        "owner": "hercules-ci",
        "repo": "flake-parts",
-        "rev": "8471fe90ad337a8074e957b69ca4d0089218391d",
+        "rev": "9227223f6d922fee3c7b190b2cc238a99527bbb7",
        "type": "github"
      },
      "original": {
@ -48,11 +48,11 @@
        "pre-commit-hooks": "pre-commit-hooks"
      },
      "locked": {
-        "lastModified": 1728163191,
-        "narHash": "sha256-SW0IEBsPN1EysqzvfDT+8Kimtzy03O1BxQQm7ZB6fRY=",
+        "lastModified": 1721091462,
+        "narHash": "sha256-0cmEeoOiB91BviTJHzIyxkY+Gxv3O8ZnnExVAoXEFGI=",
        "ref": "refs/heads/main",
-        "rev": "ed9b7f4f84fd60ad8618645cc1bae2d686ff0db6",
-        "revCount": 16323,
+        "rev": "6b4d46e9e0e1dd80e0977684ab20d14bcd1a6bc3",
+        "revCount": 15967,
        "type": "git",
        "url": "https://git.lix.systems/lix-project/lix"
      },
@ -74,11 +74,11 @@
        "treefmt-nix": "treefmt-nix"
      },
      "locked": {
-        "lastModified": 1723579251,
-        "narHash": "sha256-xnHtfw0gRhV+2S9U7hQwvp2klTy1Iv7FlMMO0/WiMVc=",
+        "lastModified": 1721195872,
+        "narHash": "sha256-TlvRq634MSl22BWLmpTy2vdtKntbZlsUwdMq8Mp9AWs=",
        "ref": "refs/heads/main",
-        "rev": "42a160bce2fd9ffebc3809746bc80cc7208f9b08",
-        "revCount": 609,
+        "rev": "c057494450f2d1420726ddb0bab145a5ff4ddfdd",
+        "revCount": 608,
        "type": "git",
        "url": "https://git.lix.systems/lix-project/nix-eval-jobs"
      },
@ -111,11 +111,11 @@
    "nix2container": {
      "flake": false,
      "locked": {
-        "lastModified": 1720642556,
-        "narHash": "sha256-qsnqk13UmREKmRT7c8hEnz26X3GFFyIQrqx4EaRc1Is=",
+        "lastModified": 1712990762,
+        "narHash": "sha256-hO9W3w7NcnYeX8u8cleHiSpK2YJo7ecarFTUlbybl7k=",
        "owner": "nlewo",
        "repo": "nix2container",
-        "rev": "3853e5caf9ad24103b13aa6e0e8bcebb47649fe4",
+        "rev": "20aad300c925639d5d6cbe30013c8357ce9f2a2e",
        "type": "github"
      },
      "original": {
@ -126,11 +126,11 @@
    },
    "nixpkgs": {
      "locked": {
-        "lastModified": 1728193676,
-        "narHash": "sha256-PbDWAIjKJdlVg+qQRhzdSor04bAPApDqIv2DofTyynk=",
+        "lastModified": 1720691131,
+        "narHash": "sha256-CWT+KN8aTPyMIx8P303gsVxUnkinIz0a/Cmasz1jyIM=",
        "owner": "NixOS",
        "repo": "nixpkgs",
-        "rev": "ecbc1ca8ffd6aea8372ad16be9ebbb39889e55b6",
+        "rev": "a046c1202e11b62cbede5385ba64908feb7bfac4",
        "type": "github"
      },
      "original": {
@ -159,11 +159,11 @@
    "pre-commit-hooks": {
      "flake": false,
      "locked": {
-        "lastModified": 1721042469,
-        "narHash": "sha256-6FPUl7HVtvRHCCBQne7Ylp4p+dpP3P/OYuzjztZ4s70=",
+        "lastModified": 1712055707,
+        "narHash": "sha256-4XLvuSIDZJGS17xEwSrNuJLL7UjDYKGJSbK1WWX2AK8=",
        "owner": "cachix",
        "repo": "git-hooks.nix",
-        "rev": "f451c19376071a90d8c58ab1a953c6e9840527fd",
+        "rev": "e35aed5fda3cc79f88ed7f1795021e559582093a",
        "type": "github"
      },
      "original": {
@ -187,11 +187,11 @@
        ]
      },
      "locked": {
-        "lastModified": 1723454642,
-        "narHash": "sha256-S0Gvsenh0II7EAaoc9158ZB4vYyuycvMGKGxIbERNAM=",
+        "lastModified": 1721059077,
+        "narHash": "sha256-gCICMMX7VMSKKt99giDDtRLkHJ0cwSgBtDijJAqTlto=",
        "owner": "numtide",
        "repo": "treefmt-nix",
-        "rev": "349de7bc435bdff37785c2466f054ed1766173be",
+        "rev": "0fb28f237f83295b4dd05e342f333b447c097398",
        "type": "github"
      },
      "original": {
--- a/flake.nix
+++ b/flake.nix
@ -73,21 +73,6 @@
        default = pkgsBySystem.${system}.hydra;
      });

-      devShells = forEachSystem (system: let
-        pkgs = pkgsBySystem.${system};
-        lib = pkgs.lib;
-
-        mkDevShell = stdenv: (pkgs.mkShell.override { inherit stdenv; }) {
-          inputsFrom = [ (self.packages.${system}.default.override { inherit stdenv; }) ];
-
-          packages =
-            lib.optional (stdenv.cc.isClang && stdenv.hostPlatform == stdenv.buildPlatform) pkgs.clang-tools;
-        };
-      in {
-        default = mkDevShell pkgs.stdenv;
-        clang = mkDevShell pkgs.clangStdenv;
-      });
-
      nixosModules = import ./nixos-modules {
        overlays = overlayList;
      };
--- a/foreman/start-evaluator.sh
+++ b/foreman/start-evaluator.sh
@ -3,4 +3,4 @@
 # wait for hydra-server to listen
 while ! nc -z localhost 63333; do sleep 1; done

-HYDRA_CONFIG=$(pwd)/.hydra-data/hydra.conf exec $(pwd)/outputs/out/bin/hydra-evaluator
+HYDRA_CONFIG=$(pwd)/.hydra-data/hydra.conf exec hydra-evaluator
--- a/foreman/start-hydra.sh
+++ b/foreman/start-hydra.sh
@ -28,4 +28,4 @@ use-substitutes = true
 </hydra_notify>
 EOF
 fi
-HYDRA_CONFIG=$(pwd)/.hydra-data/hydra.conf exec $(pwd)/outputs/out/bin/hydra-dev-server --port 63333 --restart --debug
+HYDRA_CONFIG=$(pwd)/.hydra-data/hydra.conf exec hydra-dev-server --port 63333 --restart --debug
--- a/foreman/start-notify.sh
+++ b/foreman/start-notify.sh
@ -3,4 +3,4 @@
 # wait for hydra-server to listen
 while ! nc -z localhost 63333; do sleep 1; done

-HYDRA_CONFIG=$(pwd)/.hydra-data/hydra.conf exec $(pwd)/outputs/out/bin/hydra-notify
+HYDRA_CONFIG=$(pwd)/.hydra-data/hydra.conf exec hydra-notify
--- a/foreman/start-queue-runner.sh
+++ b/foreman/start-queue-runner.sh
@ -3,4 +3,4 @@
 # wait until hydra is listening on port 63333
 while ! nc -z localhost 63333; do sleep 1; done

-NIX_REMOTE_SYSTEMS="" HYDRA_CONFIG=$(pwd)/.hydra-data/hydra.conf exec $(pwd)/outputs/out/bin/hydra-queue-runner
+NIX_REMOTE_SYSTEMS="" HYDRA_CONFIG=$(pwd)/.hydra-data/hydra.conf exec hydra-queue-runner
--- a/17
+++ b/17
@ -1,17 +0,0 @@
-setup *OPTIONS:
-    meson setup build --prefix="$PWD/outputs/out" $mesonFlags {{ OPTIONS }}
-
-build *OPTIONS:
-    meson compile -C build {{ OPTIONS }}
-
-install *OPTIONS: (build OPTIONS)
-    meson install -C build
-
-test *OPTIONS:
-    meson test -C build --print-errorlogs {{ OPTIONS }}
-
-update-dbix:
-    cd src/sql && ./update-dbix-harness.sh
-
-perlcritic:
-    perlcritic .
--- a/package.nix
+++ b/package.nix
@ -37,7 +37,6 @@

 , cacert
 , foreman
-, just
 , glibcLocales
 , libressl
 , openldap
@ -191,8 +190,6 @@ stdenv.mkDerivation (finalAttrs: {
    postgresql_13
    pixz
    nix-eval-jobs
-    perlPackages.PLS
-    just
  ];

  checkInputs = [
@ -236,8 +233,8 @@ stdenv.mkDerivation (finalAttrs: {
  shellHook = ''
    pushd $(git rev-parse --show-toplevel) >/dev/null

-    PATH=$(pwd)/outputs/out/bin:$PATH
-    PERL5LIB=$(pwd)/src/lib:$(pwd)/t/lib:$PERL5LIB
+    PATH=$(pwd)/src/hydra-evaluator:$(pwd)/src/script:$(pwd)/src/hydra-queue-runner:$PATH
+    PERL5LIB=$(pwd)/src/lib:$PERL5LIB
    export HYDRA_HOME="$(pwd)/src/"
    mkdir -p .hydra-data
    export HYDRA_DATA="$(pwd)/.hydra-data"
--- a/src/hydra-evaluator/hydra-evaluator.cc
+++ b/src/hydra-evaluator/hydra-evaluator.cc
@ -14,12 +14,11 @@
 #include <sys/wait.h>

 #include <boost/format.hpp>
-#include <utility>

 using namespace nix;
 using boost::format;

-using JobsetName = std::pair<std::string, std::string>;
+typedef std::pair<std::string, std::string> JobsetName;

 class JobsetId {
    public:
@ -29,8 +28,8 @@ class JobsetId {
    int id;


-    JobsetId(std::string  project, std::string  jobset, int id)
-        : project{std::move( project )}, jobset{std::move( jobset )}, id{ id }
+    JobsetId(const std::string & project, const std::string & jobset, int id)
+        : project{ project }, jobset{ jobset }, id{ id }
    {
    }

