nix-store --export, nix-store --dump, and nix dump-path would previously
fail silently if writing the data out failed, because
a) FdSink::write ignored exceptions, and
b) the commands relied on FdSink's destructor, which ignores
exceptions, to flush the data out.
This could cause rather opaque issues with installing nixos, because
nix-store --export would happily proceed even if it couldn't write its
data out (e.g. if nix-store --import on the other side of the pipe
failed).
This commit adds tests that expose these issues in the nix-store
commands, and fixes them for all three.
All ANSI sequences except color setting are now filtered out. In
particular, terminal resets (such as from NixOS VM tests) are filtered
out.
Also, fix the completely broken tab character handling.
the case of hydra where the overhead of single threaded encoding is more
noticeable e.g most of the time spent in "Sending inputs"/"Receiving outputs"
is due to compression while the actual upload to the binary cache seems
to be negligible.
In this mode, the following restrictions apply:
* The builtins currentTime, currentSystem and storePath throw an
error.
* $NIX_PATH and -I are ignored.
* fetchGit and fetchMercurial require a revision hash.
* fetchurl and fetchTarball require a sha256 attribute.
* No file system access is allowed outside of the paths returned by
fetch{Git,Mercurial,url,Tarball}. Thus 'nix build -f ./foo.nix' is
not allowed.
Thus, the evaluation result is completely reproducible from the
command line arguments. E.g.
nix build --pure-eval '(
let
nix = fetchGit { url = https://github.com/NixOS/nixpkgs.git; rev = "9c927de4b179a6dd210dd88d34bda8af4b575680"; };
nixpkgs = fetchGit { url = https://github.com/NixOS/nixpkgs.git; ref = "release-17.09"; rev = "66b4de79e3841530e6d9c6baf98702aa1f7124e4"; };
in (import (nix + "/release.nix") { inherit nix nixpkgs; }).build.x86_64-linux
)'
The goal is to enable completely reproducible and traceable
evaluation. For example, a NixOS configuration could be fully
described by a single Git commit hash. 'nixos-rebuild' would do
something like
nix build --pure-eval '(
(import (fetchGit { url = file:///my-nixos-config; rev = "..."; })).system
')
where the Git repository /my-nixos-config would use further fetchGit
calls or Git externals to fetch Nixpkgs and whatever other
dependencies it has. Either way, the commit hash would uniquely
identify the NixOS configuration and allow it to reproduced.
* Look for both 'brotli' and 'bro' as external command,
since upstream has renamed it in newer versions.
If neither are found, current runtime behavior
is preserved: try to find 'bro' on PATH.
* Limit amount handed to BrotliEncoderCompressStream
to ensure interrupts are processed in a timely manner.
Testing shows negligible performance impact.
(Other compression sinks don't seem to require this)
For example, you can write
src = fetchgit ./.;
and if ./. refers to an unclean working tree, that tree will be copied
to the Nix store. This removes the need for "cleanSource".
Used to determine symlink size with stat and value with readlink.
This could technically result in garbage if symlink changed between
calls. Also gets around the broken stat implementation in our
network filesystem (returns size + 1 giving a byte of garbage).
The worker threads could exit prematurely if they finished processing
all items while the main thread was still adding items. In particular,
this caused hanging nix-store --serve processes in the build farm.
Also, process items from the main thread.
This is a hack to make hydra-queue-runner free its temproots
periodically, thereby ensuring that garbage collection of the
corresponding paths is not blocked until the queue runner is
restarted.
It would be better if temproots could be released earlier than at
process exit. I started working on a RAII object returned by functions
like addToStore() that releases temproots. However, this would be a
pretty massive change so I gave up on it for now.
In particular, process() won't return as long as there are active
items. This prevents work item lambdas from referring to stack frames
that no longer exist.
E.g.
nix run nixpkgs.hello -c hello --greeting Hallo
Note that unlike "nix-shell --command", no quoting of arguments is
necessary.
"-c" (short for "--command") cannot be combined with "--" because they
both consume all remaining arguments. But since installables shouldn't
start with a dash, this is unlikely to cause problems.
Besides being unused, this function has a bug that it will incorrectly
decode the path component Ubuntu\04016.04.2\040LTS\040amd64 as
"Ubuntu.04.2 LTS amd64" instead of "Ubuntu 16.04.2 LTS amd64".
The package list is now cached in
~/.cache/nix/package-search.json. This gives a substantial speedup to
"nix search" queries. For example (on an SSD):
First run: (no package search cache, cold page cache)
$ time nix search blender
Attribute name: nixpkgs.blender
Package name: blender
Version: 2.78c
Description: 3D Creation/Animation/Publishing System
real 0m6.516s
Second run: (package search cache populated)
$ time nix search blender
Attribute name: nixpkgs.blender
Package name: blender
Version: 2.78c
Description: 3D Creation/Animation/Publishing System
real 0m0.143s
Thus, instead of ‘--option <name> <value>’, you can write ‘--<name>
<value>’. So
--option http-connections 100
becomes
--http-connections 100
Apart from brevity, the difference is that it's not an error to set a
non-existent option via --option, but unrecognized arguments are
fatal.
