feat: demonstrate python grpc

Ported from https://github.com/chrisirhc/precompiled-grpc-in-bazel-python

Author: alexeagle

examples/MODULE.bazel

@@ -7,6 +7,8 @@ bazel_dep(name = "platforms", version = "0.0.11")
 bazel_dep(name = "protobuf", version = "29.3")
 bazel_dep(name = "rules_java", version = "8.6.3")
 bazel_dep(name = "rules_proto", version = "7.1.0")
+bazel_dep(name = "rules_proto_grpc", version = "5.0.1")
+bazel_dep(name = "rules_proto_grpc_python", version = "5.0.1")
 bazel_dep(name = "rules_python", version = "1.2.0-rc0")
 bazel_dep(name = "rules_rust", version = "0.59.1")
 bazel_dep(name = "rules_rust_prost", version = "0.59.1")

examples/proto/BUILD.bazel

@@ -3,6 +3,7 @@ load("@rules_go//proto:def.bzl", "go_proto_library")
 load("@rules_proto//proto:defs.bzl", "proto_library")
 load("@rules_rust_prost//:defs.bzl", "rust_prost_library")
 load("@protobuf//bazel:py_proto_library.bzl", "py_proto_library")
+load("//python:python_grpc_compile.bzl", "python_grpc_compile")
 
 package(default_visibility = ["//visibility:public"])
 
@@ -17,6 +18,10 @@ py_proto_library(
     deps = [":greeter_proto"],
 )
 
+python_grpc_compile(
+    name = "greeter_py_grpc",
+    protos = [":greeter_proto"],
+)
 # Broken by https://github.com/protocolbuffers/protobuf/pull/19679
 # which causes building C++ code from source.
 # TODO: re-enable once protobuf honors the toolchain

examples/python/BUILD

@@ -1,7 +0,0 @@
-load("@rules_python//python:defs.bzl", "py_test")
-
-py_test(
-    name = "message_test",
-    srcs = ["message_test.py"],
-    deps = ["//proto:greeter_py_proto"],
-)

examples/python/message_test.py

@@ -0,0 +1,30 @@
+"""
+Generated definition of python_grpc_compile.
+Modified from https://github.com/rules-proto-grpc/rules_proto_grpc/blob/d17b5b16c8b12143c6f1b78dabd6bbc228e89b58/modules/python/python_grpc_compile.bzl
+"""
+
+load(
+    "@rules_proto_grpc//:defs.bzl",
+    "ProtoPluginInfo",
+    "proto_compile_attrs",
+    "proto_compile_impl",
+    "proto_compile_toolchains",
+)
+
+# Create compile rule
+python_grpc_compile = rule(
+    implementation = proto_compile_impl,
+    attrs = dict(
+        proto_compile_attrs,
+        _plugins = attr.label_list(
+            providers = [ProtoPluginInfo],
+            default = [
+                Label("//tools/toolchains:proto_plugin"),
+                Label("//tools/toolchains:grpc_plugin"),
+            ],
+            cfg = "exec",
+            doc = "List of protoc plugins to apply",
+        ),
+    ),
+    toolchains = proto_compile_toolchains,
+)

examples/python/python_grpc_compile.bzl

@@ -0,0 +1,11 @@
+load("@aspect_rules_py//py:defs.bzl", "py_binary")
+
+py_binary(
+    name = "server",
+    srcs = ["__main__.py"],
+    main = "__main__.py",
+    deps = [
+        "//proto:greeter_py_grpc",
+        "@pypi//grpcio",
+    ],
+)

examples/python/server/BUILD.bazel

@@ -0,0 +1,22 @@
+from concurrent import futures
+import logging
+import math
+import time
+
+import grpc
+from proto import greeter_pb2
+
+class Greeter(greeter_pb2.GreeterStub):
+    def SayHello(self, request, context):
+        return greeter_pb2.HelloReply(message=f'Hello {request.name}')
+
+def serve():
+    server = grpc.server(futures.ThreadPoolExecutor(max_workers=10))
+    greeter_pb2.add_Greeter_to_server(Greeter(), server)
+    server.add_insecure_port("[::1]:5042")
+    server.start()
+    server.wait_for_termination()
+
+if __name__ == "__main__":
+    logging.basicConfig()
+    serve()

examples/python/server/__main__.py

@@ -0,0 +1,11 @@
+load("@rules_python//python:defs.bzl", "py_binary")
+
+py_binary(
+    name = "protoc",
+    srcs = ["__main__.py"],
+    main = "__main__.py",
+    visibility = ["//visibility:public"],
+    deps = [
+        "@pypi//grpcio_tools",
+    ],
+)

examples/tools/grpcio_tools/BUILD.bazel

@@ -0,0 +1,3 @@
+import runpy
+
+runpy.run_module('grpc_tools.protoc', run_name='__main__')

examples/tools/grpcio_tools/__main__.py

@@ -1 +1,3 @@
 protobuf==5.28.0
+grpcio
+grpcio-tools