@ -42,7 +41,7 @@ class JobsetId {
    friend bool operator== (const JobsetId & lhs, const JobsetName & rhs);
    friend bool operator!= (const JobsetId & lhs, const JobsetName & rhs);

-    [[nodiscard]] std::string display() const {
+    std::string display() const {
        return str(format("%1%:%2% (jobset#%3%)") % project % jobset % id);
    }
 };
@ -89,11 +88,11 @@ struct Evaluator
        JobsetId name;
        std::optional<EvaluationStyle> evaluation_style;
        time_t lastCheckedTime, triggerTime;
-        time_t checkInterval;
+        int checkInterval;
        Pid pid;
    };

-    using Jobsets = std::map<JobsetId, Jobset>;
+    typedef std::map<JobsetId, Jobset> Jobsets;

    std::optional<JobsetName> evalOne;

@ -139,15 +138,13 @@ struct Evaluator

            if (evalOne && name != *evalOne) continue;

-            auto res = state->jobsets.try_emplace(name, Jobset{.name=name});
+            auto res = state->jobsets.try_emplace(name, Jobset{name});

            auto & jobset = res.first->second;
            jobset.lastCheckedTime = row["lastCheckedTime"].as<time_t>(0);
            jobset.triggerTime = row["triggerTime"].as<time_t>(notTriggered);
            jobset.checkInterval = row["checkInterval"].as<time_t>();
-
-            int eval_style = row["jobset_enabled"].as<int>(0);
-            switch (eval_style) {
+            switch (row["jobset_enabled"].as<int>(0)) {
                case 1:
                    jobset.evaluation_style = EvaluationStyle::SCHEDULE;
                    break;
@ -157,9 +154,6 @@ struct Evaluator
                case 3:
                    jobset.evaluation_style = EvaluationStyle::ONE_AT_A_TIME;
                    break;
-                default:
-                    // Disabled or unknown. Leave as nullopt.
-                    break;
            }

            seen.insert(name);
@ -181,7 +175,7 @@ struct Evaluator

    void startEval(State & state, Jobset & jobset)
    {
-        time_t now = time(nullptr);
+        time_t now = time(0);

        printInfo("starting evaluation of jobset ‘%s’ (last checked %d s ago)",
            jobset.name.display(),
@ -234,7 +228,7 @@ struct Evaluator
            return false;
        }

-        if (jobset.lastCheckedTime + jobset.checkInterval <= time(nullptr)) {
+        if (jobset.lastCheckedTime + jobset.checkInterval <= time(0)) {
            // Time to schedule a fresh evaluation. If the jobset
            // is a ONE_AT_A_TIME jobset, ensure the previous jobset
            // has no remaining, unfinished work.
@ -307,7 +301,7 @@ struct Evaluator

        /* Put jobsets in order of ascending trigger time, last checked
           time, and name. */
-        std::ranges::sort(sorted,
+        std::sort(sorted.begin(), sorted.end(),
            [](const Jobsets::iterator & a, const Jobsets::iterator & b) {
                return
                    a->second.triggerTime != b->second.triggerTime
@ -330,7 +324,7 @@ struct Evaluator

        while (true) {

-            time_t now = time(nullptr);
+            time_t now = time(0);

            std::chrono::seconds sleepTime = std::chrono::seconds::max();

@ -417,7 +411,7 @@ struct Evaluator
                        printInfo("evaluation of jobset ‘%s’ %s",
                            jobset.name.display(), statusToString(status));

-                        auto now = time(nullptr);
+                        auto now = time(0);

                        jobset.triggerTime = notTriggered;
                        jobset.lastCheckedTime = now;
--- a/src/hydra-queue-runner/build-remote.cc
+++ b/src/hydra-queue-runner/build-remote.cc
@ -1,6 +1,5 @@
 #include <algorithm>
 #include <cmath>
-#include <ranges>

 #include <sys/types.h>
 #include <sys/stat.h>
@ -42,7 +41,6 @@ static Strings extraStoreArgs(std::string & machine)
        }
    } catch (BadURL &) {
        // We just try to continue with `machine->sshName` here for backwards compat.
-        printMsg(lvlWarn, "could not parse machine URL '%s', passing through to SSH", machine);
    }

    return result;
@ -135,8 +133,8 @@ static void copyClosureTo(
    auto sorted = destStore.topoSortPaths(closure);

    StorePathSet missing;
-    for (auto & i : std::ranges::reverse_view(sorted))
-        if (!present.count(i)) missing.insert(i);
+    for (auto i = sorted.rbegin(); i != sorted.rend(); ++i)
+        if (!present.count(*i)) missing.insert(*i);

    printMsg(lvlDebug, "sending %d missing paths", missing.size());

@ -306,12 +304,12 @@ static BuildResult performBuild(

    time_t startTime, stopTime;

-    startTime = time(nullptr);
+    startTime = time(0);
    {
        MaintainCount<counter> mc(nrStepsBuilding);
        result = ServeProto::Serialise<BuildResult>::read(localStore, conn);
    }
-    stopTime = time(nullptr);
+    stopTime = time(0);

    if (!result.startTime) {
        // If the builder gave `startTime = 0`, use our measurements
@ -340,10 +338,10 @@ static BuildResult performBuild(
            // were known
            assert(outputPath);
            auto outputHash = outputHashes.at(outputName);
-            auto drvOutput = DrvOutput { .drvHash=outputHash, .outputName=outputName };
+            auto drvOutput = DrvOutput { outputHash, outputName };
            result.builtOutputs.insert_or_assign(
                std::move(outputName),
-                Realisation { .id=drvOutput, .outPath=*outputPath });
+                Realisation { drvOutput, *outputPath });
        }
    }

@ -370,7 +368,7 @@ static std::map<StorePath, ValidPathInfo> queryPathInfos(
        auto references = ServeProto::Serialise<StorePathSet>::read(localStore, conn);
        readLongLong(conn.from); // download size
        auto narSize = readLongLong(conn.from);
-        auto narHash = Hash::parseAny(readString(conn.from), HashType::SHA256);
+        auto narHash = Hash::parseAny(readString(conn.from), htSHA256);
        auto ca = ContentAddress::parseOpt(readString(conn.from));
        readStrings<StringSet>(conn.from); // sigs
        ValidPathInfo info(localStore.parseStorePath(storePathS), narHash);
@ -399,7 +397,8 @@ static void copyPathFromRemote(
      /* Receive the NAR from the remote and add it to the
          destination store. Meanwhile, extract all the info from the
          NAR that getBuildOutput() needs. */
-      auto coro = [&]() -> WireFormatGenerator {
+      auto source2 = sinkToSource([&](Sink & sink)
+      {
          /* Note: we should only send the command to dump the store
              path to the remote if the NAR is actually going to get read
              by the destination store, which won't happen if this path
@ -410,11 +409,11 @@ static void copyPathFromRemote(
          conn.to << ServeProto::Command::DumpStorePath << localStore.printStorePath(info.path);
          conn.to.flush();

-          co_yield extractNarDataFilter(conn.from, localStore.printStorePath(info.path), narMembers);
-      };
-      GeneratorSource source2{coro()};
+          TeeSource tee(conn.from, sink);
+          extractNarData(tee, localStore.printStorePath(info.path), narMembers);
+      });

-      destStore.addToStore(info, source2, NoRepair, NoCheckSigs);
+      destStore.addToStore(info, *source2, NoRepair, NoCheckSigs);
 }

 static void copyPathsFromRemote(
@ -625,7 +624,6 @@ void State::buildRemote(ref<Store> destStore,
        /* Throttle CPU-bound work. Opportunistically skip updating the current
         * step, since this requires a DB roundtrip. */
        if (!localWorkThrottler.try_acquire()) {
-            MaintainCount<counter> mc(nrStepsWaitingForDownloadSlot);
            updateStep(ssWaitingForLocalSlot);
            localWorkThrottler.acquire();
        }
@ -637,7 +635,7 @@ void State::buildRemote(ref<Store> destStore,
         * copying outputs and we end up building too many things that we
         * haven't been able to allow copy slots for. */
        assert(reservation.unique());
-        reservation = nullptr;
+        reservation = 0;
        wakeDispatcher();

        StorePathSet outputs;
@ -700,7 +698,7 @@ void State::buildRemote(ref<Store> destStore,
        if (info->consecutiveFailures == 0 || info->lastFailure < now - std::chrono::seconds(30)) {
            info->consecutiveFailures = std::min(info->consecutiveFailures + 1, (unsigned int) 4);
            info->lastFailure = now;
-            int delta = static_cast<int>(retryInterval * std::pow(retryBackoff, info->consecutiveFailures - 1) + (rand() % 30));
+            int delta = retryInterval * std::pow(retryBackoff, info->consecutiveFailures - 1) + (rand() % 30);
            printMsg(lvlInfo, "will disable machine ‘%1%’ for %2%s", machine->sshName, delta);
            info->disabledUntil = now + std::chrono::seconds(delta);
        }
--- a/src/hydra-queue-runner/build-result.cc
+++ b/src/hydra-queue-runner/build-result.cc
@ -1,7 +1,6 @@
 #include "hydra-build-result.hh"
 #include "store-api.hh"
 #include "fs-accessor.hh"
-#include "strings.hh"

 #include <regex>

@ -35,8 +34,11 @@ BuildOutput getBuildOutput(
        auto outputS = store->printStorePath(output);
        if (!narMembers.count(outputS)) {
            printInfo("fetching NAR contents of '%s'...", outputS);
-            GeneratorSource source{store->narFromPath(output)};
-            extractNarData(source, outputS, narMembers);
+            auto source = sinkToSource([&](Sink & sink)
+            {
+                sink << store->narFromPath(output);
+            });
+            extractNarData(*source, outputS, narMembers);
        }
    }

--- a/src/hydra-queue-runner/builder.cc
+++ b/src/hydra-queue-runner/builder.cc
@ -1,6 +1,5 @@
 #include <cmath>

