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Source file src/github.com/google/s2a-go/internal/handshaker/service/service.go

Documentation: github.com/google/s2a-go/internal/handshaker/service

     1  /*
     2   *
     3   * Copyright 2021 Google LLC
     4   *
     5   * Licensed under the Apache License, Version 2.0 (the "License");
     6   * you may not use this file except in compliance with the License.
     7   * You may obtain a copy of the License at
     8   *
     9   *     https://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   *
    17   */
    18  
    19  // Package service is a utility for calling the S2A handshaker service.
    20  package service
    21  
    22  import (
    23  	"context"
    24  	"sync"
    25  
    26  	grpc "google.golang.org/grpc"
    27  	"google.golang.org/grpc/credentials"
    28  	"google.golang.org/grpc/credentials/insecure"
    29  )
    30  
    31  var (
    32  	// mu guards hsConnMap and hsDialer.
    33  	mu sync.Mutex
    34  	// hsConnMap represents a mapping from an S2A handshaker service address
    35  	// to a corresponding connection to an S2A handshaker service instance.
    36  	hsConnMap = make(map[string]*grpc.ClientConn)
    37  	// hsDialer will be reassigned in tests.
    38  	hsDialer = grpc.DialContext
    39  )
    40  
    41  // Dial dials the S2A handshaker service. If a connection has already been
    42  // established, this function returns it. Otherwise, a new connection is
    43  // created.
    44  func Dial(ctx context.Context, handshakerServiceAddress string, transportCreds credentials.TransportCredentials) (*grpc.ClientConn, error) {
    45  	mu.Lock()
    46  	defer mu.Unlock()
    47  
    48  	hsConn, ok := hsConnMap[handshakerServiceAddress]
    49  	if !ok {
    50  		// Create a new connection to the S2A handshaker service. Note that
    51  		// this connection stays open until the application is closed.
    52  		var grpcOpts []grpc.DialOption
    53  		if transportCreds != nil {
    54  			grpcOpts = append(grpcOpts, grpc.WithTransportCredentials(transportCreds))
    55  		} else {
    56  			grpcOpts = append(grpcOpts, grpc.WithTransportCredentials(insecure.NewCredentials()))
    57  		}
    58  		var err error
    59  		hsConn, err = hsDialer(ctx, handshakerServiceAddress, grpcOpts...)
    60  		if err != nil {
    61  			return nil, err
    62  		}
    63  		hsConnMap[handshakerServiceAddress] = hsConn
    64  	}
    65  	return hsConn, nil
    66  }
    67  

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