Boolean options have special treatment: they're mapped to the
argument-less flags ‘--<name>’ and ‘--no-<name>’. E.g.
--option auto-optimise-store false
becomes
--no-auto-optimise-store
This caused "nix-store --import" to compute an incorrect hash on NARs
that don't fit in an unsigned int. The import would succeed, but
"nix-store --verify-path" or subsequent exports would detect an
incorrect hash.
A deeper issue is that the export/import format does not contain a
hash, so we can't detect such issues early.
Also, I learned that -Wall does not warn about this.
The typical use is to inherit Config and add Setting<T> members:
class MyClass : private Config
{
Setting<int> foo{this, 123, "foo", "the number of foos to use"};
Setting<std::string> bar{this, "blabla", "bar", "the name of the bar"};
MyClass() : Config(readConfigFile("/etc/my-app.conf"))
{
std::cout << foo << "\n"; // will print 123 unless overriden
}
};
Currently, this is used by Store and its subclasses for store
parameters. You now get a warning if you specify a non-existant store
parameter in a store URI.
This is useless because the client also caches path info, and can
cause problems for long-running clients like hydra-queue-runner
(i.e. it may return cached info about paths that have been
garbage-collected).
You can now set the store parameter "text-compression=br" to compress
textual files in the binary cache (i.e. narinfo and logs) using
Brotli. This sets the Content-Encoding header; the extension of
compressed files is unchanged.
You can separately specify the compression of log files using
"log-compression=br". This is useful when you don't want to compress
narinfo files for backward compatibility.
Build logs on cache.nixos.org are compressed using Brotli (since this
allows them to be decompressed automatically by Chrome and Firefox),
so it's handy if "nix log" can decompress them.
* Unify SSH code in SSHStore and LegacySSHStore.
* Fix a race starting the SSH master. We now wait synchronously for
the SSH master to finish starting. This prevents the SSH clients
from starting their own connections.
* Don't use a master if max-connections == 1.
* Add a "max-connections" store parameter.
* Add a "compress" store parameter.
This allows <nix/fetchurl.nix> to fetch private Git/Mercurial
repositories, e.g.
import <nix/fetchurl.nix> {
url = https://edolstra@bitbucket.org/edolstra/my-private-repo/get/80a14018daed.tar.bz2;
sha256 = "1mgqzn7biqkq3hf2697b0jc4wabkqhmzq2srdymjfa6sb9zb6qs7";
}
where /etc/nix/netrc contains:
machine bitbucket.org
login edolstra
password blabla...
This works even when sandboxing is enabled.
To do: add unpacking support (i.e. fetchzip functionality).
This adds support for s3:// URIs in all places where Nix allows URIs,
e.g. in builtins.fetchurl, builtins.fetchTarball, <nix/fetchurl.nix>
and NIX_PATH. It allows fetching resources from private S3 buckets,
using credentials obtained from the standard places (i.e. AWS_*
environment variables, ~/.aws/credentials and the EC2 metadata
server). This may not be super-useful in general, but since we already
depend on aws-sdk-cpp, it's a cheap feature to add.
Because config.h can #define things like _FILE_OFFSET_BITS=64 and not
every compilation unit includes config.h, we currently compile half of
Nix with _FILE_OFFSET_BITS=64 and other half with _FILE_OFFSET_BITS
unset. This causes major havoc with the Settings class on e.g. 32-bit ARM,
where different compilation units disagree with the struct layout.
E.g.:
diff --git a/src/libstore/globals.cc b/src/libstore/globals.cc
@@ -166,6 +166,8 @@ void Settings::update()
_get(useSubstitutes, "build-use-substitutes");
+ fprintf(stderr, "at Settings::update(): &useSubstitutes = %p\n", &nix::settings.useSubstitutes);
_get(buildUsersGroup, "build-users-group");
diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc
+++ b/src/libstore/remote-store.cc
@@ -138,6 +138,8 @@ void RemoteStore::initConnection(Connection & conn)
void RemoteStore::setOptions(Connection & conn)
{
+ fprintf(stderr, "at RemoteStore::setOptions(): &useSubstitutes = %p\n", &nix::settings.useSubstitutes);
conn.to << wopSetOptions
Gave me:
at Settings::update(): &useSubstitutes = 0xb6e5c5cb
at RemoteStore::setOptions(): &useSubstitutes = 0xb6e5c5c7
That was not a fun one to debug!
This closes a long-time bug that allowed builds to hang Nix
indefinitely (regardless of timeouts) simply by doing
exec > /dev/null 2>&1; while true; do true; done
Now, on EOF, we just send SIGKILL to the child to make sure it's
really gone.