-#include "error.hh"
 #include "state.hh"
 #include "hydra-build-result.hh"
 #include "finally.hh"
@ -36,18 +35,10 @@ void State::builder(MachineReservation::ptr reservation)
            activeSteps_.lock()->erase(activeStep);
        });

-        auto conn(dbPool.get());
-
        try {
            auto destStore = getDestStore();
            // Might release the reservation.
-            res = doBuildStep(destStore, reservation, *conn, activeStep);
-        } catch (pqxx::broken_connection & e) {
-            printMsg(lvlError, "db lost while building ‘%s’ on ‘%s’: %s (retriable)",
-                localStore->printStorePath(activeStep->step->drvPath),
-                reservation ? reservation->machine->sshName : std::string("(no machine)"),
-                e.what());
-            conn.markBad();
+            res = doBuildStep(destStore, reservation, activeStep);
        } catch (std::exception & e) {
            printMsg(lvlError, "uncaught exception building ‘%s’ on ‘%s’: %s",
                localStore->printStorePath(activeStep->step->drvPath),
@ -59,7 +50,7 @@ void State::builder(MachineReservation::ptr reservation)
    /* If the machine hasn't been released yet, release and wake up the dispatcher. */
    if (reservation) {
        assert(reservation.unique());
-        reservation = nullptr;
+        reservation = 0;
        wakeDispatcher();
    }

@ -73,7 +64,7 @@ void State::builder(MachineReservation::ptr reservation)
            step_->tries++;
            nrRetries++;
            if (step_->tries > maxNrRetries) maxNrRetries = step_->tries; // yeah yeah, not atomic
-            int delta = static_cast<int>(retryInterval * std::pow(retryBackoff, step_->tries - 1) + (rand() % 10));
+            int delta = retryInterval * std::pow(retryBackoff, step_->tries - 1) + (rand() % 10);
            printMsg(lvlInfo, "will retry ‘%s’ after %ss", localStore->printStorePath(step->drvPath), delta);
            step_->after = std::chrono::system_clock::now() + std::chrono::seconds(delta);
        }
@ -85,7 +76,6 @@ void State::builder(MachineReservation::ptr reservation)

 State::StepResult State::doBuildStep(nix::ref<Store> destStore,
    MachineReservation::ptr & reservation,
-    Connection & conn,
    std::shared_ptr<ActiveStep> activeStep)
 {
    auto step(reservation->step);
@ -116,6 +106,8 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
    buildOptions.maxLogSize = maxLogSize;
    buildOptions.enforceDeterminism = step->isDeterministic;

+    auto conn(dbPool.get());
+
    {
        std::set<Build::ptr> dependents;
        std::set<Step::ptr> steps;
@ -140,7 +132,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
        for (auto build2 : dependents) {
            if (build2->drvPath == step->drvPath) {
                build = build2;
-                pqxx::work txn(conn);
+                pqxx::work txn(*conn);
                notifyBuildStarted(txn, build->id);
                txn.commit();
            }
@ -186,16 +178,16 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
                    unlink(result.logFile.c_str());
                }
            } catch (...) {
-                ignoreExceptionInDestructor();
+                ignoreException();
            }
        }
    });

-    time_t stepStartTime = result.startTime = time(nullptr);
+    time_t stepStartTime = result.startTime = time(0);

    /* If any of the outputs have previously failed, then don't bother
       building again. */
-    if (checkCachedFailure(step, conn))
+    if (checkCachedFailure(step, *conn))
        result.stepStatus = bsCachedFailure;
    else {

@ -203,13 +195,13 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
           building. */
        {
            auto mc = startDbUpdate();
-            pqxx::work txn(conn);
+            pqxx::work txn(*conn);
            stepNr = createBuildStep(txn, result.startTime, buildId, step, machine->sshName, bsBusy);
            txn.commit();
        }

        auto updateStep = [&](StepState stepState) {
-            pqxx::work txn(conn);
+            pqxx::work txn(*conn);
            updateBuildStep(txn, buildId, stepNr, stepState);
            txn.commit();
        };
@ -238,7 +230,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
        }
    }

-    time_t stepStopTime = time(nullptr);
+    time_t stepStopTime = time(0);
    if (!result.stopTime) result.stopTime = stepStopTime;

    /* For standard failures, we don't care about the error
@ -252,7 +244,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
        auto step_(step->state.lock());
        if (!step_->jobsets.empty()) {
            // FIXME: loss of precision.
-            time_t charge = (result.stopTime - result.startTime) / static_cast<time_t>(step_->jobsets.size());
+            time_t charge = (result.stopTime - result.startTime) / step_->jobsets.size();
            for (auto & jobset : step_->jobsets)
                jobset->addStep(result.startTime, charge);
        }
@ -260,7 +252,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,

    /* Finish the step in the database. */
    if (stepNr) {
-        pqxx::work txn(conn);
+        pqxx::work txn(*conn);
        finishBuildStep(txn, result, buildId, stepNr, machine->sshName);
        txn.commit();
    }
@ -336,7 +328,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
            {
                auto mc = startDbUpdate();

-                pqxx::work txn(conn);
+                pqxx::work txn(*conn);

                for (auto & b : direct) {
                    printInfo("marking build %1% as succeeded", b->id);
@ -364,7 +356,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
        /* Send notification about the builds that have this step as
           the top-level. */
        {
-            pqxx::work txn(conn);
+            pqxx::work txn(*conn);
            for (auto id : buildIDs)
                notifyBuildFinished(txn, id, {});
            txn.commit();
@ -393,7 +385,7 @@ State::StepResult State::doBuildStep(nix::ref<Store> destStore,
        }

    } else
-        failStep(conn, step, buildId, result, machine, stepFinished);
+        failStep(*conn, step, buildId, result, machine, stepFinished);

    // FIXME: keep stats about aborted steps?
    nrStepsDone++;
--- a/src/hydra-queue-runner/dispatcher.cc
+++ b/src/hydra-queue-runner/dispatcher.cc
@ -46,7 +46,7 @@ void State::dispatcher()
            auto t_after_work = std::chrono::steady_clock::now();

            prom.dispatcher_time_spent_running.Increment(
-                static_cast<double>(std::chrono::duration_cast<std::chrono::microseconds>(t_after_work - t_before_work).count()));
+                std::chrono::duration_cast<std::chrono::microseconds>(t_after_work - t_before_work).count());
            dispatchTimeMs += std::chrono::duration_cast<std::chrono::milliseconds>(t_after_work - t_before_work).count();

            /* Sleep until we're woken up (either because a runnable build
@ -63,7 +63,7 @@ void State::dispatcher()

            auto t_after_sleep = std::chrono::steady_clock::now();
            prom.dispatcher_time_spent_waiting.Increment(
-                static_cast<double>(std::chrono::duration_cast<std::chrono::microseconds>(t_after_sleep - t_after_work).count()));
+                std::chrono::duration_cast<std::chrono::microseconds>(t_after_sleep - t_after_work).count());

        } catch (std::exception & e) {
            printError("dispatcher: %s", e.what());
@ -190,7 +190,7 @@ system_time State::doDispatch()
        }
    }

-    std::ranges::sort(runnableSorted,
+    sort(runnableSorted.begin(), runnableSorted.end(),
        [](const StepInfo & a, const StepInfo & b)
        {
            return
@ -240,11 +240,11 @@ system_time State::doDispatch()
           - Then by speed factor.

           - Finally by load. */
-        std::ranges::sort(machinesSorted,
+        sort(machinesSorted.begin(), machinesSorted.end(),
            [](const MachineInfo & a, const MachineInfo & b) -> bool
            {
-                float ta = std::round(static_cast<float>(a.currentJobs) / a.machine->speedFactorFloat);
-                float tb = std::round(static_cast<float>(b.currentJobs) / b.machine->speedFactorFloat);
+                float ta = std::round(a.currentJobs / a.machine->speedFactorFloat);
+                float tb = std::round(b.currentJobs / b.machine->speedFactorFloat);
                return
                    ta != tb ? ta < tb :
                    a.machine->speedFactorFloat != b.machine->speedFactorFloat ? a.machine->speedFactorFloat > b.machine->speedFactorFloat :
@ -345,7 +345,7 @@ void State::abortUnsupported()
    auto machines2 = *machines.lock();

    system_time now = std::chrono::system_clock::now();
-    auto now2 = time(nullptr);
+    auto now2 = time(0);

    std::unordered_set<Step::ptr> aborted;

@ -436,7 +436,7 @@ void Jobset::addStep(time_t startTime, time_t duration)

 void Jobset::pruneSteps()
 {
-    time_t now = time(nullptr);
+    time_t now = time(0);
    auto steps_(steps.lock());
    while (!steps_->empty()) {
        auto i = steps_->begin();
@ -464,7 +464,7 @@ State::MachineReservation::~MachineReservation()
    auto prev = machine->state->currentJobs--;
    assert(prev);
    if (prev == 1)
-        machine->state->idleSince = time(nullptr);
+        machine->state->idleSince = time(0);

    {
        auto machineTypes_(state.machineTypes.lock());
--- a/src/hydra-queue-runner/hydra-build-result.hh
+++ b/src/hydra-queue-runner/hydra-build-result.hh
@ -14,7 +14,7 @@ struct BuildProduct
    bool isRegular = false;
    std::optional<nix::Hash> sha256hash;
    std::optional<off_t> fileSize;
-    BuildProduct() = default;
+    BuildProduct() { }
 };

 struct BuildMetric
--- a/src/hydra-queue-runner/hydra-queue-runner.cc
+++ b/src/hydra-queue-runner/hydra-queue-runner.cc
@ -105,7 +105,7 @@ State::State(std::optional<std::string> metricsAddrOpt)
    : config(std::make_unique<HydraConfig>())
    , maxUnsupportedTime(config->getIntOption("max_unsupported_time", 0))
    , dbPool(config->getIntOption("max_db_connections", 128))
-    , localWorkThrottler(static_cast<ptrdiff_t>(config->getIntOption("max_local_worker_threads", std::min(maxSupportedLocalWorkers, std::max(4u, std::thread::hardware_concurrency()) - 2))))
+    , localWorkThrottler(config->getIntOption("max_local_worker_threads", std::min(maxSupportedLocalWorkers, std::max(4u, std::thread::hardware_concurrency()) - 2)))
    , maxOutputSize(config->getIntOption("max_output_size", 2ULL << 30))
    , maxLogSize(config->getIntOption("max_log_size", 64ULL << 20))
    , uploadLogsToBinaryCache(config->getBoolOption("upload_logs_to_binary_cache", false))
@ -138,7 +138,7 @@ nix::MaintainCount<counter> State::startDbUpdate()
 {
    if (nrActiveDbUpdates > 6)
        printError("warning: %d concurrent database updates; PostgreSQL may be stalled", nrActiveDbUpdates.load());
-    return {nrActiveDbUpdates};
+    return MaintainCount<counter>(nrActiveDbUpdates);
 }


