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	"google.golang.org/grpc/serviceconfig"
29)
30
31var (
32	// WithHealthCheckFunc is set by dialoptions.go
33	WithHealthCheckFunc interface{} // func (HealthChecker) DialOption
34	// HealthCheckFunc is used to provide client-side LB channel health checking
35	HealthCheckFunc HealthChecker
36	// BalancerUnregister is exported by package balancer to unregister a balancer.
37	BalancerUnregister func(name string)
38	// KeepaliveMinPingTime is the minimum ping interval.  This must be 10s by
39	// default, but tests may wish to set it lower for convenience.
40	KeepaliveMinPingTime = 10 * time.Second
41	// ParseServiceConfigForTesting is for creating a fake
42	// ClientConn for resolver testing only
43	ParseServiceConfigForTesting interface{} // func(string) *serviceconfig.ParseResult
44	// EqualServiceConfigForTesting is for testing service config generation and
45	// parsing. Both a and b should be returned by ParseServiceConfigForTesting.
46	// This function compares the config without rawJSON stripped, in case the
47	// there's difference in white space.
48	EqualServiceConfigForTesting func(a, b serviceconfig.Config) bool
49	// GetCertificateProviderBuilder returns the registered builder for the
50	// given name. This is set by package certprovider for use from xDS
51	// bootstrap code while parsing certificate provider configs in the
52	// bootstrap file.
53	GetCertificateProviderBuilder interface{} // func(string) certprovider.Builder
54	// GetXDSHandshakeInfoForTesting returns a pointer to the xds.HandshakeInfo
55	// stored in the passed in attributes. This is set by
56	// credentials/xds/xds.go.
57	GetXDSHandshakeInfoForTesting interface{} // func (*attributes.Attributes) *xds.HandshakeInfo
58	// GetServerCredentials returns the transport credentials configured on a
59	// gRPC server. An xDS-enabled server needs to know what type of credentials
60	// is configured on the underlying gRPC server. This is set by server.go.
61	GetServerCredentials interface{} // func (*grpc.Server) credentials.TransportCredentials
62	// DrainServerTransports initiates a graceful close of existing connections
63	// on a gRPC server accepted on the provided listener address. An
64	// xDS-enabled server invokes this method on a grpc.Server when a particular
65	// listener moves to "not-serving" mode.
66	DrainServerTransports interface{} // func(*grpc.Server, string)
67)
68
69// HealthChecker defines the signature of the client-side LB channel health checking function.
70//
71// The implementation is expected to create a health checking RPC stream by
72// calling newStream(), watch for the health status of serviceName, and report
73// it's health back by calling setConnectivityState().
74//
75// The health checking protocol is defined at:
76// https://github.com/grpc/grpc/blob/master/doc/health-checking.md
77type HealthChecker func(ctx context.Context, newStream func(string) (interface{}, error), setConnectivityState func(connectivity.State, error), serviceName string) error
78
79const (
80	// CredsBundleModeFallback switches GoogleDefaultCreds to fallback mode.
81	CredsBundleModeFallback = "fallback"
82	// CredsBundleModeBalancer switches GoogleDefaultCreds to grpclb balancer
83	// mode.
84	CredsBundleModeBalancer = "balancer"
85	// CredsBundleModeBackendFromBalancer switches GoogleDefaultCreds to mode
86	// that supports backend returned by grpclb balancer.
87	CredsBundleModeBackendFromBalancer = "backend-from-balancer"
88)
89