legacy-bazel.md

Usage from older Bazel

See instructions below for installation and use of rules_graalvm on Bazel 4 or older, via the WORKSPACE file:

Installation in WORKSPACE.bazel

If you don't want to use Bzlmod, you can install in a WORKSPACE manually:

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

http_archive(
    # ... paste this part from the github releases page ... #
)

load("@rules_graalvm//graalvm:repositories.bzl", "graalvm_repository")

graalvm_repository(
    name = "graalvm",         # anything you want
    version = "20.0.1",       # exact version of a GraalVM CE or Oracle GVM release
    distribution = "oracle",  # required for newer GVM releases (`oracle`, `ce`, or `community`)
    java_version = "20",      # java language version to use/declare
)

Building native images

When building a native image on Bazel 4, make sure to import the legacy rule:

load(
    "@rules_graalvm//graal:graal.bzl",
    "native_image",
)

Note the import from graal:graal.bzl instead of from graalvm/native_image:rules.bzl. This version of the rule is designed to work with older versions of Bazel, and this import exactly matches the import provided by the rules_graal package.

Continuing the example:

java_library(
    name = "java",
    srcs = ["Main.java"],
)

java_binary(
    name = "main",
    main_class = "Main",
    runtime_deps = [
        ":java",
    ],
)

native_image(
    name = "main-native",
    main_class = "Main",
    deps = [":java"],
)

alias(
    name = "sample",
    actual = "main-native",
)

No support for toolchains

Because older versions of Bazel don't support optional toolchains, there is no support for using GraalVM Native Image through that mechanism. You can still customize the Native Image tool used to build your binary:

native_image(
    name = "main-native",
    main_class = "Main",
    deps = [":java"],
    native_image_tool = "@some_other_graalvm_repository//:native-image",
)

Hard-coded repository name default

Note that the native_image_tool default value uses the @graalvm repository name for accessing the native-image tool. If you don't want it to do this, you must provide your own value. Non-legacy versions of this rule support toolchains; see usage from modern Bazel.