@ -171,9 +171,9 @@ void State::parseMachines(const std::string & contents)
        for (auto & f : mandatoryFeatures)
            supportedFeatures.insert(f);

-        using MaxJobs = std::remove_const_t<decltype(nix::Machine::maxJobs)>;
+        using MaxJobs = std::remove_const<decltype(nix::Machine::maxJobs)>::type;

-        auto machine = std::make_shared<::Machine>(::Machine {{
+        auto machine = std::make_shared<::Machine>(nix::Machine {
            // `storeUri`, not yet used
            "",
            // `systemTypes`, not yet used
@ -194,11 +194,11 @@ void State::parseMachines(const std::string & contents)
            tokens[7] != "" && tokens[7] != "-"
                ? base64Decode(tokens[7])
                : "",
-        }});
+        });

        machine->sshName = tokens[0];
        machine->systemTypesSet = tokenizeString<StringSet>(tokens[1], ",");
-        machine->speedFactorFloat = static_cast<float>(atof(tokens[4].c_str()));
+        machine->speedFactorFloat = atof(tokens[4].c_str());

        /* Re-use the State object of the previous machine with the
           same name. */
@ -412,7 +412,7 @@ void State::finishBuildStep(pqxx::work & txn, const RemoteResult & result,
 }


-unsigned int State::createSubstitutionStep(pqxx::work & txn, time_t startTime, time_t stopTime,
+int State::createSubstitutionStep(pqxx::work & txn, time_t startTime, time_t stopTime,
    Build::ptr build, const StorePath & drvPath, const nix::Derivation drv, const std::string & outputName, const StorePath & storePath)
 {
 restart:
@ -534,7 +534,7 @@ void State::markSucceededBuild(pqxx::work & txn, Build::ptr build,
             product.type,
             product.subtype,
             product.fileSize ? std::make_optional(*product.fileSize) : std::nullopt,
-             product.sha256hash ? std::make_optional(product.sha256hash->to_string(Base::Base16, false)) : std::nullopt,
+             product.sha256hash ? std::make_optional(product.sha256hash->to_string(Base16, false)) : std::nullopt,
             product.path,
             product.name,
             product.defaultPath);
@ -594,7 +594,7 @@ std::shared_ptr<PathLocks> State::acquireGlobalLock()
    createDirs(dirOf(lockPath));

    auto lock = std::make_shared<PathLocks>();
-    if (!lock->lockPaths(PathSet({lockPath}), "", false)) return nullptr;
+    if (!lock->lockPaths(PathSet({lockPath}), "", false)) return 0;

    return lock;
 }
@ -602,10 +602,10 @@ std::shared_ptr<PathLocks> State::acquireGlobalLock()

 void State::dumpStatus(Connection & conn)
 {
-    time_t now = time(nullptr);
+    time_t now = time(0);
    json statusJson = {
        {"status", "up"},
-        {"time", time(nullptr)},
+        {"time", time(0)},
        {"uptime", now - startedAt},
        {"pid", getpid()},

@ -613,7 +613,6 @@ void State::dumpStatus(Connection & conn)
        {"nrActiveSteps", activeSteps_.lock()->size()},
        {"nrStepsBuilding", nrStepsBuilding.load()},
        {"nrStepsCopyingTo", nrStepsCopyingTo.load()},
-        {"nrStepsWaitingForDownloadSlot", nrStepsWaitingForDownloadSlot.load()},
        {"nrStepsCopyingFrom", nrStepsCopyingFrom.load()},
        {"nrStepsWaiting", nrStepsWaiting.load()},
        {"nrUnsupportedSteps", nrUnsupportedSteps.load()},
@ -621,7 +620,7 @@ void State::dumpStatus(Connection & conn)
        {"bytesReceived", bytesReceived.load()},
        {"nrBuildsRead", nrBuildsRead.load()},
        {"buildReadTimeMs", buildReadTimeMs.load()},
-        {"buildReadTimeAvgMs", nrBuildsRead == 0 ? 0.0 : (float) buildReadTimeMs / (float) nrBuildsRead},
+        {"buildReadTimeAvgMs", nrBuildsRead == 0 ? 0.0 : (float) buildReadTimeMs / nrBuildsRead},
        {"nrBuildsDone", nrBuildsDone.load()},
        {"nrStepsStarted", nrStepsStarted.load()},
        {"nrStepsDone", nrStepsDone.load()},
@ -630,7 +629,7 @@ void State::dumpStatus(Connection & conn)
        {"nrQueueWakeups", nrQueueWakeups.load()},
        {"nrDispatcherWakeups", nrDispatcherWakeups.load()},
        {"dispatchTimeMs", dispatchTimeMs.load()},
-        {"dispatchTimeAvgMs", nrDispatcherWakeups == 0 ? 0.0 : (float) dispatchTimeMs / (float) nrDispatcherWakeups},
+        {"dispatchTimeAvgMs", nrDispatcherWakeups == 0 ? 0.0 : (float) dispatchTimeMs / nrDispatcherWakeups},
        {"nrDbConnections", dbPool.count()},
        {"nrActiveDbUpdates", nrActiveDbUpdates.load()},
    };
@ -650,8 +649,8 @@ void State::dumpStatus(Connection & conn)
        if (nrStepsDone) {
            statusJson["totalStepTime"] = totalStepTime.load();
            statusJson["totalStepBuildTime"] = totalStepBuildTime.load();
-            statusJson["avgStepTime"] = (float) totalStepTime / (float) nrStepsDone;
-            statusJson["avgStepBuildTime"] = (float) totalStepBuildTime / (float) nrStepsDone;
+            statusJson["avgStepTime"] = (float) totalStepTime / nrStepsDone;
+            statusJson["avgStepBuildTime"] = (float) totalStepBuildTime / nrStepsDone;
        }

        {
@ -678,8 +677,8 @@ void State::dumpStatus(Connection & conn)
                if (m->state->nrStepsDone) {
                    machine["totalStepTime"] = s->totalStepTime.load();
                    machine["totalStepBuildTime"] = s->totalStepBuildTime.load();
-                    machine["avgStepTime"] = (float) s->totalStepTime / (float) s->nrStepsDone;
-                    machine["avgStepBuildTime"] = (float) s->totalStepBuildTime / (float) s->nrStepsDone;
+                    machine["avgStepTime"] = (float) s->totalStepTime / s->nrStepsDone;
+                    machine["avgStepBuildTime"] = (float) s->totalStepBuildTime / s->nrStepsDone;
                }
                statusJson["machines"][m->sshName] = machine;
            }
@ -707,7 +706,7 @@ void State::dumpStatus(Connection & conn)
                };
                if (i.second.runnable > 0)
                    machineTypeJson["waitTime"] = i.second.waitTime.count() +
-                        i.second.runnable * (time(nullptr) - lastDispatcherCheck);
+                        i.second.runnable * (time(0) - lastDispatcherCheck);
                if (i.second.running == 0)
                    machineTypeJson["lastActive"] = std::chrono::system_clock::to_time_t(i.second.lastActive);
            }
@ -733,11 +732,11 @@ void State::dumpStatus(Connection & conn)
            {"narWriteCompressionTimeMs", stats.narWriteCompressionTimeMs.load()},
            {"narCompressionSavings",
             stats.narWriteBytes
-             ? 1.0 - (double) stats.narWriteCompressedBytes / (double) stats.narWriteBytes
+             ? 1.0 - (double) stats.narWriteCompressedBytes / stats.narWriteBytes
             : 0.0},
            {"narCompressionSpeed", // MiB/s
            stats.narWriteCompressionTimeMs
-            ? (double) stats.narWriteBytes / (double) stats.narWriteCompressionTimeMs * 1000.0 / (1024.0 * 1024.0)
+            ? (double) stats.narWriteBytes / stats.narWriteCompressionTimeMs * 1000.0 / (1024.0 * 1024.0)
            : 0.0},
        };

@ -750,20 +749,20 @@ void State::dumpStatus(Connection & conn)
                {"putTimeMs", s3Stats.putTimeMs.load()},
                {"putSpeed",
                 s3Stats.putTimeMs
-                 ? (double) s3Stats.putBytes / (double) s3Stats.putTimeMs * 1000.0 / (1024.0 * 1024.0)
+                 ? (double) s3Stats.putBytes / s3Stats.putTimeMs * 1000.0 / (1024.0 * 1024.0)
                 : 0.0},
                {"get", s3Stats.get.load()},
                {"getBytes", s3Stats.getBytes.load()},
                {"getTimeMs", s3Stats.getTimeMs.load()},
                {"getSpeed",
                 s3Stats.getTimeMs
-                 ? (double) s3Stats.getBytes / (double) s3Stats.getTimeMs * 1000.0 / (1024.0 * 1024.0)
+                 ? (double) s3Stats.getBytes / s3Stats.getTimeMs * 1000.0 / (1024.0 * 1024.0)
                 : 0.0},
                {"head", s3Stats.head.load()},
                {"costDollarApprox",
-                        (double) (s3Stats.get + s3Stats.head) / 10000.0 * 0.004
-                        + (double) s3Stats.put / 1000.0 * 0.005 +
-                        + (double) s3Stats.getBytes / (1024.0 * 1024.0 * 1024.0) * 0.09},
+                        (s3Stats.get + s3Stats.head) / 10000.0 * 0.004
+                        + s3Stats.put / 1000.0 * 0.005 +
+                        + s3Stats.getBytes / (1024.0 * 1024.0 * 1024.0) * 0.09},
            };
        }
    }
@ -849,7 +848,7 @@ void State::run(BuildID buildOne)
    /* Can't be bothered to shut down cleanly. Goodbye! */
    auto callback = createInterruptCallback([&]() { std::_Exit(0); });

