Build Protobuf and Thrift¶

proto_library¶

Build protobuf targets

proto_library(
    name = 'rpc_meta_info_proto',
    srcs = 'rpc_meta_info.proto',
    deps = ':rpc_option_proto',
)

deps are other proto_library which are imported. protobuf runtime library will be depended automatically, needn't to be specified explicitly.

proto_library support generate targets for multiple target languages.

When generate for C++ code, it generate a c++ library with corresponding header files. To include the generated header file of a proto file, you should include it with the full path from the root of the workspace, replace the proto suffix into pb.h. For example, the header file of //common/base/string_test.proto is "common/base/string_test.pb.h".

When a java targets depends on a proto_library, the java relatived code will be generated automatically, it is also similar to other target languages,such as python. so we only need one proto_library for multiple target languages.

If you want to generate code for specified languages unconditionly, you can use the target_languages argument:

proto_library(
    name = 'rpc_meta_info_proto',
    srcs = 'rpc_meta_info.proto',
    deps = ':rpc_option_proto',
    target_languages = ['java', 'python'],
)

The cpp target code is always generated.

If you want to generate some cpp code with other suffix names, you can use cpp_outs attributes. The default value is ['.pb']. For example, if you want to use grpc plugin to generate rpc_meta_info.pb.cc/h and rpc_meta_info.grpc.pb.cc/h, set cpp_outs = [".pb', '.grpc.pb']

Besides, use plugin_opts to pass some options to plugins, like plugin_opts={"plugin_name":["option1", "option2.."]},. Blade will pass --plugin_name_opt=option1 --plugin_name_opt=option2 to grpc plugin.

proto_library(
    name = 'rpc_meta_info_proto',
    srcs = 'rpc_meta_info.proto',
    deps = ':rpc_option_proto',
    target_languages = ['java', 'python'],
    plugins = ['grpc'],
    cpp_outs = ['.pb', '.grpc.pb'],
    plugin_opts = {
        'grpc': ["option1", "option2"],
    },
)

Import root: `strip_import_prefix`¶

By default a proto is imported and its generated header is referenced relative to the workspace root: a proto at //foo/bar/x.proto is imported as import "foo/bar/x.proto"; and generates "foo/bar/x.pb.h".

Some projects instead root their protos at a source subdirectory — their protos import "bar/x.proto"; and their C++ #include "bar/x.pb.h", where bar/ lives under e.g. src/. Set strip_import_prefix to that root (a path relative to the BUILD package) so Blade compiles with --proto_path=<package>/<prefix> and both the imports and the generated #includes resolve there instead of at the workspace root:

proto_library(
    name = 'options_proto',
    srcs = 'src/foo/bar/x.proto',   # imports "bar/y.proto"; code #includes "bar/x.pb.h"
    strip_import_prefix = 'src/foo', # -> proto compiles with --proto_path=src/foo
)

This is the analog of Bazel's proto_library(strip_import_prefix=...). It currently affects the generated C++ outputs.

thrift_library¶

Can be used to generate thrift C++ library deps is the other thrift_library which are imported. thrift runtime will be depended automatically, needn't to be specified explicitly. The generated result is a c++ linrary with with corresponding header files.

thrift_library(
    name = 'shared_thrift',
    srcs = 'shared.thrift',
)

thrift_library(
    name = 'tutorial_thrift',
    srcs = 'tutorial.thrift',
    deps = ':shared_thrift'
)

Similay to proto_library, to include generated header files, the full path is also required.

Build Protobuf and Thrift¶

proto_library¶

Import root: strip_import_prefix¶

thrift_library¶

Import root: `strip_import_prefix`¶