Interface

Registry has two interface, the Registrar is for services’ register and deregister, the Discovery is for fetching the list of services.

type Registrar interface {
    // register the service
    Register(ctx context.Context, service *ServiceInstance) error
    // deregister the service
    Deregister(ctx context.Context, service *ServiceInstance) error
}

type Discovery interface {
    // fetch the service list of serviceName
    Fetch(ctx context.Context, serviceName string) ([]*ServiceInstance, error)
    // subscribe to a list of serviceName
    Watch(ctx context.Context, serviceName string) (Watcher, error)
}

Implementations: consul etcd k8s

Usage

Register a Service

Create a Registrar(e.g. consul) and inject it to Kratos applications. Then the framework will do register and deregister automatically.

import consul "github.com/go-kratos/consul/registry"
import    "github.com/hashicorp/consul/api"
cli, err := api.NewClient(api.DefaultConfig())
if err != nil {
    panic(err)
}
reg := consul.New(cli)
app := kratos.New(
    kratos.Name(Name),
    kratos.Version(Version),
    kratos.Metadata(map[string]string{}),
    kratos.Logger(logger),
    kratos.Server(
        hs,
        gs,
    ),
    kratos.Registrar(reg),
)

Service Discovery (gRPC)

Create a Registrar(e.g. consul), create an Endpoint with url format as <schema>://[namespace]/<service-name>, then use grc.WithDiscovery and grpc.WithEndpoint as the options of the Dial method to get the gRPC connection.

import "github.com/go-kratos/kratos/transport/http"
import "github.com/go-kratos/kratos/v2/transport/grpc"
cli, err := api.NewClient(api.DefaultConfig())
if err != nil {
    panic(err)
}
dis := consul.New(cli)
endpoint := "discovery://default/provider"
conn, err := grpc.Dial(context.Background(), grpc.WithEndpoint(endpoint), grpc.WithDiscovery(dis))
if err != nil {
    panic(err)
}