text: # -*- coding: utf-8 -*-
  
  # Copyright 2020 Google LLC
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  #
  
  from typing import Callable, Dict, Optional, Sequence, Tuple
  
  from google.api_core import grpc_helpers  # type: ignore
  from google.api_core import gapic_v1  # type: ignore
  from google import auth  # type: ignore
  from google.auth import credentials  # type: ignore
  from google.auth.transport.grpc import SslCredentials  # type: ignore
  
  
  import grpc  # type: ignore
  
  from google.cloud.trace_v2.types import trace
  from google.cloud.trace_v2.types import tracing
  from google.protobuf import empty_pb2 as empty  # type: ignore
  
  from .base import TraceServiceTransport, DEFAULT_CLIENT_INFO
  
  
  class TraceServiceGrpcTransport(TraceServiceTransport):
      """gRPC backend transport for TraceService.
  
      This file describes an API for collecting and viewing traces
      and spans within a trace.  A Trace is a collection of spans
      corresponding to a single operation or set of operations for an
      application. A span is an individual timed event which forms a
      node of the trace tree. A single trace may contain span(s) from
      multiple services.
  
      This class defines the same methods as the primary client, so the
      primary client can load the underlying transport implementation
      and call it.
  
      It sends protocol buffers over the wire using gRPC (which is built on
      top of HTTP/2); the ``grpcio`` package must be installed.
      """
  
      _stubs: Dict[str, Callable]
  
      def __init__(
          self,
          *,
          host: str = "cloudtrace.googleapis.com",
          credentials: credentials.Credentials = None,
          credentials_file: str = None,
          scopes: Sequence[str] = None,
          channel: grpc.Channel = None,
          api_mtls_endpoint: str = None,
          client_cert_source: Callable[[], Tuple[bytes, bytes]] = None,
          quota_project_id: Optional[str] = None,
          client_info: gapic_v1.client_info.ClientInfo = DEFAULT_CLIENT_INFO,
      ) -> None:
          """Instantiate the transport.
  
          Args:
              host (Optional[str]): The hostname to connect to.
              credentials (Optional[google.auth.credentials.Credentials]): The
                  authorization credentials to attach to requests. These
                  credentials identify the application to the service; if none
                  are specified, the client will attempt to ascertain the
                  credentials from the environment.
                  This argument is ignored if ``channel`` is provided.
              credentials_file (Optional[str]): A file with credentials that can
                  be loaded with :func:`google.auth.load_credentials_from_file`.
                  This argument is ignored if ``channel`` is provided.
              scopes (Optional(Sequence[str])): A list of scopes. This argument is
                  ignored if ``channel`` is provided.
              channel (Optional[grpc.Channel]): A ``Channel`` instance through
                  which to make calls.
              api_mtls_endpoint (Optional[str]): The mutual TLS endpoint. If
                  provided, it overrides the ``host`` argument and tries to create
                  a mutual TLS channel with client SSL credentials from
                  ``client_cert_source`` or applicatin default SSL credentials.
              client_cert_source (Optional[Callable[[], Tuple[bytes, bytes]]]): A
                  callback to provide client SSL certificate bytes and private key
                  bytes, both in PEM format. It is ignored if ``api_mtls_endpoint``
                  is None.
              quota_project_id (Optional[str]): An optional project to use for billing
                  and quota.
              client_info (google.api_core.gapic_v1.client_info.ClientInfo):	
                  The client info used to send a user-agent string along with	
                  API requests. If ``None``, then default info will be used.	
                  Generally, you only need to set this if you're developing	
                  your own client library.
  
          Raises:
            google.auth.exceptions.MutualTLSChannelError: If mutual TLS transport
                creation failed for any reason.
            google.api_core.exceptions.DuplicateCredentialArgs: If both ``credentials``
                and ``credentials_file`` are passed.
          """
          if channel:
              # Sanity check: Ensure that channel and credentials are not both
              # provided.
              credentials = False
  
              # If a channel was explicitly provided, set it.
              self._grpc_channel = channel
          elif api_mtls_endpoint:
              host = (
                  api_mtls_endpoint
                  if ":" in api_mtls_endpoint
                  else api_mtls_endpoint + ":443"
              )
  
              if credentials is None:
                  credentials, _ = auth.default(
                      scopes=self.AUTH_SCOPES, quota_project_id=quota_project_id
                  )
  
              # Create SSL credentials with client_cert_source or application
              # default SSL credentials.
              if client_cert_source:
                  cert, key = client_cert_source()
                  ssl_credentials = grpc.ssl_channel_credentials(
                      certificate_chain=cert, private_key=key
                  )
              else:
                  ssl_credentials = SslCredentials().ssl_credentials
  
