grpcgcp

Overview ¶

Package grpcgcp provides grpc supports for Google Cloud APIs. For now it provides connection management with affinity support.

Note: "channel" is analagous to "connection" in our context.

Usage:

1. First, initialize the api configuration. There are two ways:

1a. Create a json file defining the configuration and read it.

	// Create some_api_config.json
	{
		"channelPool": {
			"maxSize": 4,
			"maxConcurrentStreamsLowWatermark": 50
		},
		"method": [
			{
				"name": [ "/some.api.v1/Method1" ],
				"affinity": {
					"command": "BIND",
					"affinityKey": "key1"
				}
			},
			{
				"name": [ "/some.api.v1/Method2" ],
				"affinity": {
					"command": "BOUND",
					"affinityKey": "key2"
				}
			},
			{
				"name": [ "/some.api.v1/Method3" ],
				"affinity": {
					"command": "UNBIND",
					"affinityKey": "key3"
				}
			}
		]
	}

	jsonFile, err := ioutil.ReadFile("some_api_config.json")
	if err != nil {
		t.Fatalf("Failed to read config file: %v", err)
	}
	jsonCfg := string(jsonFile)

1b. Create apiConfig directly and convert it to json.

	// import (
	// 	configpb "github.com/GoogleCloudPlatform/grpc-gcp-go/grpcgcp/grpc_gcp"
	// )

	apiConfig := &configpb.ApiConfig{
		ChannelPool: &configpb.ChannelPoolConfig{
			MaxSize:                          4,
			MaxConcurrentStreamsLowWatermark: 50,
		},
		Method: []*configpb.MethodConfig{
			&configpb.MethodConfig{
				Name: []string{"/some.api.v1/Method1"},
				Affinity: &configpb.AffinityConfig{
					Command:     configpb.AffinityConfig_BIND,
					AffinityKey: "key1",
				},
			},
			&configpb.MethodConfig{
				Name: []string{"/some.api.v1/Method2"},
				Affinity: &configpb.AffinityConfig{
					Command:     configpb.AffinityConfig_BOUND,
					AffinityKey: "key2",
				},
			},
			&configpb.MethodConfig{
				Name: []string{"/some.api.v1/Method3"},
				Affinity: &configpb.AffinityConfig{
					Command:     configpb.AffinityConfig_UNBIND,
					AffinityKey: "key3",
				},
			},
		},
	}

	c, err := protojson.Marshal(apiConfig)
	if err != nil {
		t.Fatalf("cannot json encode config: %v", err)
	}
	jsonCfg := string(c)

2. Make ClientConn with specific DialOptions to enable grpc_gcp load balancer with provided configuration. And specify gRPC-GCP interceptors.

conn, err := grpc.Dial(
	target,
	// Register and specify the grpc-gcp load balancer.
	grpc.WithDisableServiceConfig(),
	grpc.WithDefaultServiceConfig(
		fmt.Sprintf(
			`{"loadBalancingConfig": [{"%s":%s}]}`,
			grpcgcp.Name,
			jsonCfg,
		),
	),
	// Set grpcgcp interceptors.
	grpc.WithUnaryInterceptor(grpcgcp.GCPUnaryClientInterceptor),
	grpc.WithStreamInterceptor(grpcgcp.GCPStreamClientInterceptor),
)