1/* 2 * Copyright 2016 gRPC authors. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 * 16 */ 17 18// Package internal contains gRPC-internal code, to avoid polluting 19// the godoc of the top-level grpc package. It must not import any grpc 20// symbols to avoid circular dependencies. 21package internal 22 23import ( 24 "context" 25 "time" 26 27 "google.golang.org/grpc/connectivity" 28) 29 30var ( 31 // WithHealthCheckFunc is set by dialoptions.go 32 WithHealthCheckFunc interface{} // func (HealthChecker) DialOption 33 // HealthCheckFunc is used to provide client-side LB channel health checking 34 HealthCheckFunc HealthChecker 35 // BalancerUnregister is exported by package balancer to unregister a balancer. 36 BalancerUnregister func(name string) 37 // KeepaliveMinPingTime is the minimum ping interval. This must be 10s by 38 // default, but tests may wish to set it lower for convenience. 39 KeepaliveMinPingTime = 10 * time.Second 40 // NewRequestInfoContext creates a new context based on the argument context attaching 41 // the passed in RequestInfo to the new context. 42 NewRequestInfoContext interface{} // func(context.Context, credentials.RequestInfo) context.Context 43 // ParseServiceConfigForTesting is for creating a fake 44 // ClientConn for resolver testing only 45 ParseServiceConfigForTesting interface{} // func(string) *serviceconfig.ParseResult 46) 47 48// HealthChecker defines the signature of the client-side LB channel health checking function. 49// 50// The implementation is expected to create a health checking RPC stream by 51// calling newStream(), watch for the health status of serviceName, and report 52// it's health back by calling setConnectivityState(). 53// 54// The health checking protocol is defined at: 55// https://github.com/grpc/grpc/blob/master/doc/health-checking.md 56type HealthChecker func(ctx context.Context, newStream func(string) (interface{}, error), setConnectivityState func(connectivity.State, error), serviceName string) error 57 58const ( 59 // CredsBundleModeFallback switches GoogleDefaultCreds to fallback mode. 60 CredsBundleModeFallback = "fallback" 61 // CredsBundleModeBalancer switches GoogleDefaultCreds to grpclb balancer 62 // mode. 63 CredsBundleModeBalancer = "balancer" 64 // CredsBundleModeBackendFromBalancer switches GoogleDefaultCreds to mode 65 // that supports backend returned by grpclb balancer. 66 CredsBundleModeBackendFromBalancer = "backend-from-balancer" 67) 68