Rules

proto_compile

Coordinates the exection of protoc and associated plugins.

Example:

proto_compile(
    name = "example_java_compile",
    outs = {"@build_stack_rules_proto//plugin/builtin:java": "example.srcjar"},
    outputs = ["example.srcjar"],
    plugins = ["@build_stack_rules_proto//plugin/builtin:java"],
    proto = "example_proto",
)

proto_compile attribute	type	description
plugins	label_list	list of upstream proto_plugin rules (ProtoPluginInfo provider)
option	label_keyed_string_list	List of options, grouped by plugin
outs	label_keyed_string_list	Output location for generated files, grouped by plugin. By default, the bazel execroot used.
outputs	output_list	List of files that to be generated.
mappings	label_keyed_string_list	Mapping from execroot-relative path to package-relative path (^1).
srcs	string_list	List of source files expected to be generated. Only one of srcs or outputs should be specified.
proto	label	upstream proto_library rule (ProtoInfo provider)
verbose	bool	If true, the full command args, expected outputs, and pre-/post- state of sandbox are printed.

^1: bazel mandates that any file produced by an action is created within its respective package path of the sandbox. For example, consider a file proto/example.proto that contains a go_package option github.com/foo/bar. In this case the generated execroot-relative location will be ./github.com/foo/bar/example.pb.go, which is not inside proto/. The mapping option provides a mechanism to schedule a file copy operation cp /github.com/foo/bar/example.pb.go ./proto/example.pb.go in order to satify bazel action constraints.

proto_compiled_sources

The proto_compiled_sources rule is intended for the use case where generated files are checked into source control. While one can debate whether having generated files in the source tree is a bad idea, these files may need to remain in source control during a migration period or because reasons.

Example:

proto_compiled_sources(
    name = "v1_gogofast_compiled_sources",
    srcs = [
        "message.pb.go",
        "service.pb.go",
    ],
    output_mappings = [
        "message.pb.go=github.com/example/repo/api/v1/message.pb.go",
        "service.pb.go=github.com/example/repo/api/v1/service.pb.go",
    ],
    options = {"@build_stack_rules_proto//plugin/gogo/protobuf:protoc-gen-gogofast": ["plugins=grpc"]},
    plugins = ["@build_stack_rules_proto//plugin/gogo/protobuf:protoc-gen-gogofast"],
    proto = "v1_proto",
    visibility = ["//proto:__subpackages__"],
)

A proto_compiled_sources rule named //proto/api/v1:v1_gogofast_compiled_sources is a macro that has three targets:

• bazel build //proto/api/v1:v1_gogofast_compiled_sources generates files in the bazel-out/ directory.
• bazel run //proto/api/v1:v1_gogofast_compiled_sources.update generates files in the bazel-out/ directory and copies them back into the source package.
• bazel test //proto/api/v1:v1_gogofast_compiled_sources_test asserts equality between the source file(s) and the generated file(s).

The _test target ensures that changes made to source .proto file will not pass CI unless the .update target has been run, preventing drift.

This rule has nearly identical attributes as proto_compile, but the srcs attribute is used rather than outputs.

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