blob: 4bb4cdc6dfe1b1fbe7ae9cb129a6ebaae3e8533d [file] [log] [blame]
.. default-domain:: py
.. highlight:: py
.. _chapter-pw-protobuf-compiler:
--------------------
pw_protobuf_compiler
--------------------
The Protobuf compiler module provides build system integration and wrapper
scripts for generating source code for Protobuf definitions.
Generator support
=================
Protobuf code generation is currently supported for the following generators:
+-------------+----------------+-----------------------------------------------+
| Generator | Code | Notes |
+-------------+----------------+-----------------------------------------------+
| pw_protobuf | ``pwpb`` | Compiles using ``pw_protobuf``. |
+-------------+----------------+-----------------------------------------------+
| Go | ``go`` | Compiles using the standard Go protobuf |
| | | plugin with gRPC service support. |
+-------------+----------------+-----------------------------------------------+
| Nanopb | ``nanopb`` | Compiles using Nanopb. The build argument |
| | | ``dir_pw_third_party_nanopb`` must be set to |
| | | point to a local nanopb installation. |
+-------------+----------------+-----------------------------------------------+
| Nanopb RPC | ``nanopb_rpc`` | Compiles pw_rpc service code for a nanopb |
| | | server. Requires the nanopb generator to be |
| | | configured as well. |
+-------------+----------------+-----------------------------------------------+
The build variable ``pw_protobuf_GENERATORS`` tells the module the generators
for which it should compile code. It is defined as a list of generator codes.
GN template
===========
The ``pw_proto_library`` GN template is provided by the module.
It tells the build system to compile a set of source proto files to a library in
each chosen generator. A different target is created for each generator, with
the generator's code appended as a suffix to the template's target name.
For example, given the definitions:
.. code::
pw_protobuf_GENERATORS = [ "pwpb", "py" ]
pw_proto_library("test_protos") {
sources = [ "test.proto" ]
}
Two targets are created, named ``test_protos_pwpb`` and ``test_protos_py``,
containing the generated code from their respective generators.
**Arguments**
* ``sources``: List of ``.proto`` files.
* ``deps``: Other ``pw_proto_library`` targets that this one depends on.
**Example**
.. code::
import("$dir_pw_protobuf_compiler/proto.gni")
pw_proto_library("my_protos") {
sources = [
"foo.proto",
"bar.proto",
]
}
pw_proto_library("my_other_protos") {
sources = [
"baz.proto", # imports foo.proto
]
deps = [
":my_protos",
]
}
source_set("my_cc_code") {
sources = [
"foo.cc",
"bar.cc",
"baz.cc",
]
deps = [
":my_other_protos_cc",
]
}