tvl-depot/tools/nixery/default.nix
Vincent Ambo 948f308025 feat(build): Configure Nixery image builder to set up env correctly
When running Nix inside of a container image, there are several
environment-specific details that need to be configured appropriately.

Most importantly, since one of the recent Nix 2.x releases, sandboxing
during builds is enabled by default. This, however, requires kernel
privileges which commonly aren't available to containers.

Nixery's demo instance (for instance, hehe) is deployed on AppEngine
where this type of container configuration is difficult, hence this
change.

Specifically the following were changed:

* additional tools (such as tar/gzip) were introduced into the image
  because the builtins-toolset in Nix does not reference these tools
  via their store paths, which leads to them not being included
  automatically
* Nix sandboxing was disabled in the container image
* the users/groups required by Nix were added to the container setup.
  Note that these are being configured manually instead of via the
  tools from the 'shadow'-package, because the latter requires some
  user information (such as root) to be present already, which is not
  the case inside of the container
2019-07-24 17:46:39 +00:00

105 lines
3.4 KiB
Nix

# 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.
{ pkgs ? import <nixpkgs> {} }:
with pkgs;
rec {
# Go implementation of the Nixery server which implements the
# container registry interface.
#
# Users will usually not want to use this directly, instead see the
# 'nixery' derivation below, which automatically includes runtime
# data dependencies.
nixery-server = buildGoPackage {
name = "nixery-server";
# Technically people should not be building Nixery through 'go get'
# or similar (as other required files will not be included), but
# buildGoPackage requires a package path.
goPackagePath = "github.com/google/nixery";
goDeps = ./go-deps.nix;
src = ./.;
meta = {
description = "Container image build serving Nix-backed images";
homepage = "https://github.com/google/nixery";
license = lib.licenses.asl20;
maintainers = [ lib.maintainers.tazjin ];
};
};
# Nix expression (unimported!) which is used by Nixery to build
# container images.
nixery-builder = runCommand "build-registry-image.nix" {} ''
cat ${./build-registry-image.nix} > $out
'';
# Static files to serve on the Nixery index. This is used primarily
# for the demo instance running at nixery.appspot.com and provides
# some background information for what Nixery is.
nixery-static = runCommand "nixery-static" {} ''
mkdir $out
cp ${./static}/* $out
'';
# Wrapper script running the Nixery server with the above two data
# dependencies configured.
#
# In most cases, this will be the derivation a user wants if they
# are installing Nixery directly.
nixery-bin = writeShellScriptBin "nixery" ''
export NIX_BUILDER="${nixery-builder}"
export WEB_DIR="${nixery-static}"
exec ${nixery-server}/bin/nixery
'';
# Container image containing Nixery and Nix itself. This image can
# be run on Kubernetes, published on AppEngine or whatever else is
# desired.
nixery-image = let
# Wrapper script for the wrapper script (meta!) which configures
# the container environment appropriately.
#
# Most importantly, sandboxing is disabled to avoid privilege
# issues in containers.
nixery-launch-script = writeShellScriptBin "nixery" ''
set -e
export NIX_SSL_CERT_FILE=/etc/ssl/certs/ca-bundle.crt
mkdir /tmp
# Create the build user/group required by Nix
echo 'nixbld:x:30000:nixbld' >> /etc/group
echo 'nixbld:x:30000:30000:nixbld:/tmp:/bin/bash' >> /etc/passwd
# Disable sandboxing to avoid running into privilege issues
mkdir -p /etc/nix
echo 'sandbox = false' >> /etc/nix/nix.conf
exec ${nixery-bin}/bin/nixery
'';
in dockerTools.buildLayeredImage {
name = "nixery";
contents = [
bashInteractive
cacert
coreutils
nix
nixery-launch-script
gnutar
gzip
];
};
}