Allow greater customization of environment variables by plugins.

[gonzojive]

• Add an "env" property to ProtoPluginInfo that contains an environment variable dictionary.

• Add a corresponding "env" attribute to the the proto_plugin rule.

• For cases where environment variables must specified based on ctx, as described in Always expose ctx.var["BINDIR"] to actions bazelbuild/bazel#15470 and Demonstrate usage with protocol buffers and grpc aspect-build/rules_js#397, modify proto_compile_impl and proto_compile to accept a base_env dictionary argument. Example usage is below:

def _ts_proto_compile_impl(ctx):
    """
    Implementation function for ts_proto_compile.

    Args:
        ctx: The Bazel rule execution context object.

    Returns:
        Providers:
            - ProtoCompileInfo
            - DefaultInfo

    """
    base_env = {
        # Make up for https://github.com/bazelbuild/bazel/issues/15470.
        "BAZEL_BINDIR": ctx.bin_dir.path,
    }
    return proto_compile_impl(ctx, base_env = base_env)

ts_proto_compile = rule(
    implementation = _ts_proto_compile_impl,
    attrs = dict(
        proto_compile_attrs,
        _plugins = attr.label_list(
            providers = [ProtoPluginInfo],
            default = [
                Label("//bazel/web/targets:ts_proto_compile"),
            ],
            doc = "List of protoc plugins to apply",
        ),
    ),
    toolchains = [
        str(Label("@rules_proto_grpc//protobuf:toolchain_type")),
    ],
)

load("@npm//:ts-proto/package_json.bzl", _ts_proto_bin_factories = "bin")
load("@rules_proto_grpc//:defs.bzl", "proto_plugin")

_ts_proto_bin_factories.protoc_gen_ts_proto_binary(
    name = "protoc-gen-ts-proto",
)

proto_plugin(
    name = "ts_proto_compile",
    outputs = ["{protopath}.ts"],
    protoc_plugin_name = "ts_proto",
    tool = "//bazel/web/targets:protoc-gen-ts-proto",
    use_built_in_shell_environment = False,
    visibility = ["//visibility:public"],
)

[aaliddell]

Seems reasonable, thanks. The doc_template_compile_impl needs fixing, but I'll merge to dev and fix it there for 4.3.0. I'd be interested to see the result of getting protoc-gen-ts-proto working with rules_js, as there's ongoing problems with getting typescript to work with rules_nodejs in this repo and I'd like to see if there's a viable alternative 👍

[aaliddell]

Ok, thanks for finding that reference. I'll take this now for 4.3.0 but will need a little rework to take the env from the plugin env attr as presently that is not checked