              # create a new channel. The provided one is ignored.
              self._grpc_channel = type(self).create_channel(
                  host,
                  credentials=credentials,
                  credentials_file=credentials_file,
                  ssl_credentials=ssl_credentials,
                  scopes=scopes or self.AUTH_SCOPES,
                  quota_project_id=quota_project_id,
              )
  
          self._stubs = {}  # type: Dict[str, Callable]
  
          # Run the base constructor.
          super().__init__(
              host=host,
              credentials=credentials,
              credentials_file=credentials_file,
              scopes=scopes or self.AUTH_SCOPES,
              quota_project_id=quota_project_id,
              client_info=client_info,
          )
  
      @classmethod
      def create_channel(
          cls,
          host: str = "cloudtrace.googleapis.com",
          credentials: credentials.Credentials = None,
          credentials_file: str = None,
          scopes: Optional[Sequence[str]] = None,
          quota_project_id: Optional[str] = None,
          **kwargs,
      ) -> grpc.Channel:
          """Create and return a gRPC channel object.
          Args:
              address (Optionsl[str]): The host for the channel to use.
              credentials (Optional[~.Credentials]): The
                  authorization credentials to attach to requests. These
                  credentials identify this application to the service. If
                  none are specified, the client will attempt to ascertain
                  the credentials from the environment.
              credentials_file (Optional[str]): A file with credentials that can
                  be loaded with :func:`google.auth.load_credentials_from_file`.
                  This argument is mutually exclusive with credentials.
              scopes (Optional[Sequence[str]]): A optional list of scopes needed for this
                  service. These are only used when credentials are not specified and
                  are passed to :func:`google.auth.default`.
              quota_project_id (Optional[str]): An optional project to use for billing
                  and quota.
              kwargs (Optional[dict]): Keyword arguments, which are passed to the
                  channel creation.
          Returns:
              grpc.Channel: A gRPC channel object.
  
          Raises:
              google.api_core.exceptions.DuplicateCredentialArgs: If both ``credentials``
                and ``credentials_file`` are passed.
          """
          scopes = scopes or cls.AUTH_SCOPES
          return grpc_helpers.create_channel(
              host,
              credentials=credentials,
              credentials_file=credentials_file,
              scopes=scopes,
              quota_project_id=quota_project_id,
              **kwargs,
          )
  
      @property
      def grpc_channel(self) -> grpc.Channel:
          """Create the channel designed to connect to this service.
  
          This property caches on the instance; repeated calls return
          the same channel.
          """
          # Sanity check: Only create a new channel if we do not already
          # have one.
          if not hasattr(self, "_grpc_channel"):
              self._grpc_channel = self.create_channel(
                  self._host, credentials=self._credentials,
              )
  
          # Return the channel from cache.
          return self._grpc_channel
  
      @property
      def batch_write_spans(
          self,
      ) -> Callable[[tracing.BatchWriteSpansRequest], empty.Empty]:
          r"""Return a callable for the batch write spans method over gRPC.
  
          Sends new spans to new or existing traces. You cannot
          update existing spans.
  
          Returns:
              Callable[[~.BatchWriteSpansRequest],
                      ~.Empty]:
                  A function that, when called, will call the underlying RPC
                  on the server.
          """
          # Generate a "stub function" on-the-fly which will actually make
          # the request.
          # gRPC handles serialization and deserialization, so we just need
          # to pass in the functions for each.
          if "batch_write_spans" not in self._stubs:
              self._stubs["batch_write_spans"] = self.grpc_channel.unary_unary(
                  "/google.devtools.cloudtrace.v2.TraceService/BatchWriteSpans",
                  request_serializer=tracing.BatchWriteSpansRequest.serialize,
                  response_deserializer=empty.Empty.FromString,
              )
          return self._stubs["batch_write_spans"]
  
      @property
      def create_span(self) -> Callable[[trace.Span], trace.Span]:
          r"""Return a callable for the create span method over gRPC.
  
          Creates a new span.
  
          Returns:
              Callable[[~.Span],
                      ~.Span]:
                  A function that, when called, will call the underlying RPC
                  on the server.
          """
          # Generate a "stub function" on-the-fly which will actually make
          # the request.
          # gRPC handles serialization and deserialization, so we just need
          # to pass in the functions for each.
          if "create_span" not in self._stubs:
              self._stubs["create_span"] = self.grpc_channel.unary_unary(
                  "/google.devtools.cloudtrace.v2.TraceService/CreateSpan",
                  request_serializer=trace.Span.serialize,
                  response_deserializer=trace.Span.deserialize,
              )
          return self._stubs["create_span"]
  
  
  __all__ = ("TraceServiceGrpcTransport",)
  