Commit graph

11 commits

Author SHA1 Message Date
Eelco Dolstra 462421d345 Backport libfetchers from the flakes branch
This provides a pluggable mechanism for defining new fetchers. It adds
a builtin function 'fetchTree' that generalizes existing fetchers like
'fetchGit', 'fetchMercurial' and 'fetchTarball'. 'fetchTree' takes a
set of attributes, e.g.

  fetchTree {
    type = "git";
    url = "https://example.org/repo.git";
    ref = "some-branch";
    rev = "abcdef...";
  }

The existing fetchers are just wrappers around this. Note that the
input attributes to fetchTree are the same as flake input
specifications and flake lock file entries.

All fetchers share a common cache stored in
~/.cache/nix/fetcher-cache-v1.sqlite. This replaces the ad hoc caching
mechanisms in fetchGit and download.cc (e.g. ~/.cache/nix/{tarballs,git-revs*}).

This also adds support for Git worktrees (c169ea5904).
2020-04-07 09:03:14 +02:00
Eelco Dolstra 0a10854f85 Misc changes from the flakes branch 2020-03-24 14:34:47 +01:00
Graham Christensen 02098d2073 fetchGit: use a better caching scheme
The current usage technically works by putting multiple different
repos in to the same git directory. However, it is very slow as
Git tries very hard to find common commits between the two
repositories. If the two repositories are large (like Nixpkgs and
another long-running project,) it is maddeningly slow.

This change busts the cache for existing deployments, but users
will be promptly repaid in per-repository performance.
2018-08-17 11:27:34 -04:00
Eelco Dolstra d4dcffd643
Add pure evaluation mode
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.
2018-01-16 19:23:18 +01:00
Will Dietz 84d9e213d2 fetchGit.sh: Test we don't "corrupt" cache if invoke w/o git avail 2018-01-09 08:58:19 -06:00
Will Dietz 2e6f06c37e fetchGit: Fix handling of local repo when not using 'master' branch
Add tests checking this behavior.
2017-12-22 15:29:52 -06:00
Shea Levy eedbc4e06c
fetchGit: Ignore tarballTtl if rev is set and not in the repo.
Fixes .
2017-11-24 06:09:24 -05:00
Eelco Dolstra d7da6c9ea9
fetchGit/fetchMercurial: Fix directory inclusion check
E.g. the existence of .gitignore would cause .git to be included.
2017-11-21 19:34:46 +01:00
Eelco Dolstra fd10f6f241
Show when tests are skipped
Also, don't depend on tput (ncurses). It's really not needed since
ANSI escape sequences have been standardized for 35 years or so.
2017-11-07 12:09:57 +01:00
Eelco Dolstra ee6ac38848
fetchGit/fetchMercurial: Filter out directories with untracked files 2017-11-03 13:55:31 +01:00
Eelco Dolstra 4dee01da7c
fetchGit: Add a test 2017-11-03 13:55:30 +01:00