-    startedAt = time(nullptr);
+    startedAt = time(0);
    this->buildOne = buildOne;

    auto lock = acquireGlobalLock();
--- a/src/hydra-queue-runner/nar-extractor.cc
+++ b/src/hydra-queue-runner/nar-extractor.cc
@ -3,41 +3,11 @@
 #include "archive.hh"

 #include <unordered_set>
-#include <utility>

 using namespace nix;

-struct Extractor : NARParseVisitor
+struct Extractor : ParseSink
 {
-    class MyFileHandle : public FileHandle
-    {
-        NarMemberData & memberData;
-        uint64_t expectedSize;
-        std::unique_ptr<HashSink> hashSink;
-
-        public:
-            MyFileHandle(NarMemberData & memberData, uint64_t size) : memberData(memberData), expectedSize(size)
-            {
-                hashSink = std::make_unique<HashSink>(HashType::SHA256);
-            }
-
-            void receiveContents(std::string_view data) override
-            {
-                *memberData.fileSize += data.size();
-                (*hashSink)(data);
-                if (memberData.contents) {
-                    memberData.contents->append(data);
-                }
-                assert(memberData.fileSize <= expectedSize);
-                if (memberData.fileSize == expectedSize) {
-                    auto [hash, len] = hashSink->finish();
-                    assert(memberData.fileSize == len);
-                    memberData.sha256 = hash;
-                    hashSink.reset();
-                }
-            }
-    };
-
    std::unordered_set<Path> filesToKeep {
        "/nix-support/hydra-build-products",
        "/nix-support/hydra-release-name",
@ -45,10 +15,11 @@ struct Extractor : NARParseVisitor
    };

    NarMemberDatas & members;
+    NarMemberData * curMember = nullptr;
    Path prefix;

-    Extractor(NarMemberDatas & members, Path  prefix)
-        : members(members), prefix(std::move(prefix))
+    Extractor(NarMemberDatas & members, const Path & prefix)
+        : members(members), prefix(prefix)
    { }

    void createDirectory(const Path & path) override
@ -56,15 +27,41 @@ struct Extractor : NARParseVisitor
        members.insert_or_assign(prefix + path, NarMemberData { .type = FSAccessor::Type::tDirectory });
    }

-    std::unique_ptr<FileHandle> createRegularFile(const Path & path, uint64_t size, bool executable) override
+    void createRegularFile(const Path & path) override
    {
-        auto memberData = &members.insert_or_assign(prefix + path, NarMemberData {
+        curMember = &members.insert_or_assign(prefix + path, NarMemberData {
            .type = FSAccessor::Type::tRegular,
            .fileSize = 0,
            .contents = filesToKeep.count(path) ? std::optional("") : std::nullopt,
        }).first->second;
+    }

-        return std::make_unique<MyFileHandle>(*memberData, size);
+    std::optional<uint64_t> expectedSize;
+    std::unique_ptr<HashSink> hashSink;
+
+    void preallocateContents(uint64_t size) override
+    {
+        expectedSize = size;
+        hashSink = std::make_unique<HashSink>(htSHA256);
+    }
+
+    void receiveContents(std::string_view data) override
+    {
+        assert(expectedSize);
+        assert(curMember);
+        assert(hashSink);
+        *curMember->fileSize += data.size();
+        (*hashSink)(data);
+        if (curMember->contents) {
+            curMember->contents->append(data);
+        }
+        assert(curMember->fileSize <= expectedSize);
+        if (curMember->fileSize == expectedSize) {
+            auto [hash, len] = hashSink->finish();
+            assert(curMember->fileSize == len);
+            curMember->sha256 = hash;
+            hashSink.reset();
+        }
    }

    void createSymlink(const Path & path, const std::string & target) override
@ -79,19 +76,7 @@ void extractNarData(
    const Path & prefix,
    NarMemberDatas & members)
 {
-    auto parser = extractNarDataFilter(source, prefix, members);
-    while (parser.next()) {
-        // ignore raw data
-    }
-}
-
-nix::WireFormatGenerator extractNarDataFilter(
-    Source & source,
-    const Path & prefix,
-    NarMemberDatas & members)
-{
-    return [](Source & source, const Path & prefix, NarMemberDatas & members) -> WireFormatGenerator {
-        Extractor extractor(members, prefix);
-        co_yield parseAndCopyDump(extractor, source);
-    }(source, prefix, members);
+    Extractor extractor(members, prefix);
+    parseDump(extractor, source);
+    // Note: this point may not be reached if we're in a coroutine.
 }
--- a/src/hydra-queue-runner/nar-extractor.hh
+++ b/src/hydra-queue-runner/nar-extractor.hh
@ -13,7 +13,7 @@ struct NarMemberData
    std::optional<nix::Hash> sha256;
 };

-using NarMemberDatas = std::map<nix::Path, NarMemberData>;
+typedef std::map<nix::Path, NarMemberData> NarMemberDatas;

 /* Read a NAR from a source and get to some info about every file
   inside the NAR. */
@ -21,8 +21,3 @@ void extractNarData(
    nix::Source & source,
    const nix::Path & prefix,
    NarMemberDatas & members);
-
-nix::WireFormatGenerator extractNarDataFilter(
-    nix::Source & source,
-    const nix::Path & prefix,
-    NarMemberDatas & members);
--- a/src/hydra-queue-runner/queue-monitor.cc
+++ b/src/hydra-queue-runner/queue-monitor.cc
@ -4,8 +4,7 @@
 #include "thread-pool.hh"

 #include <cstring>
-#include <utility>
-#include <csignal>
+#include <signal.h>

 using namespace nix;

@ -53,7 +52,7 @@ void State::queueMonitorLoop(Connection & conn)
        auto t_after_work = std::chrono::steady_clock::now();

        prom.queue_monitor_time_spent_running.Increment(
-            static_cast<double>(std::chrono::duration_cast<std::chrono::microseconds>(t_after_work - t_before_work).count()));
+            std::chrono::duration_cast<std::chrono::microseconds>(t_after_work - t_before_work).count());

        /* Sleep until we get notification from the database about an
           event. */
@ -80,7 +79,7 @@ void State::queueMonitorLoop(Connection & conn)

        auto t_after_sleep = std::chrono::steady_clock::now();
        prom.queue_monitor_time_spent_waiting.Increment(
-            static_cast<double>(std::chrono::duration_cast<std::chrono::microseconds>(t_after_sleep - t_after_work).count()));
+            std::chrono::duration_cast<std::chrono::microseconds>(t_after_sleep - t_after_work).count());
    }

    exit(0);
@ -89,7 +88,7 @@ void State::queueMonitorLoop(Connection & conn)

 struct PreviousFailure : public std::exception {
    Step::ptr step;
-    PreviousFailure(Step::ptr step) : step(std::move(step)) { }
+    PreviousFailure(Step::ptr step) : step(step) { }
 };


@ -118,7 +117,7 @@ bool State::getQueuedBuilds(Connection & conn,

        for (auto const & row : res) {
            auto builds_(builds.lock());
-            auto id = row["id"].as<BuildID>();
+            BuildID id = row["id"].as<BuildID>();
            if (buildOne && id != buildOne) continue;
            if (builds_->count(id)) continue;

@ -138,7 +137,7 @@ bool State::getQueuedBuilds(Connection & conn,

            newIDs.push_back(id);
            newBuildsByID[id] = build;
-            newBuildsByPath.emplace(build->drvPath, id);
+            newBuildsByPath.emplace(std::make_pair(build->drvPath, id));
        }
    }

@ -163,7 +162,7 @@ bool State::getQueuedBuilds(Connection & conn,
                    ("update Builds set finished = 1, buildStatus = $2, startTime = $3, stopTime = $3 where id = $1 and finished = 0",
                     build->id,
                     (int) bsAborted,
-                     time(nullptr));
+                     time(0));
                txn.commit();
                build->finishedInDB = true;
                nrBuildsDone++;
@ -177,7 +176,7 @@ bool State::getQueuedBuilds(Connection & conn,
        /* Create steps for this derivation and its dependencies. */
        try {
            step = createStep(destStore, conn, build, build->drvPath,
-                build, nullptr, finishedDrvs, newSteps, newRunnable);
+                build, 0, finishedDrvs, newSteps, newRunnable);
        } catch (PreviousFailure & ex) {

            /* Some step previously failed, so mark the build as
@ -222,7 +221,7 @@ bool State::getQueuedBuilds(Connection & conn,
                     "where id = $1 and finished = 0",
                     build->id,
                     (int) (ex.step->drvPath == build->drvPath ? bsFailed : bsDepFailed),
-                     time(nullptr));
+                     time(0));
                notifyBuildFinished(txn, build->id, {});
                txn.commit();
                build->finishedInDB = true;
@ -255,7 +254,7 @@ bool State::getQueuedBuilds(Connection & conn,
            {
            auto mc = startDbUpdate();
            pqxx::work txn(conn);
-            time_t now = time(nullptr);
+            time_t now = time(0);
            if (!buildOneDone && build->id == buildOne) buildOneDone = true;
            printMsg(lvlInfo, "marking build %1% as succeeded (cached)", build->id);
            markSucceededBuild(txn, build, res, true, now, now);
@ -356,7 +355,7 @@ void State::processQueueChange(Connection & conn)
        pqxx::work txn(conn);
        auto res = txn.exec("select id, globalPriority from Builds where finished = 0");
        for (auto const & row : res)
-            currentIds[row["id"].as<BuildID>()] = row["globalPriority"].as<int>();
+            currentIds[row["id"].as<BuildID>()] = row["globalPriority"].as<BuildID>();
    }

