Protocol Buffer Rules

Rules

• proto_lang_toolchain
• proto_library

proto_lang_toolchain

proto_lang_toolchain(name, blacklisted_protos, command_line, compatible_with, deprecation, distribs, exec_compatible_with, exec_properties, features, licenses, mnemonic, output_files, plugin, plugin_format_flag, progress_message, proto_compiler, restricted_to, runtime, tags, target_compatible_with, testonly, visibility)

If using Bazel, please load the rule from https://github.com/bazelbuild/rules_proto.

Specifies how a LANG_proto_library rule (e.g., java_proto_library) should invoke the proto-compiler. Some LANG_proto_library rules allow specifying which toolchain to use using command-line flags; consult their documentation.

Normally you should not write those kind of rules unless you want to tune your Java compiler.

There's no compiler. The proto-compiler is taken from the proto_library rule we attach to. It is passed as a command-line flag to Blaze. Several features require a proto-compiler to be invoked on the proto_library rule itself. It's beneficial to enforce the compiler that LANG_proto_library uses is the same as the one proto_library does.

Examples

A simple example would be:

proto_lang_toolchain(
    name = "javalite_toolchain",
    command_line = "--javalite_out=shared,immutable:$(OUT)",
    plugin = ":javalite_plugin",
    runtime = ":protobuf_lite",
)

Arguments

proto_library

proto_library(name, deps, srcs, data, allow_exports, compatible_with, deprecation, distribs, exec_compatible_with, exec_properties, exports, features, import_prefix, licenses, restricted_to, strip_import_prefix, tags, target_compatible_with, testonly, visibility)

Deprecated. Please use https://github.com/bazelbuild/rules_proto instead.

Use proto_library to define libraries of protocol buffers which may be used from multiple languages. A proto_library may be listed in the deps clause of supported rules, such as java_proto_library.

When compiled on the command-line, a proto_library creates a file named foo-descriptor-set.proto.bin, which is the descriptor set for the messages the rule srcs. The file is a serialized FileDescriptorSet, which is described in https://developers.google.com/protocol-buffers/docs/techniques#self-description.

It only contains information about the .proto files directly mentioned by a proto_library rule; the collection of transitive descriptor sets is available through the [ProtoInfo].transitive_descriptor_sets Starlark provider. See documentation in ProtoInfo.java.

Recommended code organization:

• One proto_library rule per .proto file.
• A file named foo.proto will be in a rule named foo_proto, which is located in the same package.
• A [language]_proto_library that wraps a proto_library named foo_proto should be called foo_[language]_proto, and be located in the same package.

Arguments