Bazel Dependencies Plugin

A Gradle plugin that allows the generation of Bazel repository rules from Gradle project dependency configuration.

Features:

• Generates jvm_import_external rules with transitive dependencies mapped to compile and runtime scopes
• Wraps generated rules in a function which allows per-dependency exclusion and replacement in the Bazel project
• Generates rules_jvm_external artifact list, respecting Gradle dependency exclusion rules, and supporting optional version pinning (maven_install.json)
• Allows re-hashing the pinned maven_install.json file after manual modifications (e.g. to replace URLs)
• Detects multiple repository URLs for artifact availability

Compatibility & upgrade notes

• Version 3.0.0 refactors the dependency tree calculation, and tracks usage scope (api/runtime). This is currently used in jvm_import_external attributes, but is not supported by rules_jvm_external. Dependency cycles are now detected and cause an error, but may be handled by transitive dependency exclusions, which are now propagated from the Gradle project to the generated Bazel configuration.

  Breaking changes:

  • The Gradle project extension (configuration API) has been refactored and will likely require changes in your project.
  • Dependency source artifact resolution is now included by default, and cannot be disabled.
  • Dependency license detection is no longer provided and license attributes are no longer set (per the Bazel docs "This is part of a deprecated licensing API that Bazel no longer uses. Don't use this.").

• Version 2.3.0 adds support for the new lockfile format in rules_jvm_external version 5.0.

• Version 2.2.1 adds support for the new lockfile hashing in rules_jvm_external version 4.3.

• Version 2.1.0 supports Gradle ≥ 7.4, and supports more flexible compileOnly/testOnly matching by optionally omitting dependency versions.

• Version 2.0.0 adds support for the new checksum format introduced in rules_jvm_external. This is managed with a new property to describe the version of the rules dependency:

  bazelDependencies {
    rulesJvmExternalVersion.set("4.1.0")
  }

  Additionally, configuration of the com.github.jk1.dependency-license-report plugin is pulled from the project if the plugin is already applied, enabling some tweaking of the discovered license data.

• Version 1.8.0 contains breaking changes: properties in the bazelDependencies use the Gradle Property syntax, instead of assignment.

  Replace configuration like

  bazelDependencies {
    configuration = generate
    outputFile = project.buildDir.resolve("java_repositories.bzl")
    strictLicenses = true
  }

  with

  bazelDependencies {
    configuration.set(generate)
    outputFile.set(project.buildDir.resolve("java_repositories.bzl"))
    strictLicenses.set(true)
  }

  This version also removes the mode parameter in favour of explicit task naming. The JVM_MAVEN_IMPORT_EXTERNAL mode now corresponds to the generateJvmMavenImportExternal task, while RULES_JVM_EXTERNAL is replaced by generateRulesJvmExternal.

  This version adds support for rehashing the version pinning file maven_install.json, with a new task: rehashMavenInstall.

• Version 1.5.0 provides initial support for rules_jvm_external. This includes the generation of the artifact list for a complete dependency closure, evaluated by gradle, which therefore enables support for maven BOMs and custom dependency resolution behaviour.

  The call to maven_install should specify version_conflict_policy = "pinned" to ensure coursier does not resolve dependencies outside this closure.

• Version 1.1.0 is compatible with Bazel >= 0.23.0 as it generates jvm_maven_import_external rules making use of the fetch_sources attribute which did not exist prior to this version.

• Version 1.0.0 of the plugin should be compatible with most Bazel versions.

Usage

Applying the plugin provides three tasks:

• generateJvmMavenImportExternal
• generateRulesJvmExternal
• rehashMavenInstall

The plugin exposes some mandatory configuration parameters to be defined in build.gradle in a bazelDependencies block:

• configuration: The project configuration providing dependencies to be resolved
• outputFile: The target file for the Bazel repository rules function

Running the generateJvmMavenImportExternal task will walk the configuration's dependency tree, detect valid repository URLs, determine the most restrictive applicable licenses, and emit a file which can be loaded in a Bazel WORKSPACE.

Running the generateRulesJvmExternal task will walk the configuration's dependency tree and emit a complete list of all dependency versions, suitable for loading into the artifacts attribute of the maven_install repository rule from rules_jvm_external. The maven_install.json artifact lock file can optionally be generated, with correct checksums and valid URLs for each dependency.

Optional configuration parameters

• neverlink (default empty set): A Set<String> of artifact identifiers for which the Bazel targets should be marked neverlink = True, i.e. available only on the compilation classpath, and not at runtime. Currently only functional with generateRulesJvmExternal.
• testonly (default empty set): A Set<String> of artifact identifiers for which the Bazel targets should be marked testonly = True, i.e. available only to targets which are themselves testonly, for example to avoid leaking test libraries into production artifacts. Currently only functional with generateRulesJvmExternal, and the testonly attribute is only supported by rules_jvm_external > 3.1.
• jvmImportExternal.createAggregatorRepo (default true): If true, an aggregate repository rule is created with all imported dependencies, to provide consistency with the rules_jvm_external approach. A dependency available at @com_example_somedep will be additionally aliased from @maven//:com_example_somedep. The name of this rule (maven) may be set when instantiating the repo in the Bazel WORKSPACE file.
• rulesJvmExternal.version (default "6.0"): A String describing the target version of rules_jvm_external. This controls the output format of maven_install.json.
• rulesJvmExternal.createMavenInstallJson (default true): If true, the generateRulesJvmExternal task creates a maven_install.json lock file alongside the java_repositories.bzl file. This JSON file is intended to be usable with the maven_install_json attribute of maven_install from rules_jvm_external, for pinned versioning and faster and cacheable resolution of Maven dependencies.

Example (kotlin-dsl)

plugins {
    `java-base`
    id("com.github.zetten.bazel-dependencies-plugin")
}

repositories {
    mavenCentral()
}

val generate by configurations.creating {
    attributes {
        attribute(Bundling.BUNDLING_ATTRIBUTE, objects.named(Bundling.EXTERNAL))
    }
}

dependencies {
    generate(enforcedPlatform("io.grpc:grpc-bom:1.61.0"))
    generate("io.grpc:grpc-core") {
        exclude("io.grpc", "grpc-util")
    }
    generate("com.google.guava:guava:33.0.0-jre")
}

bazelDependencies {
    configuration = generate
    outputFile = project.layout.buildDirectory.file("java_repositories.bzl")
    rulesJvmExternal {
        version = "5.0"
    }
}