    {
@ -439,7 +438,7 @@ Step::ptr State::createStep(ref<Store> destStore,
    Build::ptr referringBuild, Step::ptr referringStep, std::set<StorePath> & finishedDrvs,
    std::set<Step::ptr> & newSteps, std::set<Step::ptr> & newRunnable)
 {
-    if (finishedDrvs.find(drvPath) != finishedDrvs.end()) return nullptr;
+    if (finishedDrvs.find(drvPath) != finishedDrvs.end()) return 0;

    /* Check if the requested step already exists. If not, create a
       new step. In any case, make the step reachable from
@ -517,7 +516,7 @@ Step::ptr State::createStep(ref<Store> destStore,
    std::map<DrvOutput, std::optional<StorePath>> paths;
    for (auto & [outputName, maybeOutputPath] : destStore->queryPartialDerivationOutputMap(drvPath, &*localStore)) {
        auto outputHash = outputHashes.at(outputName);
-        paths.insert({{.drvHash=outputHash, .outputName=outputName}, maybeOutputPath});
+        paths.insert({{outputHash, outputName}, maybeOutputPath});
    }

    auto missing = getMissingRemotePaths(destStore, paths);
@ -561,7 +560,7 @@ Step::ptr State::createStep(ref<Store> destStore,
                auto & path = *pathOpt;

                try {
-                    time_t startTime = time(nullptr);
+                    time_t startTime = time(0);

                    if (localStore->isValidPath(path))
                        printInfo("copying output ‘%1%’ of ‘%2%’ from local store",
@ -579,7 +578,7 @@ Step::ptr State::createStep(ref<Store> destStore,
                        StorePathSet { path },
                        NoRepair, CheckSigs, NoSubstitute);

-                    time_t stopTime = time(nullptr);
+                    time_t stopTime = time(0);

                    {
                        auto mc = startDbUpdate();
@ -603,7 +602,7 @@ Step::ptr State::createStep(ref<Store> destStore,
    // FIXME: check whether all outputs are in the binary cache.
    if (valid) {
        finishedDrvs.insert(drvPath);
-        return nullptr;
+        return 0;
    }

    /* No, we need to build. */
@ -611,7 +610,7 @@ Step::ptr State::createStep(ref<Store> destStore,

    /* Create steps for the dependencies. */
    for (auto & i : step->drv->inputDrvs.map) {
-        auto dep = createStep(destStore, conn, build, i.first, nullptr, step, finishedDrvs, newSteps, newRunnable);
+        auto dep = createStep(destStore, conn, build, i.first, 0, step, finishedDrvs, newSteps, newRunnable);
        if (dep) {
            auto step_(step->state.lock());
            step_->deps.insert(dep);
@ -659,11 +658,11 @@ Jobset::ptr State::createJobset(pqxx::work & txn,
    auto res2 = txn.exec_params
        ("select s.startTime, s.stopTime from BuildSteps s join Builds b on build = id "
         "where s.startTime is not null and s.stopTime > $1 and jobset_id = $2",
-         time(nullptr) - Jobset::schedulingWindow * 10,
+         time(0) - Jobset::schedulingWindow * 10,
         jobsetID);
    for (auto const & row : res2) {
-        auto startTime = row["startTime"].as<time_t>();
-        auto stopTime = row["stopTime"].as<time_t>();
+        time_t startTime = row["startTime"].as<time_t>();
+        time_t stopTime = row["stopTime"].as<time_t>();
        jobset->addStep(startTime, stopTime - startTime);
    }

@ -703,7 +702,7 @@ BuildOutput State::getBuildOutputCached(Connection & conn, nix::ref<nix::Store>
             "where finished = 1 and (buildStatus = 0 or buildStatus = 6) and path = $1",
             localStore->printStorePath(output));
        if (r.empty()) continue;
-        auto id = r[0][0].as<BuildID>();
+        BuildID id = r[0][0].as<BuildID>();

        printInfo("reusing build %d", id);

@ -728,7 +727,7 @@ BuildOutput State::getBuildOutputCached(Connection & conn, nix::ref<nix::Store>
                product.fileSize = row[2].as<off_t>();
            }
            if (!row[3].is_null())
-                product.sha256hash = Hash::parseAny(row[3].as<std::string>(), HashType::SHA256);
+                product.sha256hash = Hash::parseAny(row[3].as<std::string>(), htSHA256);
            if (!row[4].is_null())
                product.path = row[4].as<std::string>();
            product.name = row[5].as<std::string>();
--- a/src/hydra-queue-runner/state.hh
+++ b/src/hydra-queue-runner/state.hh
@ -8,7 +8,6 @@
 #include <queue>
 #include <regex>
 #include <semaphore>
-#include <utility>

 #include <prometheus/counter.h>
 #include <prometheus/gauge.h>
@ -27,16 +26,16 @@
 #include "machines.hh"


-using BuildID = unsigned int;
+typedef unsigned int BuildID;

-using JobsetID = unsigned int;
+typedef unsigned int JobsetID;

-using system_time = std::chrono::time_point<std::chrono::system_clock>;
+typedef std::chrono::time_point<std::chrono::system_clock> system_time;

-using counter = std::atomic<unsigned long>;
+typedef std::atomic<unsigned long> counter;


-enum BuildStatus {
+typedef enum {
    bsSuccess = 0,
    bsFailed = 1,
    bsDepFailed = 2, // builds only
@ -50,10 +49,10 @@ enum BuildStatus {
    bsNarSizeLimitExceeded = 11,
    bsNotDeterministic = 12,
    bsBusy = 100, // not stored
-};
+} BuildStatus;


-enum StepState {
+typedef enum {
    ssPreparing = 1,
    ssConnecting = 10,
    ssSendingInputs = 20,
@ -61,7 +60,7 @@ enum StepState {
    ssWaitingForLocalSlot = 35,
    ssReceivingOutputs = 40,
    ssPostProcessing = 50,
-};
+} StepState;


 struct RemoteResult
@ -79,7 +78,7 @@ struct RemoteResult
    unsigned int overhead = 0;
    nix::Path logFile;

-    [[nodiscard]] BuildStatus buildStatus() const
+    BuildStatus buildStatus() const
    {
        return stepStatus == bsCachedFailure ? bsFailed : stepStatus;
    }
@ -96,10 +95,10 @@ class Jobset
 {
 public:

-    using ptr = std::shared_ptr<Jobset>;
-    using wptr = std::weak_ptr<Jobset>;
+    typedef std::shared_ptr<Jobset> ptr;
+    typedef std::weak_ptr<Jobset> wptr;

-    static const time_t schedulingWindow = static_cast<time_t>(24 * 60 * 60);
+    static const time_t schedulingWindow = 24 * 60 * 60;

 private:

@ -116,7 +115,7 @@ public:
        return (double) seconds / shares;
    }

-    void setShares(unsigned int shares_)
+    void setShares(int shares_)
    {
        assert(shares_ > 0);
        shares = shares_;
@ -132,8 +131,8 @@ public:

 struct Build
 {
-    using ptr = std::shared_ptr<Build>;
-    using wptr = std::weak_ptr<Build>;
+    typedef std::shared_ptr<Build> ptr;
+    typedef std::weak_ptr<Build> wptr;

    BuildID id;
    nix::StorePath drvPath;
@ -164,8 +163,8 @@ struct Build

 struct Step
 {
-    using ptr = std::shared_ptr<Step>;
-    using wptr = std::weak_ptr<Step>;
+    typedef std::shared_ptr<Step> ptr;
+    typedef std::weak_ptr<Step> wptr;

    nix::StorePath drvPath;
    std::unique_ptr<nix::Derivation> drv;
@ -222,8 +221,13 @@ struct Step

    nix::Sync<State> state;

-    Step(nix::StorePath  drvPath) : drvPath(std::move(drvPath))
+    Step(const nix::StorePath & drvPath) : drvPath(drvPath)
    { }
+
+    ~Step()
+    {
+        //printMsg(lvlError, format("destroying step %1%") % drvPath);
+    }
 };


@ -235,7 +239,7 @@ void visitDependencies(std::function<void(Step::ptr)> visitor, Step::ptr step);

 struct Machine : nix::Machine
 {
-    using ptr = std::shared_ptr<Machine>;
+    typedef std::shared_ptr<Machine> ptr;

    /* TODO Get rid of: `nix::Machine::storeUri` is normalized in a way
       we are not yet used to, but once we are, we don't need this. */
@ -250,7 +254,7 @@ struct Machine : nix::Machine
    float speedFactorFloat = 1.0;

    struct State {
-        using ptr = std::shared_ptr<State>;
+        typedef std::shared_ptr<State> ptr;
        counter currentJobs{0};
        counter nrStepsDone{0};
        counter totalStepTime{0}; // total time for steps, including closure copying
@ -354,22 +358,22 @@ private:
    bool useSubstitutes = false;

    /* The queued builds. */
-    using Builds = std::map<BuildID, Build::ptr>;
+    typedef std::map<BuildID, Build::ptr> Builds;
    nix::Sync<Builds> builds;

    /* The jobsets. */
-    using Jobsets = std::map<std::pair<std::string, std::string>, Jobset::ptr>;
+    typedef std::map<std::pair<std::string, std::string>, Jobset::ptr> Jobsets;
    nix::Sync<Jobsets> jobsets;

    /* All active or pending build steps (i.e. dependencies of the
       queued builds). Note that these are weak pointers. Steps are
       kept alive by being reachable from Builds or by being in
       progress. */
-    using Steps = std::map<nix::StorePath, Step::wptr>;
+    typedef std::map<nix::StorePath, Step::wptr> Steps;
    nix::Sync<Steps> steps;

    /* Build steps that have no unbuilt dependencies. */
-    using Runnable = std::list<Step::wptr>;
+    typedef std::list<Step::wptr> Runnable;
    nix::Sync<Runnable> runnable;

    /* CV for waking up the dispatcher. */
@ -381,7 +385,7 @@ private:

    /* The build machines. */
    std::mutex machinesReadyLock;
-    using Machines = std::map<std::string, Machine::ptr>;
+    typedef std::map<std::string, Machine::ptr> Machines;
    nix::Sync<Machines> machines; // FIXME: use atomic_shared_ptr