This allows other threads to install callbacks that run in a regular,
non-signal context. In particular, we can use this to signal the
downloader thread to quit.
Closes#1183.
It failed with
AWS error uploading ‘6gaxphsyhg66mz0a00qghf9nqf7majs2.ls.xz’: Unable to parse ExceptionName: MissingContentLength Message: You must provide the Content-Length HTTP header.
possibly because the istringstream_nocopy introduced in
0d2ebb4373 doesn't supply the seek
method that the AWS library expects. So bring back the old version,
but only for S3BinaryCacheStore.
We can now write
throw Error("file '%s' not found", path);
instead of
throw Error(format("file '%s' not found") % path);
and similarly
printError("file '%s' not found", path);
instead of
printMsg(lvlError, format("file '%s' not found") % path);
We were passing "p=$PATH" rather than "p=$PATH;", resulting in some
invalid shell code.
Also, construct a separate environment for the child rather than
overwriting the parent's.
The fact that queryPathInfo() is synchronous meant that we needed a
thread for every concurrent binary cache lookup, even though they end
up being handled by the same download thread. Requiring hundreds of
threads is not a good idea. So now there is an asynchronous version of
queryPathInfo() that takes a callback function to process the
result. Similarly, enqueueDownload() now takes a callback rather than
returning a future.
Thus, a command like
nix path-info --store https://cache.nixos.org/ -r /nix/store/slljrzwmpygy1daay14kjszsr9xix063-nixos-16.09beta231.dccf8c5
that returns 4941 paths now takes 1.87s using only 2 threads (the main
thread and the downloader thread). (This is with a prewarmed
CloudFront.)
This fixes instantiation of pythonPackages.pytest that produces a
directory with less permissions during one of it's tests that leads to
a nix error like:
error: opening directory ‘/tmp/nix-build-python2.7-pytest-2.9.2.drv-0/pytest-of-user/pytest-0/testdir/test_cache_failure_warns0/.cache’: Permission denied
E.g.
$ nix-build -I nixpkgs=git://github.com/NixOS/nixpkgs '<nixpkgs>' -A hello
This is not extremely useful yet because you can't specify a
branch/revision.
Caching path info is generally useful. For instance, it speeds up "nix
path-info -rS /run/current-system" (i.e. showing the closure sizes of
all paths in the closure of the current system) from 5.6s to 0.15s.
This also eliminates some APIs like Store::queryDeriver() and
Store::queryReferences().
The flag remembering whether an Interrupted exception was thrown is
now thread-local. Thus, all threads will (eventually) throw
Interrupted. Previously, one thread would throw Interrupted, and then
the other threads wouldn't see that they were supposed to quit.
Unlike "nix-store --verify-path", this command verifies signatures in
addition to store path contents, is multi-threaded (especially useful
when verifying binary caches), and has a progress indicator.
Example use:
$ nix verify-paths --store https://cache.nixos.org -r $(type -p thunderbird)
...
[17/132 checked] checking ‘/nix/store/rawakphadqrqxr6zri2rmnxh03gqkrl3-autogen-5.18.6’
This allows a RemoteStore object to be used safely from multiple
threads concurrently. It will make multiple daemon connections if
necessary.
Note: pool.hh and sync.hh have been copied from the Hydra source tree.
Also, move a few free-standing functions into StoreAPI and Derivation.
Also, introduce a non-nullable smart pointer, ref<T>, which is just a
wrapper around std::shared_ptr ensuring that the pointer is never
null. (For reference-counted values, this is better than passing a
"T&", because the latter doesn't maintain the refcount. Usually, the
caller will have a shared_ptr keeping the value alive, but that's not
always the case, e.g., when passing a reference to a std::thread via
std::bind.)
edolstra:
“…since callers of readDirectory have to handle the possibility of
DT_UNKNOWN anyway, and we don't want to do a stat call for every
directory entry unless it's really needed.”
Previously, to build a derivation remotely, we had to copy the entire
closure of the .drv file to the remote machine, even though we only
need the top-level derivation. This is very wasteful: the closure can
contain thousands of store paths, and in some Hydra use cases, include
source paths that are very large (e.g. Git/Mercurial checkouts).
So now there is a new operation, StoreAPI::buildDerivation(), that
performs a build from an in-memory representation of a derivation
(BasicDerivation) rather than from a on-disk .drv file. The only files
that need to be in the Nix store are the sources of the derivation
(drv.inputSrcs), and the needed output paths of the dependencies (as
described by drv.inputDrvs). "nix-store --serve" exposes this
interface.
Note that this is a privileged operation, because you can construct a
derivation that builds any store path whatsoever. Fixing this will
require changing the hashing scheme (i.e., the output paths should be
computed from the other fields in BasicDerivation, allowing them to be
verified without access to other derivations). However, this would be
quite nice because it would allow .drv-free building (e.g. "nix-env
-i" wouldn't have to write any .drv files to disk).
Fixes#173.
Linus Heckemann
Jörg Thalheim