`rules_proto`

Bazel skylark rules for building protocol buffers +/- gRPC :sparkles:.

These rules are the successor to https://github.com/pubref/rules_protobuf and are in a pre-release status. The primary goals are:

Interoperate with the native proto_library rules and other proto support in the bazel ecosystem as much as possible.
Provide a proto_plugin rule to support custom protoc plugins.
Minimal dependency loading. Proto rules should not pull in more dependencies than they absolutely need.

NOTE: These rules are in a pre-release state. The routeguide examples have been developed thus far with the goal of getting them to compile/build, not to ensure the routeguide client/server is actually correct. Do expect everything to compile, but not to work right!

Usage

Add rules_proto your WORKSPACE:

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

http_archive(
    name = "build_stack_rules_proto",
    urls = ["https://github.com/stackb/rules_proto/archive/v0.9.tar.gz"],
    sha256 = 4329663fe6c523425ad4d3c989a8ac026b04e1acedeceb56aa4b190fa7f3973d,
    strip_prefix = "rules_proto-v0.9",
)

Follow instructions in the language-specific README.md for additional workspace dependencies and build rule usage.

Rules

Lang	Rule	Description
cpp	cpp_proto_compile	Generates .h,.cc protobuf artifacts
cpp	cpp_grpc_compile	Generates .h,.cc protobuf+gRPC artifacts
cpp	cpp_proto_library	Generates .h,.cc protobuf library
cpp	cpp_grpc_library	Generates .h,.cc protobuf+gRPC library
closure	closure_proto_compile	Generates closure *.js protobuf+gRPC files
closure	closure_proto_library	Generates a closure_library with compiled protobuf *.js files
node	node_proto_compile	Generates node *.js protobuf artifacts
node	node_grpc_compile	Generates node *.js protobuf+gRPC artifacts
node	node_proto_library	Generates node *.js protobuf library
node	node_grpc_library	Generates node *.js protobuf+gRPC library
java	java_proto_compile	Generates a srcjar with protobuf *.java files
java	java_grpc_compile	Generates a srcjar with protobuf+gRPC *.java files
java	java_proto_library	Generates a jar with compiled protobuf *.class files
java	java_grpc_library	Generates a jar with compiled protobuf+gRPC *.class files
scala	scala_proto_compile	Generates *.scala protobuf artifacts
scala	scala_grpc_compile	Generates *.scala protobuf+gRPC artifacts
scala	scala_proto_library	Generates *.py protobuf library
scala	scala_grpc_library	Generates *.py protobuf+gRPC library
python	python_proto_compile	Generates *.py protobuf artifacts
python	python_grpc_compile	Generates *.py protobuf+gRPC artifacts
python	python_proto_library	Generates *.py protobuf library
python	python_grpc_library	Generates *.py protobuf+gRPC library
go	go_proto_compile	Generates *.go protobuf artifacts
go	go_grpc_compile	Generates *.go protobuf+gRPC artifacts
go	go_proto_library	Generates *.go protobuf library
go	go_grpc_library	Generates *.go protobuf+gRPC library
ruby	ruby_proto_compile	Generates *.ruby protobuf artifacts
ruby	ruby_grpc_compile	Generates *.ruby protobuf+gRPC artifacts
ruby	ruby_proto_library	Generates *.rb protobuf library
ruby	ruby_grpc_library	Generates *.rb protobuf+gRPC library
objc	objc_proto_compile	Generates objc protobuf artifacts
objc	objc_grpc_compile	Generates objc protobuf+gRPC artifacts
php	php_proto_compile	Generates php protobuf artifacts
php	php_grpc_compile	Generates php protobuf+gRPC artifacts
rust	rust_proto_compile	Generates rust protobuf artifacts
rust	rust_grpc_compile	Generates rust protobuf+gRPC artifacts
rust	rust_proto_library	Generates rust protobuf library
rust	rust_grpc_library	Generates rust protobuf+gRPC library
dart	dart_proto_compile	Generates dart protobuf artifacts
dart	dart_grpc_compile	Generates dart protobuf+gRPC artifacts
dart	dart_proto_library	Generates dart protobuf library
dart	dart_grpc_library	Generates dart protobuf+gRPC library
grpc_web	closure_grpc_compile	Generates a closure *.js protobuf+gRPC files
grpc_web	commonjs_grpc_compile	Generates a commonjs *.js protobuf+gRPC files
grpc_web	commonjs_dts_grpc_compile	Generates a commonjs_dts *.js protobuf+gRPC files
grpc_web	ts_grpc_compile	Generates a commonjs *.ts protobuf+gRPC files
gogo	gogo_proto_compile	Generates gogo protobuf artifacts
gogo	gogo_grpc_compile	Generates gogo protobuf+gRPC artifacts
gogo	gogo_proto_library	Generates gogo protobuf library
gogo	gogo_grpc_library	Generates gogo protobuf+gRPC library
gogo	gogofast_proto_compile	Generates gogofast protobuf artifacts
gogo	gogofast_grpc_compile	Generates gogofast protobuf+gRPC artifacts
gogo	gogofast_proto_library	Generates gogofast protobuf library
gogo	gogofast_grpc_library	Generates gogofast protobuf+gRPC library
gogo	gogofaster_proto_compile	Generates gogofaster protobuf artifacts
gogo	gogofaster_grpc_compile	Generates gogofaster protobuf+gRPC artifacts
gogo	gogofaster_proto_library	Generates gogofaster protobuf library
gogo	gogofaster_grpc_library	Generates gogofaster protobuf+gRPC library

Code Layout

Each language {lang} has a top-level subdirectory that contains:

{lang}/README.md: generated documentation for the rule(s).
{lang}/deps.bzl: contains macro functions that declare repository rule dependencies for that language. The name of the macro corresponds to the name of the build rule you'd like to use.
{lang}/{rule}.bzl: rule implementation(s) of the form {lang}_{kind}_{type}, where kind is one of proto|grpc and type is one of compile|library.
{lang}/BUILD.bazel: contains proto_plugin() declarations for the available plugins for that language.
{lang}/example/{rule}/: contains a generated WORKSPACE and BUILD.bazel demonstrating standalone usage.
{lang}/example/routeguide/: routeguide example implementation, if possible.

The root directory contains the base rule defintions:

plugin.bzl: A build rule that defines the name, tool binary, and options for a particular proto plugin.
compile.bzl: A build rule that contains the proto_compile rule. This rule calls protoc with a given list of plugins and generates output files.

Additional protoc plugins and their rules are scoped to the github repository name where the plugin resides. For example, there are 3 grpc-web implementations in this repo: `github.com/improbable-eng/grpc-web, github.com/grpc/grpc-web, and github.com/stackb/grpc.js.

Developing Custom Plugins

Follow the pattern seen in the multiple examples in this repository. The basic idea is:

Load the plugin rule: load("@build_stack_rules_proto//:plugin.bzl", "proto_plugin").
Define the rule, giving it a name, options (not mandatory), tool, and outputs.
tool is a label that refers to the binary executable for the plugin itself.
outputs is a list of strings that predicts the pattern of files generated by the plugin. Specifying outputs is the only attribute that requires much mental effort. [TODO: article here with example writing a custom plugin].

Contributing

Contributions welcome; please create Issues or GitHub pull requests.