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