build: python proto generation in api_build_system.bzl. (#39)

WORKSPACE

@@ -6,7 +6,7 @@ new_git_repository(
     commit = "5c6df0cd18c6a429eab739fb711c27f6e1393366",
     remote = "https://github.com/googleapis/googleapis.git",
     build_file_content = """
-load("@protobuf//:protobuf.bzl", "cc_proto_library")
+load("@protobuf//:protobuf.bzl", "cc_proto_library", "py_proto_library")
 
 cc_proto_library(
     name = "http_api_protos",
@@ -19,6 +19,19 @@ cc_proto_library(
     visibility = ["//visibility:public"],
     deps = ["@protobuf//:cc_wkt_protos"],
 )
+
+py_proto_library(
+    name = "http_api_protos_py",
+    srcs = [
+        "google/api/annotations.proto",
+        "google/api/http.proto",
+    ],
+    include = ".",
+    default_runtime = "@protobuf//:protobuf_python",
+    protoc = "@protobuf//:protoc",
+    visibility = ["//visibility:public"],
+    deps = ["@protobuf//:protobuf_python"],
+)
     """,
 )
 
@@ -28,3 +41,15 @@ git_repository(
     commit = "455b61c6b0f39ac269b26969877dd3c6f3e32270",
     remote = "https://github.com/google/protobuf.git",
 )
+
+new_http_archive(
+    name = "six_archive",
+    build_file = "@protobuf//:six.BUILD",
+    sha256 = "105f8d68616f8248e24bf0e9372ef04d3cc10104f1980f54d57b2ce73a5ad56a",
+    url = "https://pypi.python.org/packages/source/s/six/six-1.10.0.tar.gz#md5=34eed507548117b2ab523ab14b2f8b55",
+)
+
+bind(
+    name = "six",
+    actual = "@six_archive//:six",
+)

bazel/api_build_system.bzl

@@ -1,4 +1,4 @@
-load("@protobuf//:protobuf.bzl", "cc_proto_library")
+load("@protobuf//:protobuf.bzl", "cc_proto_library", "py_proto_library")
 
 # TODO(htuch): has_services is currently ignored but will in future support
 # gRPC stub generation.
@@ -12,4 +12,17 @@ def api_proto_library(name, srcs = [], deps = [], has_services = 0):
             "@googleapis//:http_api_protos",
             "@protobuf//:cc_wkt_protos",
         ],
+        visibility = ["//visibility:public"],
+    )
+
+    py_proto_library(
+        name = name + "_py",
+        srcs = srcs,
+        default_runtime = "@protobuf//:protobuf_python",
+        protoc = "@protobuf//:protoc",
+        deps = [d + "_py" for d in deps] + [
+            "@googleapis//:http_api_protos_py",
+            "@protobuf//:protobuf_python",
+        ],
+        visibility = ["//visibility:public"],
     )