6262dec8aa
This introduces a new Nix derivation that, given an attribute set of layer hashes mapped to store paths, will create a layer tarball for each of the store paths. This is going to be used by the builder to create layers that are not present in the cache. Relates to #50.
47 lines
1.5 KiB
Nix
47 lines
1.5 KiB
Nix
# Copyright 2019 Google LLC
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# https://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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{
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# Description of the package set to be used (will be loaded by load-pkgs.nix)
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srcType ? "nixpkgs",
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srcArgs ? "nixos-19.03",
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importArgs ? { },
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# Path to load-pkgs.nix
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loadPkgs ? ./load-pkgs.nix,
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# Layers to assemble into tarballs
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layers ? "{}"
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}:
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let
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inherit (builtins) fromJSON mapAttrs toJSON;
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inherit (pkgs) lib runCommand;
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pkgs = import loadPkgs { inherit srcType srcArgs importArgs; };
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# Given a list of store paths, create an image layer tarball with
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# their contents.
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pathsToLayer = paths: runCommand "layer.tar" {
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} ''
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tar --no-recursion -Prf "$out" \
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--mtime="@$SOURCE_DATE_EPOCH" \
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--owner=0 --group=0 /nix /nix/store
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tar -Prpf "$out" --hard-dereference --sort=name \
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--mtime="@$SOURCE_DATE_EPOCH" \
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--owner=0 --group=0 ${lib.concatStringsSep " " paths}
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'';
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layerTarballs = mapAttrs (_: pathsToLayer ) (fromJSON layers);
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in writeText "layer-tarballs.json" (toJSON layerTarballs)
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