feat(nix): Add derivation to create layer tars from a store path set

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.
This commit is contained in:
Vincent Ambo 2019-09-30 14:19:11 +01:00 committed by Vincent Ambo
parent 2c8ef634f6
commit 6262dec8aa
3 changed files with 69 additions and 9 deletions

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@ -0,0 +1,47 @@
# Copyright 2019 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
{
# Description of the package set to be used (will be loaded by load-pkgs.nix)
srcType ? "nixpkgs",
srcArgs ? "nixos-19.03",
importArgs ? { },
# Path to load-pkgs.nix
loadPkgs ? ./load-pkgs.nix,
# Layers to assemble into tarballs
layers ? "{}"
}:
let
inherit (builtins) fromJSON mapAttrs toJSON;
inherit (pkgs) lib runCommand;
pkgs = import loadPkgs { inherit srcType srcArgs importArgs; };
# Given a list of store paths, create an image layer tarball with
# their contents.
pathsToLayer = paths: runCommand "layer.tar" {
} ''
tar --no-recursion -Prf "$out" \
--mtime="@$SOURCE_DATE_EPOCH" \
--owner=0 --group=0 /nix /nix/store
tar -Prpf "$out" --hard-dereference --sort=name \
--mtime="@$SOURCE_DATE_EPOCH" \
--owner=0 --group=0 ${lib.concatStringsSep " " paths}
'';
layerTarballs = mapAttrs (_: pathsToLayer ) (fromJSON layers);
in writeText "layer-tarballs.json" (toJSON layerTarballs)

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@ -20,10 +20,20 @@
{ 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}
''
{
build-image = pkgs.writeShellScriptBin "nixery-build-image" ''
exec ${pkgs.nix}/bin/nix-build \
--show-trace \
--no-out-link "$@" \
--argstr loadPkgs ${./load-pkgs.nix} \
${./build-image.nix}
'';
build-layers = pkgs.writeShellScriptBin "nixery-build-layers" ''
exec ${pkgs.nix}/bin/nix-build \
--show-trace \
--no-out-link "$@" \
--argstr loadPkgs ${./load-pkgs.nix} \
${./build-layers.nix}
'';
}

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@ -11,13 +11,15 @@
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
{ pkgs ? import <nixpkgs> { }
, preLaunch ? ""
, extraPackages ? [] }:
with pkgs;
rec {
let builders = import ./build-image { inherit pkgs; };
in rec {
# Go implementation of the Nixery server which implements the
# container registry interface.
#
@ -27,7 +29,8 @@ rec {
nixery-server = callPackage ./server { };
# Implementation of the Nix image building logic
nixery-build-image = import ./build-image { inherit pkgs; };
nixery-build-image = builders.build-image;
nixery-build-layers = builders.build-layers;
# Use mdBook to build a static asset page which Nixery can then
# serve. This is primarily used for the public instance at