BUILD.pants

# This target invokes Bazel to produce a jar file. The example is contrived since Pants has JVM support,
# but the main focal point here is demonstrating Pants invoking a third party build tool and then
# consuming that tool's output (and not the particular details of this example).
#
# Please note that the `{chroot}` symbol is replaced with the path to a temporary directory created
# during execution to materialize Pants-supplied inputs.
#
# Moreover, the `{chroot}` directory is also used by Pants for capturing outputs from this process. (Thus,
# the jar file is copied to the `{chroot}` directory to make it visible to Pants.)
shell_command(
  name="bazel-jvm-binary",
  command="bazel build --java_runtime_version=remotejdk_11 :ProjectRunner && cp bazel-bin/ProjectRunner.jar {chroot} && ls {chroot}",
  tools=["bazel", "gcc", "cp", "ls"],
  extra_env_vars=["HOME", "PATH"],
  workdir="bazel-jvm",
  output_files=["ProjectRunner.jar"],

  # This field sets what environment to execute the command in. The special value
  # `__local_workspace__` selects whatever configured `experimental_workspace_environment`
  # matches the current platform.
  environment="__local_workspace__",

  # The `path_env_modify` field allows you to disable modification of the PATH environment
  # variable by Pants. Since Bazel incorporates the exact PATH value into its cache
  # keys, this allows Bazel to actually use its cache (versus having to rebuild everything each 
  # time since the PATH will differ).
  path_env_modify="off",

  # Configure a longer timeout to give Bazel a chance to complete when necessary.
  timeout=600,
)

# Build a Docker image which embeds the jar produced by Bazel via the //:bazel-jvm-binary target.
# Note: The jar file is visible to this target because it is listed as a dependency.
docker_image(
  name="project_image",
  instructions=[
    "FROM openjdk:24-jdk-slim-bullseye",
    "WORKDIR /app",
    "COPY ProjectRunner.jar .",
    'ENTRYPOINT ["java", "-cp", "ProjectRunner.jar", "com.example.ProjectRunner"]',
  ],
  dependencies=[
    ":bazel-jvm-binary",
  ],
)

# This target configures in-workspace execution support. A few points of note:
# 1. This target accepts all of the same fields as any other environment target. Thus, you may customize various Pants options for just this environment.
# 2. The target address of this target must be configured in `environments-preview.names` section of `pants.toml` to be usable.
experimental_workspace_environment(
  name="workspace",
)