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authorVincent Ambo <tazjin@google.com>2019-09-29T21·58+0100
committerVincent Ambo <github@tazj.in>2019-10-03T12·21+0100
commit0898d8a96175958b82d1713d13304423f8b19f77 (patch)
tree9e4c1f454dd2d4fe32efe825740aeb504bd7678d /tools/nixery/build-image/default.nix
parent712b38cbbcb5671135dbf04492de3c4e97fa1b87 (diff)
chore(build-image): Simplify wrapper build & remove layer grouping
Simplifies the wrapper script used to invoke Nix builds from Nixery to
just contain the essentials, since the layer grouping logic is moving
into the server itself.
Diffstat (limited to 'tools/nixery/build-image/default.nix')
-rw-r--r--tools/nixery/build-image/default.nix96
1 files changed, 15 insertions, 81 deletions
diff --git a/tools/nixery/build-image/default.nix b/tools/nixery/build-image/default.nix
index 3bb5d62fb0d5..a61ac06bdd92 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}
+''