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import os
import sys
from typing import List, Any, Collection, Iterator, NamedTuple, cast
from typing import Dict, Tuple, Optional, Deque
from contextlib import contextmanager
from collections import deque
from google.protobuf.descriptor_pb2 import FileDescriptorProto, DescriptorProto
from google.protobuf.compiler.plugin_pb2 import CodeGeneratorRequest
from google.protobuf.compiler.plugin_pb2 import CodeGeneratorResponse
from .. import const
from .. import client
from .. import server
_CARDINALITY = {
(False, False): const.Cardinality.UNARY_UNARY,
(True, False): const.Cardinality.STREAM_UNARY,
(False, True): const.Cardinality.UNARY_STREAM,
(True, True): const.Cardinality.STREAM_STREAM,
}
class Method(NamedTuple):
name: str
cardinality: const.Cardinality
request_type: str
reply_type: str
class Service(NamedTuple):
name: str
methods: List[Method]
class Buffer:
def __init__(self) -> None:
self._lines: List[str] = []
self._indent = 0
def add(self, string: str, *args: Any, **kwargs: Any) -> None:
line = ' ' * self._indent * 4 + string.format(*args, **kwargs)
self._lines.append(line.rstrip(' '))
@contextmanager
def indent(self) -> Iterator[None]:
self._indent += 1
try:
yield
finally:
self._indent -= 1
def content(self) -> str:
return '\n'.join(self._lines) + '\n'
def render(
proto_file: str,
package: str,
imports: Collection[str],
services: Collection[Service],
) -> str:
buf = Buffer()
buf.add('# Generated by the Protocol Buffers compiler. DO NOT EDIT!')
buf.add('# source: {}', proto_file)
buf.add('# plugin: {}', __name__)
if not services:
return buf.content()
buf.add('import abc')
buf.add('import typing')
buf.add('')
buf.add('import {}', const.__name__)
buf.add('import {}', client.__name__)
buf.add('if typing.TYPE_CHECKING:')
with buf.indent():
buf.add('import {}', server.__name__)
buf.add('')
for mod in imports:
buf.add('import {}', mod)
for service in services:
if package:
service_name = '{}.{}'.format(package, service.name)
else:
service_name = service.name
buf.add('')
buf.add('')
buf.add('class {}Base(abc.ABC):', service.name)
with buf.indent():
for (name, _, request_type, reply_type) in service.methods:
buf.add('')
buf.add('@abc.abstractmethod')
buf.add("async def {}(self, stream: '{}.{}[{}, {}]') -> None:",
name, server.__name__, server.Stream.__name__,
request_type, reply_type)
with buf.indent():
buf.add('pass')
buf.add('')
buf.add('def __mapping__(self) -> typing.Dict[str, {}.{}]:',
const.__name__,
const.Handler.__name__)
with buf.indent():
buf.add('return {{')
with buf.indent():
for method in service.methods:
name, cardinality, request_type, reply_type = method
full_name = '/{}/{}'.format(service_name, name)
buf.add("'{}': {}.{}(", full_name, const.__name__,
const.Handler.__name__)
with buf.indent():
buf.add('self.{},', name)
buf.add('{}.{}.{},', const.__name__,
const.Cardinality.__name__,
cardinality.name)
buf.add('{},', request_type)
buf.add('{},', reply_type)
buf.add('),')
buf.add('}}')
buf.add('')
buf.add('')
buf.add('class {}Stub:', service.name)
with buf.indent():
buf.add('')
buf.add('def __init__(self, channel: {}.{}) -> None:'
.format(client.__name__, client.Channel.__name__))
with buf.indent():
if len(service.methods) == 0:
buf.add('pass')
for method in service.methods:
name, cardinality, request_type, reply_type = method
full_name = '/{}/{}'.format(service_name, name)
method_cls: type
if cardinality is const.Cardinality.UNARY_UNARY:
method_cls = client.UnaryUnaryMethod
