bazel-multiversion

Transitive Maven artifact resolution that supports multiple versions of the same 3rdparty dependency (an alternative to bazelbuild/rules_jvm_external).

Getting started

# Step 1: Clone repo
git clone https://github.com/twitter/bazel-multiversion
cd bazel-multiversion

# Step 2: Build and run code with different versions of Guava
cd multiversion-example/
bazel build tricky/...
bazel run tricky/user/src/main/scala/bincompat:bin-needs-guava24
bazel run tricky/user/src/main/scala/bincompat:bin-needs-guava29

Usage

Download GraalVM native image from https://github.com/twitter/bazel-multiversion/releases, and put multiversion in your PATH.

There are 3 ways to configure the dependencies.

BUILDish DSL

BUILDish DSL allows the configuration of dependencies using BUILD files similar to what is currently done using Pants. See multiversion-example/3rdparty/jvm/ for the examples.

To regenerate the 3rdparty/jvm_deps.bzl file, run the following inside the multiversion-example/ directory:

$ multiversion import-build --output-path=3rdparty/jvm_deps.bzl

multiversion_config

Place this at 3rdparty/jvm/BUILD:

multiversion_config(
  scala_versions = ["2.12.12"],
)

Currently only one Scala version can be specified.

jar_library

Place BUILD files under 3rdparty/jvm/com/google/guava/BUILD where com/google/guava matches the groupid of the external library:

jar_library(
  name = "guava",
  jars = [
    jar(
      org = "com.google.guava",
      name = "guava",
      rev = "29.0-jre",
    )
  ],
)

jar_library(
  name = "guava-24",
  jars = [
    jar(
      org = "com.google.guava",
      name = "guava",
      rev = "24.1.1-jre",
    ),
    jar(
      org = "org.checkerframework",
      name = "checker-compat-qual",
      rev = "2.0.0",
    )
  ],
)

For Scala libraries:

jar_library(
  name = "scalameta",
  jars = [
    scala_jar(
      org = "org.scalameta",
      name = "scalameta",
      rev = "4.0.0",
    )
  ],
)

Next, reference the artifacts in the BUILD file with their label (location of the Guava BUILD + / + name of the "target"):

scala_library(
    name="hello",
    srcs=["Hello.scala"],
    deps=[
        "@maven//:3rdparty/jvm/com/google/guava/guava",
    ],
)

Workspace setup

load("//3rdparty:jvm_deps.bzl", "jvm_deps")
jvm_deps()
load("@maven//:jvm_deps.bzl", "load_jvm_deps")
load_jvm_deps()

YAML or JSON

If you prefer to configure the dependencies in one file, create 3rdparty.yaml at the root of monorepo instead To regenerate the 3rdparty/jvm_deps.bzl file, runt the following inside the multiversion-example/ directory:

$ multiversion export --output-path=3rdparty/jvm_deps.bzl

You can also specify a different path or format for the input configuration using --input-path:

$ multiversion export --input-path=config/3rdparty.json --output-path=3rdparty/jvm_deps.bzl

Pants

$ multiversion pants-export --output-path=3rdparty/jvm_deps.bzl

Publishing to external repositories

See rules_jvm_export.

Building from source

See DEVELOP.

License

Copyright Twitter, Inc.

Licensed under the Apache License, Version 2.0