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/*
*
* Copyright 2021 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
*
* https://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.
*
*/
// Package service is a utility for calling the S2A handshaker service.
package service
import (
"context"
"sync"
grpc "google.golang.org/grpc"
"google.golang.org/grpc/credentials"
"google.golang.org/grpc/credentials/insecure"
)
var (
// mu guards hsConnMap and hsDialer.
mu sync.Mutex
// hsConnMap represents a mapping from an S2A handshaker service address
// to a corresponding connection to an S2A handshaker service instance.
hsConnMap = make(map[string]*grpc.ClientConn)
// hsDialer will be reassigned in tests.
hsDialer = grpc.DialContext
)
// Dial dials the S2A handshaker service. If a connection has already been
// established, this function returns it. Otherwise, a new connection is
// created.
func Dial(ctx context.Context, handshakerServiceAddress string, transportCreds credentials.TransportCredentials) (*grpc.ClientConn, error) {
mu.Lock()
defer mu.Unlock()
hsConn, ok := hsConnMap[handshakerServiceAddress]
if !ok {
// Create a new connection to the S2A handshaker service. Note that
// this connection stays open until the application is closed.
var grpcOpts []grpc.DialOption
if transportCreds != nil {
grpcOpts = append(grpcOpts, grpc.WithTransportCredentials(transportCreds))
} else {
grpcOpts = append(grpcOpts, grpc.WithTransportCredentials(insecure.NewCredentials()))
}
var err error
hsConn, err = hsDialer(ctx, handshakerServiceAddress, grpcOpts...)
if err != nil {
return nil, err
}
hsConnMap[handshakerServiceAddress] = hsConn
}
return hsConn, nil
}
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