gradle2nix/gradle.nix

# This file is generated by gradle2nix.
#
# Example usage (e.g. in default.nix):
#
#     with (import <nixpkgs> {});
#     let
#       buildGradle = callPackage ./gradle.nix {};
#     in
#       buildGradle {
#         lockFile = ./gradle.lock;
#
#         src = ./.;
#
#         gradleFlags = [ "installDist" ];
#
#         installPhase = ''
#           mkdir -p $out
#           cp -r app/build/install/myproject $out
#         '';
#       }

{
  lib,
  stdenv,
  gradle,
  buildMavenRepo,
  writeText,
}:

let
  defaultGradle = gradle;
in

{
  # Path to the lockfile generated by gradle2nix (e.g. gradle.lock).
  lockFile ? null,
  pname ? "project",
  version ? null,
  enableParallelBuilding ? true,
  # The Gradle package to use. Default is 'pkgs.gradle'.
  gradle ? defaultGradle,
  # Arguments to Gradle used to build the project in buildPhase.
  gradleFlags ? [ "build" ],
  # Enable debugging for the Gradle build; this will cause Gradle to run
  # a debug server and wait for a JVM debugging client to attach.
  enableDebug ? false,
  # Additional code to run in the Gradle init script (init.gradle).
  extraInit ? "",
  # Override the default JDK used to run Gradle itself.
  buildJdk ? null,
  # Override functions which fetch dependency artifacts.
  # Keys in this set are URL schemes such as "https" or "s3".
  # Values are functions which take a dependency in the form
  # `{ urls, hash }` and fetch into the Nix store. For example:
  #
  #   {
  #     s3 = { name, urls, hash }: fetchs3 {
  #       s3url = builtins.head urls;
  #       # TODO This doesn't work without patching fetchs3 to accept SRI hashes
  #       inherit name hash;
  #       region = "us-west-2";
  #       credentials = {
  #         access_key_id = "foo";
  #         secret_access_key = "bar";
  #       };
  #     };
  #   }
  fetchers ? { },
  # Overlays for dependencies in the offline Maven repository.
  #
  # Acceps an attrset of dependencies (usually parsed from 'lockFile'), and produces an attrset
  # containing dependencies to merge into the final set.
  #
  # The attrset is of the form:
  #
  #   {
  #      "${group}:${module}:${version}" = <derivation>;
  #      # ...
  #   }
  #
  # A dependency derivation unpacks multiple source files into a single Maven-style directory named
  # "${out}/${groupPath}/${module}/${version}/", where 'groupPath' is the dependency group ID with dot
  # characters ('.') replaced by the path separator ('/').
  #
  # Examples:
  #
  # 1. Add or replace a dependency with a single JAR file:
  #
  #    (_: {
  #      "com.squareup.okio:okio:3.9.0" = fetchurl {
  #        url = "https://repo.maven.apache.org/maven2/com/squareup/okio/okio/3.9.0/okio-3.9.0.jar";
  #        hash = "...";
  #        downloadToTemmp = true;
  #        postFetch = "install -Dt $out/com/squareup/okio/okio/3.9.0/ $downloadedFile"
  #      };
  #    })
  #
  # 2. Remove a dependency entirely:
  #
  #    # This works because the result is filtered for values that are derivations.
  #    (_: {
  #      "org.apache.log4j:core:2.23.1" = null;
  #    })
  overlays ? [ ],
  ...
}@args:

let
  inherit (builtins) removeAttrs;

  inherit (lib) versionAtLeast versionOlder;

  offlineRepo = buildMavenRepo {
    inherit
      lockFile
      pname
      version
      fetchers
      overlays
      ;
  };

  initScript = writeText "init.gradle" ''
    import org.gradle.util.GradleVersion

    static boolean versionAtLeast(String version) {
        return GradleVersion.current() >= GradleVersion.version(version)
    }

    static void configureRepos(RepositoryHandler repositories) {
        repositories.configureEach { ArtifactRepository repo ->
            if (repo instanceof MavenArtifactRepository) {
                repo.setArtifactUrls(new HashSet<URI>())
                repo.url 'file:${offlineRepo}'
                repo.metadataSources {
                    gradleMetadata()
                    mavenPom()
                    artifact()
                }
            } else if (repo instanceof IvyArtifactRepository) {
                repo.url 'file:${offlineRepo}'
                repo.layout('maven')
                repo.metadataSources {
                    gradleMetadata()
                    ivyDescriptor()
                    artifact()
                }
            } else if (repo instanceof UrlArtifactRepository) {
                repo.url 'file:/homeless-shelter'
            }
        }
    }

    beforeSettings { settings ->
        configureRepos(settings.pluginManagement.repositories)
        configureRepos(settings.buildscript.repositories)
        if (versionAtLeast("6.8")) {
            configureRepos(settings.dependencyResolutionManagement.repositories)
        }
    }

    beforeProject { project ->
        configureRepos(project.buildscript.repositories)
        configureRepos(project.repositories)
    }

    ${extraInit}
  '';

  buildGradlePackage = stdenv.mkDerivation (
    finalAttrs:
    {

      inherit
        buildJdk
        enableParallelBuilding
        enableDebug
        gradle
        gradleFlags
        pname
        version
        ;

      dontStrip = true;

      nativeBuildInputs = [ finalAttrs.gradle ];

      buildPhase =
        let
          finalGradleFlags =
            [
              "--console=plain"
              "--no-build-cache"
              "--no-configuration-cache"
              "--no-daemon"
              "--no-watch-fs"
              "--offline"
            ]
            ++ lib.optional (finalAttrs.buildJdk != null) "-Dorg.gradle.java.home=${finalAttrs.buildJdk.home}"
            ++ lib.optional finalAttrs.enableDebug "-Dorg.gradle.debug=true"
            ++ lib.optional finalAttrs.enableParallelBuilding "--parallel"
            ++ lib.optional (versionAtLeast finalAttrs.gradle.version "8.0") "--init-script=${initScript}"
            ++ finalAttrs.gradleFlags;
        in
        ''
          runHook preBuild

          (
          set -eux

          export NIX_OFFLINE_REPO='${offlineRepo}'
          export GRADLE_USER_HOME="$(mktemp -d)"

          ${lib.optionalString (versionOlder finalAttrs.gradle.version "8.0") ''
            # Work around https://github.com/gradle/gradle/issues/1055
            mkdir -p "$GRADLE_USER_HOME/init.d"
            ln -s ${initScript} "$GRADLE_USER_HOME/init.d/nix-init.gradle"
          ''}

          gradle ${builtins.toString finalGradleFlags}
          )

          runHook postBuild
        '';

      passthru = {
        inherit offlineRepo;
      };
    }
    // removeAttrs args [
      "lockFile"
      "extraInit"
      "fetchers"
      "overlays"
    ]
  );
in
buildGradlePackage