    /* Throttler for CPU-bound local work. */
@ -397,7 +401,6 @@ private:
    counter nrStepsDone{0};
    counter nrStepsBuilding{0};
    counter nrStepsCopyingTo{0};
-    counter nrStepsWaitingForDownloadSlot{0};
    counter nrStepsCopyingFrom{0};
    counter nrStepsWaiting{0};
    counter nrUnsupportedSteps{0};
@ -428,7 +431,7 @@ private:

    struct MachineReservation
    {
-        using ptr = std::shared_ptr<MachineReservation>;
+        typedef std::shared_ptr<MachineReservation> ptr;
        State & state;
        Step::ptr step;
        Machine::ptr machine;
@ -531,7 +534,7 @@ private:
    void finishBuildStep(pqxx::work & txn, const RemoteResult & result, BuildID buildId, unsigned int stepNr,
        const std::string & machine);

-    unsigned int createSubstitutionStep(pqxx::work & txn, time_t startTime, time_t stopTime,
+    int createSubstitutionStep(pqxx::work & txn, time_t startTime, time_t stopTime,
        Build::ptr build, const nix::StorePath & drvPath, const nix::Derivation drv, const std::string & outputName, const nix::StorePath & storePath);

    void updateBuild(pqxx::work & txn, Build::ptr build, BuildStatus status);
@ -591,7 +594,6 @@ private:
    enum StepResult { sDone, sRetry, sMaybeCancelled };
    StepResult doBuildStep(nix::ref<nix::Store> destStore,
        MachineReservation::ptr & reservation,
-        Connection & conn,
        std::shared_ptr<ActiveStep> activeStep);

    void buildRemote(nix::ref<nix::Store> destStore,
@ -620,6 +622,8 @@ private:

    void addRoot(const nix::StorePath & storePath);

+    void runMetricsExporter();
+
 public:

    void showStatus();
--- a/src/lib/Hydra/Controller/API.pm
+++ b/src/lib/Hydra/Controller/API.pm
@ -242,35 +242,23 @@ sub push : Chained('api') PathPart('push') Args(0) {
    $c->{stash}->{json}->{jobsetsTriggered} = [];

    my $force = exists $c->request->query_params->{force};
-    my @jobsetNames = split /,/, ($c->request->query_params->{jobsets} // "");
-    my @jobsets;
-
-    foreach my $s (@jobsetNames) {
+    my @jobsets = split /,/, ($c->request->query_params->{jobsets} // "");
+    foreach my $s (@jobsets) {
        my ($p, $j) = parseJobsetName($s);
        my $jobset = $c->model('DB::Jobsets')->find($p, $j);
-        push @jobsets, $jobset if defined $jobset;
+        next unless defined $jobset && ($force || ($jobset->project->enabled && $jobset->enabled));
+        triggerJobset($self, $c, $jobset, $force);
    }

    my @repos = split /,/, ($c->request->query_params->{repos} // "");
    foreach my $r (@repos) {
-        foreach ($c->model('DB::Jobsets')->search(
+        triggerJobset($self, $c, $_, $force) foreach $c->model('DB::Jobsets')->search(
            { 'project.enabled' => 1, 'me.enabled' => 1 },
            {
                join => 'project',
                where => \ [ 'exists (select 1 from JobsetInputAlts where project = me.project and jobset = me.name and value = ?)', [ 'value', $r ] ],
                order_by => 'me.id DESC'
-            })) {
-            push @jobsets, $_;
-        }
-    }
-
-    foreach my $jobset (@jobsets) {
-        requireRestartPrivileges($c, $jobset->project);
-    }
-
-    foreach my $jobset (@jobsets) {
-        next unless defined $jobset && ($force || ($jobset->project->enabled && $jobset->enabled));
-        triggerJobset($self, $c, $jobset, $force);
+            });
    }

    $self->status_ok(
@ -285,7 +273,7 @@ sub push_github : Chained('api') PathPart('push-github') Args(0) {
    $c->{stash}->{json}->{jobsetsTriggered} = [];

    my $in = $c->request->{data};
-    my $owner = $in->{repository}->{owner}->{login} or die;
+    my $owner = $in->{repository}->{owner}->{name} or die;
    my $repo = $in->{repository}->{name} or die;
    print STDERR "got push from GitHub repository $owner/$repo\n";

@ -297,23 +285,6 @@ sub push_github : Chained('api') PathPart('push-github') Args(0) {
    $c->response->body("");
 }

-sub push_gitea : Chained('api') PathPart('push-gitea') Args(0) {
-    my ($self, $c) = @_;
-
-    $c->{stash}->{json}->{jobsetsTriggered} = [];
-
-    my $in = $c->request->{data};
-    my $url = $in->{repository}->{clone_url} or die;
-    $url =~ s/.git$//;
-    print STDERR "got push from Gitea repository $url\n";
-
-    triggerJobset($self, $c, $_, 0) foreach $c->model('DB::Jobsets')->search(
-        { 'project.enabled' => 1, 'me.enabled' => 1 },
-        { join => 'project'
-        , where => \ [ 'me.flake like ? or exists (select 1 from JobsetInputAlts where project = me.project and jobset = me.name and value like ?)', [ 'flake', "%$url%"], [ 'value', "%$url%" ] ]
-        });
-    $c->response->body("");
-}


 1;
--- a/src/lib/Hydra/Controller/Root.pm
+++ b/src/lib/Hydra/Controller/Root.pm
@ -35,7 +35,6 @@ sub noLoginNeeded {

  return $whitelisted ||
         $c->request->path eq "api/push-github" ||
-         $c->request->path eq "api/push-gitea" ||
         $c->request->path eq "google-login" ||
         $c->request->path eq "github-redirect" ||
         $c->request->path eq "github-login" ||
@ -81,7 +80,7 @@ sub begin :Private {
    $_->supportedInputTypes($c->stash->{inputTypes}) foreach @{$c->hydra_plugins};

    # XSRF protection: require POST requests to have the same origin.
-    if ($c->req->method eq "POST" && $c->req->path ne "api/push-github" && $c->req->path ne "api/push-gitea") {
+    if ($c->req->method eq "POST" && $c->req->path ne "api/push-github") {
        my $referer = $c->req->header('Referer');
        $referer //= $c->req->header('Origin');
        my $base = $c->req->base;
--- a/src/lib/Hydra/Helper/Nix.pm
+++ b/src/lib/Hydra/Helper/Nix.pm
@ -412,7 +412,8 @@ sub readIntoSocket{
    my $sock;

    eval {
-        open($sock, "-|", @{$args{cmd}}) or die q(failed to open socket from command:\n $x);
+        my $x= join(" ", @{$args{cmd}});
+        open($sock, "-|", $x) or die q(failed to open socket from command:\n $x);
    };

    return $sock;
--- a/src/sql/hydra.sql
+++ b/src/sql/hydra.sql
@ -6,7 +6,7 @@
 --    add a map of the lowercase name of your table to the CamelCase
 --    version of your table.
 --
-- 3. Run `just update-dbix` in the root
+-- 3. Run `make -C src/sql update-dbix` in the root
 --    of the project directory, and git add / git commit the changed,
 --    generated files.
 --
--- a/t/Hydra/Controller/API/checks.t
+++ b/t/Hydra/Controller/API/checks.t
@ -35,17 +35,6 @@ my $queuedBuilds = $ctx->makeAndEvaluateJobset(
    build => 0
 );

-# Login and save cookie for future requests
-my $req = request(POST '/login',
-    Referer => 'http://localhost/',
-    Content => {
-        username => 'root',
-        password => 'rootPassword'
-    }
-);
-is($req->code, 302, "Logging in gets a 302");
-my $cookie = $req->header("set-cookie");
-
 subtest "/api/queue" => sub {
    my $response = request(GET '/api/queue?nr=1');
    ok($response->is_success, "The API enpdoint showing the queue returns 200.");
@ -113,17 +102,6 @@ subtest "/api/nrbuilds" => sub {
 };

 subtest "/api/push" => sub {
-    subtest "without authentication" => sub {
-        my $build = $finishedBuilds->{"one_job"};
-        my $jobset = $build->jobset;
-        my $projectName = $jobset->project->name;
-        my $jobsetName = $jobset->name;
-        is($jobset->forceeval, undef, "The existing jobset is not set to be forced to eval");
-
-        my $response = request(GET "/api/push?jobsets=$projectName:$jobsetName&force=1");
-        is($response->code, 403, "The API enpdoint for triggering jobsets requires authentication.");
-    };
-
    subtest "with a specific jobset" => sub {
        my $build = $finishedBuilds->{"one_job"};
        my $jobset = $build->jobset;
@ -131,8 +109,7 @@ subtest "/api/push" => sub {
        my $jobsetName = $jobset->name;
        is($jobset->forceeval, undef, "The existing jobset is not set to be forced to eval");

-        my $response = request(GET "/api/push?jobsets=$projectName:$jobsetName&force=1",
-                               Cookie => $cookie);
+        my $response = request(GET "/api/push?jobsets=$projectName:$jobsetName&force=1");
        ok($response->is_success, "The API enpdoint for triggering jobsets returns 200.");

        my $data = is_json($response);
@ -151,8 +128,7 @@ subtest "/api/push" => sub {

        print STDERR $repo;

-        my $response = request(GET "/api/push?repos=$repo&force=1",
-                               Cookie => $cookie);
+        my $response = request(GET "/api/push?repos=$repo&force=1");
        ok($response->is_success, "The API enpdoint for triggering jobsets returns 200.");

        my $data = is_json($response);
@ -196,7 +172,7 @@ subtest "/api/push-github" => sub {
            "Content" => encode_json({
                repository => {
                    owner => {
-                        login => "OWNER",
+                        name => "OWNER",
                    },
                    name => "LEGACY-REPO",
                }
@ -222,7 +198,7 @@ subtest "/api/push-github" => sub {
            "Content" => encode_json({
                repository => {
                    owner => {
-                        login => "OWNER",
+                        name => "OWNER",
                    },
                    name => "FLAKE-REPO",
                }
--- a/t/Hydra/Controller/Project/delete.t
+++ b/t/Hydra/Controller/Project/delete.t
@ -11,14 +11,20 @@ my $ctx = test_context();

