diff options
Diffstat (limited to 'tools/nixery/build-image/default.nix')
| -rw-r--r-- | tools/nixery/build-image/default.nix | 96 |
1 files changed, 15 insertions, 81 deletions
diff --git a/tools/nixery/build-image/default.nix b/tools/nixery/build-image/default.nix index 3bb5d62fb0..a61ac06bdd 100644 --- a/tools/nixery/build-image/default.nix +++ b/tools/nixery/build-image/default.nix @@ -12,84 +12,18 @@ # See the License for the specific language governing permissions and # limitations under the License. -# This file builds the tool used to calculate layer distribution and -# moves the files needed to call the Nix builds at runtime in the -# correct locations. - -{ pkgs ? null, self ? ./. - - # Because of the insanity occuring below, this function must mirror - # all arguments of build-image.nix. -, srcType ? "nixpkgs" -, srcArgs ? "nixos-19.03" -, tag ? null, name ? null, packages ? null, maxLayers ? null, popularityUrl ? null -}@args: - -let pkgs = import ./load-pkgs.nix { inherit srcType srcArgs; }; -in with pkgs; rec { - - groupLayers = buildGoPackage { - name = "group-layers"; - goDeps = ./go-deps.nix; - goPackagePath = "github.com/google/nixery/group-layers"; - - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - # WARNING: HERE BE DRAGONS! # - # # - # The hack below is used to break evaluation purity. The issue is # - # that Nixery's build instructions (the default.nix in the folder # - # above this one) must build a program that can invoke Nix at # - # runtime, with a derivation that needs a program tracked in this # - # source tree (`group-layers`). # - # # - # Simply installing that program in the $PATH of Nixery does not # - # work, because the runtime Nix builds use their own isolated # - # environment. # - # # - # I first attempted to naively copy the sources into the Nix # - # store, so that Nixery could build `group-layers` when it starts # - # up - however those sources are not available to a nested Nix # - # build because they're not part of the context of the nested # - # invocation. # - # # - # Nix has several primitives under `builtins.` that can break # - # evaluation purity, these (namely readDir and readFile) are used # - # below to break out of the isolated environment and reconstruct # - # the source tree for `group-layers`. # - # # - # There might be a better way to do this, but I don't know what # - # it is. # - # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # - src = runCommand "group-layers-srcs" { } '' - mkdir -p $out - ${with builtins; - let - files = - (attrNames (lib.filterAttrs (_: t: t != "symlink") (readDir self))); - commands = - map (f: "cp ${toFile f (readFile "${self}/${f}")} $out/${f}") files; - in lib.concatStringsSep "\n" commands} - ''; - - meta = { - description = - "Tool to group a set of packages into container image layers"; - license = lib.licenses.asl20; - maintainers = [ lib.maintainers.tazjin ]; - }; - }; - - buildImage = import ./build-image.nix - ({ inherit pkgs groupLayers; } // (lib.filterAttrs (_: v: v != null) args)); - - # Wrapper script which is called by the Nixery server to trigger an - # actual image build. This exists to avoid having to specify the - # location of build-image.nix at runtime. - wrapper = writeShellScriptBin "nixery-build-image" '' - exec ${nix}/bin/nix-build \ - --show-trace \ - --no-out-link "$@" \ - --argstr self "${./.}" \ - -A buildImage ${./.} - ''; -} +# This file builds a wrapper script called by Nixery to ask for the +# content information for a given image. +# +# The purpose of using a wrapper script is to ensure that the paths to +# all required Nix files are set correctly at runtime. + +{ pkgs ? import <nixpkgs> {} }: + +pkgs.writeShellScriptBin "nixery-build-image" '' + exec ${pkgs.nix}/bin/nix-build \ + --show-trace \ + --no-out-link "$@" \ + --argstr loadPkgs ${./load-pkgs.nix} \ + ${./build-image.nix} +'' |