blob: d05cb6edd1a69632afe5ab273988df35bebef923 [file] [log] [blame]
# Copyright (c) 2009-2021, Google LLC
# All rights reserved.
#
# Use of this source code is governed by a BSD-style
# license that can be found in the LICENSE file or at
# https://developers.google.com/open-source/licenses/bsd
"""An implementation of py_proto_library().
We have to implement this ourselves because there is currently no reasonable
py_proto_library() rule available for Bazel.
Our py_proto_library() is similar to how a real py_proto_library() should work.
But it hasn't been deeply tested or reviewed, and upb should not be in the
business of vending py_proto_library(), so we keep it private to upb.
"""
load("@bazel_skylib//lib:paths.bzl", "paths")
load("@rules_python//python:py_info.bzl", "PyInfo")
load("//bazel/common:proto_info.bzl", "ProtoInfo")
# Generic support code #########################################################
# begin:github_only
_is_google3 = False
# end:github_only
# begin:google_only
# _is_google3 = True
# end:google_only
def _get_real_short_path(file):
# For some reason, files from other archives have short paths that look like:
# ../com_google_protobuf/google/protobuf/descriptor.proto
short_path = file.short_path
if short_path.startswith("../"):
second_slash = short_path.index("/", 3)
short_path = short_path[second_slash + 1:]
# Sometimes it has another few prefixes like:
# _virtual_imports/any_proto/google/protobuf/any.proto
# benchmarks/_virtual_imports/100_msgs_proto/benchmarks/100_msgs.proto
# We want just google/protobuf/any.proto.
virtual_imports = "_virtual_imports/"
if virtual_imports in short_path:
short_path = short_path.split(virtual_imports)[1].split("/", 1)[1]
return short_path
def _get_real_root(ctx, file):
real_short_path = _get_real_short_path(file)
root = file.path[:-len(real_short_path) - 1]
if not _is_google3 and ctx.rule.attr.strip_import_prefix:
root = paths.join(root, ctx.rule.attr.strip_import_prefix[1:])
return root
def _generate_output_file(ctx, src, extension):
package = ctx.label.package
if not _is_google3:
strip_import_prefix = ctx.rule.attr.strip_import_prefix
if strip_import_prefix and strip_import_prefix != "/":
if not package.startswith(strip_import_prefix[1:]):
fail("%s does not begin with prefix %s" % (package, strip_import_prefix))
package = package[len(strip_import_prefix):]
real_short_path = _get_real_short_path(src)
real_short_path = paths.relativize(real_short_path, package)
output_filename = paths.replace_extension(real_short_path, extension)
ret = ctx.actions.declare_file(output_filename)
return ret
# py_proto_library() ###########################################################
def _py_proto_library_rule_impl(ctx):
# A real py_proto_library() should enforce this constraint.
# We don't bother for now, since it saves us some effort not to.
#
# if len(ctx.attr.deps) != 1:
# fail("only one deps dependency allowed.")
files = []
for dep in ctx.attr.deps:
files += dep[PyInfo].transitive_sources.to_list()
return [
DefaultInfo(files = depset(direct = files)),
]
def _py_proto_library_aspect_impl(target, ctx):
proto_info = target[ProtoInfo]
proto_sources = proto_info.direct_sources
srcs = [_generate_output_file(ctx, name, "_pb2.py") for name in proto_sources]
transitive_sets = proto_info.transitive_descriptor_sets.to_list()
ctx.actions.run(
inputs = depset(
direct = [proto_info.direct_descriptor_set],
transitive = [proto_info.transitive_descriptor_sets],
),
outputs = srcs,
executable = ctx.executable._protoc,
arguments = [
"--python_out=" + _get_real_root(ctx, srcs[0]),
"--descriptor_set_in=" + ctx.configuration.host_path_separator.join([f.path for f in transitive_sets]),
] +
[_get_real_short_path(file) for file in proto_sources],
progress_message = "Generating Python protos for :" + ctx.label.name,
)
outs_depset = depset(srcs)
return [
PyInfo(transitive_sources = outs_depset),
]
_py_proto_library_aspect = aspect(
attrs = {
"_protoc": attr.label(
executable = True,
cfg = "exec",
default = "//:protoc",
),
},
implementation = _py_proto_library_aspect_impl,
provides = [
PyInfo,
],
attr_aspects = ["deps"],
)
py_proto_library = rule(
implementation = _py_proto_library_rule_impl,
attrs = {
"deps": attr.label_list(
aspects = [_py_proto_library_aspect],
allow_rules = ["proto_library"],
providers = [ProtoInfo],
),
},
)