 Catalyst::Test->import('Hydra');

-$ctx->db();  # Ensure DB initialization.
+my $user = $ctx->db()->resultset('Users')->create({
+    username => 'alice',
+    emailaddress => 'root@invalid.org',
+    password => '!'
+});
+$user->setPassword('foobar');
+$user->userroles->update_or_create({ role => 'admin' });

 # Login and save cookie for future requests
 my $req = request(POST '/login',
    Referer => 'http://localhost/',
    Content => {
-        username => 'root',
-        password => 'rootPassword'
+        username => 'alice',
+        password => 'foobar'
    }
 );
 is($req->code, 302, "Logging in gets a 302");
--- a/t/lib/HydraTestContext.pm
+++ b/t/lib/HydraTestContext.pm
@ -101,7 +101,7 @@ sub new {
        $opts{'before_init'}->($self);
    }

-    expectOkay(30, ("hydra-init"));
+    expectOkay(5, ("hydra-init"));

    return $self;
 }
@ -115,13 +115,11 @@ sub db {
        $self->{_db} = Hydra::Model::DB->new();

        if (!(defined $setup && $setup == 0)) {
-            my $user = $self->{_db}->resultset('Users')->create({
+            $self->{_db}->resultset('Users')->create({
                username => "root",
                emailaddress => 'root@invalid.org',
-                password => '!'
+                password => ''
            });
-            $user->setPassword('rootPassword');
-            $user->userroles->update_or_create({ role => 'admin' });
        }
    }

--- a/t/lib/LDAPContext.pm
+++ b/t/lib/LDAPContext.pm
@ -70,7 +70,7 @@ sub add_user {
    my $email = $opts{'email'} // "$name\@example";
    my $password = $opts{'password'} // rand_chars();

-    my ($res, $stdout, $stderr) = captureStdoutStderr(5, ("slappasswd", "-s", $password));
+    my ($res, $stdout, $stderr) = captureStdoutStderr(1, ("slappasswd", "-s", $password));
    if ($res) {
        die "Failed to execute slappasswd ($res): $stderr, $stdout";
    }
@ -178,7 +178,7 @@ sub start {
 sub validateConfig {
    my ($self) = @_;

-    expectOkay(5, ("slaptest", "-u", "-F", $self->{"_slapd_dir"}));
+    expectOkay(1, ("slaptest", "-u", "-F", $self->{"_slapd_dir"}));
 }

 sub _spawn {
@ -218,7 +218,7 @@ sub load_ldif {

    my $path = "${\$self->{'_tmpdir'}}/load.ldif";
    write_file($path, $content);
-    expectOkay(5, ("slapadd", "-F", $self->{"_slapd_dir"}, "-b", $suffix, "-l", $path));
+    expectOkay(1, ("slapadd", "-F", $self->{"_slapd_dir"}, "-b", $suffix, "-l", $path));
    $self->validateConfig();
 }

--- a/t/queue-runner/build-locally-with-substitutable-path.t
+++ b/t/queue-runner/build-locally-with-substitutable-path.t
@ -39,7 +39,7 @@ subtest "Building, caching, and then garbage collecting the underlying job" => s

    ok(unlink(Hydra::Helper::Nix::gcRootFor($path)), "Unlinking the GC root for underlying Dependency succeeds");

-    (my $ret, my $stdout, my $stderr) = captureStdoutStderr(15, "nix-store", "--delete", $path);
+    (my $ret, my $stdout, my $stderr) = captureStdoutStderr(5, "nix-store", "--delete", $path);
    is($ret, 0, "Deleting the underlying dependency should succeed");
 };

--- a/t/scripts/hydra-create-user.t
+++ b/t/scripts/hydra-create-user.t
@ -9,7 +9,7 @@ my $db = $ctx->db();

 subtest "Handling password and password hash creation" => sub {
    subtest "Creating a user with a plain text password (insecure) stores the password securely" => sub {
-        my ($res, $stdout, $stderr) = captureStdoutStderr(15, ("hydra-create-user", "plain-text-user", "--password", "foobar"));
+        my ($res, $stdout, $stderr) = captureStdoutStderr(5, ("hydra-create-user", "plain-text-user", "--password", "foobar"));
        is($res, 0, "hydra-create-user should exit zero");
        like($stderr, qr/Submitting plaintext passwords as arguments is deprecated and will be removed/, "Submitting a plain text password is deprecated.");

@ -23,7 +23,7 @@ subtest "Handling password and password hash creation" => sub {
    };

    subtest "Creating a user with a sha1 password (still insecure) stores the password as a hashed sha1" => sub {
-        my ($res, $stdout, $stderr) = captureStdoutStderr(15, ("hydra-create-user", "old-password-hash-user", "--password-hash", "8843d7f92416211de9ebb963ff4ce28125932878"));
+        my ($res, $stdout, $stderr) = captureStdoutStderr(5, ("hydra-create-user", "old-password-hash-user", "--password-hash", "8843d7f92416211de9ebb963ff4ce28125932878"));
        is($res, 0, "hydra-create-user should exit zero");

        my $user = $db->resultset('Users')->find({ username => "old-password-hash-user" });
@ -36,7 +36,7 @@ subtest "Handling password and password hash creation" => sub {
    };

    subtest "Creating a user with an argon2 password stores the password as given" => sub {
-        my ($res, $stdout, $stderr) = captureStdoutStderr(15, ("hydra-create-user", "argon2-hash-user", "--password-hash", '$argon2id$v=19$m=262144,t=3,p=1$tMnV5paYjmIrUIb6hylaNA$M8/e0i3NGrjhOliVLa5LqQ'));
+        my ($res, $stdout, $stderr) = captureStdoutStderr(5, ("hydra-create-user", "argon2-hash-user", "--password-hash", '$argon2id$v=19$m=262144,t=3,p=1$tMnV5paYjmIrUIb6hylaNA$M8/e0i3NGrjhOliVLa5LqQ'));
        is($res, 0, "hydra-create-user should exit zero");

        my $user = $db->resultset('Users')->find({ username => "argon2-hash-user" });
@ -50,7 +50,7 @@ subtest "Handling password and password hash creation" => sub {

    subtest "Creating a user by prompting for the password" => sub {
        subtest "with the same password twice" => sub {
-            my ($res, $stdout, $stderr) = captureStdoutStderrWithStdin(15, ["hydra-create-user", "prompted-pass-user", "--password-prompt"], "my-password\nmy-password\n");
+            my ($res, $stdout, $stderr) = captureStdoutStderrWithStdin(5, ["hydra-create-user", "prompted-pass-user", "--password-prompt"], "my-password\nmy-password\n");
            is($res, 0, "hydra-create-user should exit zero");

            my $user = $db->resultset('Users')->find({ username => "prompted-pass-user" });
@ -62,7 +62,7 @@ subtest "Handling password and password hash creation" => sub {
        };

        subtest "With mismatched password confirmation" => sub {
-            my ($res, $stdout, $stderr) = captureStdoutStderrWithStdin(15, ["hydra-create-user", "prompted-pass-user", "--password-prompt"], "my-password\nnot-my-password\n");
+            my ($res, $stdout, $stderr) = captureStdoutStderrWithStdin(5, ["hydra-create-user", "prompted-pass-user", "--password-prompt"], "my-password\nnot-my-password\n");
            isnt($res, 0, "hydra-create-user should exit non-zero");
        };
    };
@ -76,7 +76,7 @@ subtest "Handling password and password hash creation" => sub {
        );

        for my $case (@cases) {
-            my ($res, $stdout, $stderr) = captureStdoutStderr(15, (
+            my ($res, $stdout, $stderr) = captureStdoutStderr(5, (
                "hydra-create-user", "bogus-password-options", @{$case}));
            like($stderr, qr/please specify only one of --password-prompt or --password-hash/, "We get an error about specifying the password");
            isnt($res, 0, "hydra-create-user should exit non-zero with conflicting " . join(" ", @{$case}));
@ -84,7 +84,7 @@ subtest "Handling password and password hash creation" => sub {
    };

    subtest "A password is not required for creating a Google-based account" => sub {
-        my ($res, $stdout, $stderr) = captureStdoutStderr(15, (
+        my ($res, $stdout, $stderr) = captureStdoutStderr(5, (
            "hydra-create-user", "google-account", "--type", "google"));
        is($res, 0, "hydra-create-user should exit zero");
    };
--- a/t/scripts/hydra-init.t
+++ b/t/scripts/hydra-init.t
@ -28,7 +28,7 @@ subtest "hydra-init upgrades user's password hashes from sha1 to sha1 inside Arg
    $janet->setPassword("foobar");

    is($alice->password, "8843d7f92416211de9ebb963ff4ce28125932878", "Alices's sha1 is stored in the database");
-    my ($res, $stdout, $stderr) = captureStdoutStderr(30, ("hydra-init"));
+    my ($res, $stdout, $stderr) = captureStdoutStderr(5, ("hydra-init"));
    if ($res != 0) {
        is($stdout, "");
        is($stderr, "");
@ -55,7 +55,7 @@ subtest "hydra-init upgrades user's password hashes from sha1 to sha1 inside Arg
    };

    subtest "Running hydra-init don't break Alice or Janet's passwords" => sub {
-        my ($res, $stdout, $stderr) = captureStdoutStderr(30, ("hydra-init"));
+        my ($res, $stdout, $stderr) = captureStdoutStderr(5, ("hydra-init"));
        is($res, 0, "hydra-init should exit zero");

        my $updatedAlice = $db->resultset('Users')->find({ username => "alice" });
--- a/t/test.pl
+++ b/t/test.pl
@ -21,7 +21,7 @@ if (defined($ENV{"NIX_BUILD_CORES"})
    print STDERR "test.pl: Defaulting \$YATH_JOB_COUNT to \$NIX_BUILD_CORES (${\$ENV{'NIX_BUILD_CORES'}})\n";
 }

-system($^X, find_yath(), '-D', 'test', '--qvf', '--event-timeout', 240, '--default-search' => './', @ARGV);
+system($^X, find_yath(), '-D', 'test', '--default-search' => './', @ARGV);
 my $exit = $?;

 # This makes sure it works with prove.