74 lines
2.7 KiB
Nix
74 lines
2.7 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.
|
||
|
|
||
|
# Load a Nix package set from a source specified in one of the following
|
||
|
# formats:
|
||
|
#
|
||
|
# 1. nixpkgs!$channel (e.g. nixpkgs!nixos-19.03)
|
||
|
# 2. git!$repo!$rev (e.g. git!git@github.com:NixOS/nixpkgs.git!master)
|
||
|
# 3. path!$path (e.g. path!/var/local/nixpkgs)
|
||
|
#
|
||
|
# '!' was chosen as the separator because `builtins.split` does not
|
||
|
# support regex escapes and there are few other candidates. It
|
||
|
# doesn't matter much because this is invoked by the server.
|
||
|
{ pkgSource, args ? { } }:
|
||
|
|
||
|
with builtins;
|
||
|
let
|
||
|
# If a nixpkgs channel is requested, it is retrieved from Github (as
|
||
|
# a tarball) and imported.
|
||
|
fetchImportChannel = channel:
|
||
|
let
|
||
|
url =
|
||
|
"https://github.com/NixOS/nixpkgs-channels/archive/${channel}.tar.gz";
|
||
|
in import (fetchTarball url) args;
|
||
|
|
||
|
# If a git repository is requested, it is retrieved via
|
||
|
# builtins.fetchGit which defaults to the git configuration of the
|
||
|
# outside environment. This means that user-configured SSH
|
||
|
# credentials etc. are going to work as expected.
|
||
|
fetchImportGit = url: rev:
|
||
|
let
|
||
|
# builtins.fetchGit needs to know whether 'rev' is a reference
|
||
|
# (e.g. a branch/tag) or a revision (i.e. a commit hash)
|
||
|
#
|
||
|
# Since this data is being extrapolated from the supplied image
|
||
|
# tag, we have to guess if we want to avoid specifying a format.
|
||
|
#
|
||
|
# There are some additional caveats around whether the default
|
||
|
# branch contains the specified revision, which need to be
|
||
|
# explained to users.
|
||
|
spec = if (stringLength rev) == 40 then {
|
||
|
inherit url rev;
|
||
|
} else {
|
||
|
inherit url;
|
||
|
ref = rev;
|
||
|
};
|
||
|
in import (fetchGit spec) args;
|
||
|
|
||
|
# No special handling is used for paths, so users are expected to pass one
|
||
|
# that will work natively with Nix.
|
||
|
importPath = path: import (toPath path) args;
|
||
|
|
||
|
source = split "!" pkgSource;
|
||
|
sourceType = elemAt source 0;
|
||
|
in if sourceType == "nixpkgs" then
|
||
|
fetchImportChannel (elemAt source 2)
|
||
|
else if sourceType == "git" then
|
||
|
fetchImportGit (elemAt source 2) (elemAt source 4)
|
||
|
else if sourceType == "path" then
|
||
|
importPath (elemAt source 2)
|
||
|
else
|
||
|
throw ("Invalid package set source specification: ${pkgSource}")
|