arion/nix/upstreamable/default.nix
2021-05-18 12:54:53 +02:00

91 lines
2.7 KiB
Nix

args@
{ pkgs
, lib
, haskellPackages
, haskell
, runCommand
# Allow this expression file to be used more efficiently in situations where
# the sources are more readily available. Unpacking haskellPackages.arion-compose.src
# is not always the best choice for arion.eval.
, evalSrc ? null
}:
let
/* This derivation builds the arion tool.
It is based on the arion-compose Haskell package, but adapted and extended to
- have the correct name
- have a smaller closure size
- have functions to use Arion from inside Nix: arion.eval and arion.build
- make it self-contained by including docker-compose
*/
arion =
justStaticExecutables (
overrideCabal
arion-compose
cabalOverrides
);
inherit (haskell.lib) justStaticExecutables overrideCabal;
inherit (haskellPackages) arion-compose;
cabalOverrides = o: {
buildTools = (o.buildTools or []) ++ [pkgs.makeWrapper];
passthru = (o.passthru or {}) // {
inherit eval build;
};
# Patch away the arion-compose name. Unlike the Haskell library, the program
# is called arion (arion was already taken on hackage).
pname = "arion";
src = arion-compose.src;
# PYTHONPATH
#
# We close off the python module search path!
#
# Accepting directories from the environment into the search path
# tends to break things. Docker Compose does not have a plugin
# system as far as I can tell, so I don't expect this to break a
# feature, but rather to make the program more robustly self-
# contained.
postInstall = ''${o.postInstall or ""}
mkdir -p $out/libexec
mv $out/bin/arion $out/libexec
makeWrapper $out/libexec/arion $out/bin/arion \
--unset PYTHONPATH \
--prefix PATH : ${lib.makeBinPath [ pkgs.docker-compose ]} \
;
'';
};
# Unpacked sources for evaluation by `eval`
evalSrc' = args.evalSrc or (runCommand "arion-src" {}
"mkdir $out; tar -C $out --strip-components=1 -xf ${arion-compose.src}");
/* Function for evaluating a composition
Re-uses this Nixpkgs evaluation instead of `arion-pkgs.nix`.
Returns the module system's `config` and `options` variables.
*/
eval = args@{...}:
import (evalSrc' + "/src/nix/eval-composition.nix")
({ inherit pkgs; } // args);
/* Function to derivation of the docker compose yaml file
NOTE: The output will change: https://github.com/hercules-ci/arion/issues/82
This function is particularly useful on CI. On Nixpkgs >= 20.09 this will
not store the image tarballs but executables to produce them reliably via
streamLayeredImage.
*/
build = args@{...}:
let composition = eval args;
in composition.config.out.dockerComposeYaml;
in arion