elif cardinality is const.Cardinality.UNARY_STREAM:
method_cls = client.UnaryStreamMethod
elif cardinality is const.Cardinality.STREAM_UNARY:
method_cls = client.StreamUnaryMethod
elif cardinality is const.Cardinality.STREAM_STREAM:
method_cls = client.StreamStreamMethod
else:
raise TypeError(cardinality)
method_cls = cast(type, method_cls) # FIXME: redundant
buf.add('self.{} = {}.{}('.format(name, client.__name__,
method_cls.__name__))
with buf.indent():
buf.add('channel,')
buf.add('{!r},'.format(full_name))
buf.add('{},', request_type)
buf.add('{},', reply_type)
buf.add(')')
return buf.content()
def _get_proto(request: CodeGeneratorRequest, name: str) -> FileDescriptorProto:
return next(f for f in request.proto_file if f.name == name)
def _strip_proto(proto_file_path: str) -> str:
for suffix in [".protodevel", ".proto"]:
if proto_file_path.endswith(suffix):
return proto_file_path[: -len(suffix)]
return proto_file_path
def _base_module_name(proto_file_path: str) -> str:
basename = _strip_proto(proto_file_path)
return basename.replace("-", "_").replace("/", ".")
def _proto2pb2_module_name(proto_file_path: str) -> str:
return _base_module_name(proto_file_path) + "_pb2"
def _proto2grpc_module_name(proto_file_path: str) -> str:
return _base_module_name(proto_file_path) + "_grpc"
def _type_names(
proto_file: FileDescriptorProto,
message_type: DescriptorProto,
parents: Optional[Deque[str]] = None,
) -> Iterator[Tuple[str, str]]:
if parents is None:
parents = deque()
proto_name_parts = ['']
if proto_file.package:
proto_name_parts.append(proto_file.package)
proto_name_parts.extend(parents)
proto_name_parts.append(message_type.name)
py_name_parts = [_proto2pb2_module_name(proto_file.name)]
py_name_parts.extend(parents)
py_name_parts.append(message_type.name)
yield '.'.join(proto_name_parts), '.'.join(py_name_parts)
parents.append(message_type.name)
for nested in message_type.nested_type:
yield from _type_names(proto_file, nested, parents=parents)
parents.pop()
def main() -> None:
with os.fdopen(sys.stdin.fileno(), 'rb') as inp:
request = CodeGeneratorRequest.FromString(inp.read())
types_map: Dict[str, str] = {}
for pf in request.proto_file:
for mt in pf.message_type:
types_map.update(_type_names(pf, mt))
response = CodeGeneratorResponse()
# See https://github.com/protocolbuffers/protobuf/blob/v3.12.0/docs/implementing_proto3_presence.md # noqa
if hasattr(CodeGeneratorResponse, 'Feature'):
response.supported_features = (
CodeGeneratorResponse.FEATURE_PROTO3_OPTIONAL
)
for file_to_generate in request.file_to_generate:
proto_file = _get_proto(request, file_to_generate)
imports = [_proto2pb2_module_name(dep)
for dep in list(proto_file.dependency) + [file_to_generate]]
services = []
for service in proto_file.service:
methods = []
for method in service.method:
cardinality = _CARDINALITY[(method.client_streaming,
method.server_streaming)]
methods.append(Method(
name=method.name,
cardinality=cardinality,
request_type=types_map[method.input_type],
reply_type=types_map[method.output_type],
))
services.append(Service(name=service.name,
methods=methods))
file = response.file.add()
module_name = _proto2grpc_module_name(file_to_generate)
file.name = module_name.replace(".", "/") + ".py"
file.content = render(
proto_file=proto_file.name,
package=proto_file.package,
imports=imports,
services=services,
)
with os.fdopen(sys.stdout.fileno(), 'wb') as out:
out.write(response.SerializeToString())
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