go-sdk/example/serving/main.go

93 lines
2.8 KiB
Go

package main
import (
"context"
"fmt"
"log"
"net"
"github.com/golang/protobuf/ptypes/any"
"github.com/golang/protobuf/ptypes/empty"
pbc "github.com/dapr/go-sdk/dapr/proto/common/v1"
pb "github.com/dapr/go-sdk/dapr/proto/daprclient/v1"
"google.golang.org/grpc"
)
// server is our user app
type server struct {
}
func main() {
// create listener
lis, err := net.Listen("tcp", ":4000")
if err != nil {
log.Fatalf("failed to listen: %v", err)
}
// create gRPC server
s := grpc.NewServer()
pb.RegisterDaprClientServer(s, &server{})
fmt.Println("client starting...")
// and start...
if err := s.Serve(lis); err != nil {
log.Fatalf("failed to serve: %v", err)
}
}
// Sample method to invoke
func (s *server) MyMethod() string {
return "pong"
}
// This method gets invoked when a remote service has called the app through dapr
// The payload carries a Method to identify the method, a set of metadata properties and an optional payload
func (s *server) OnInvoke(ctx context.Context, in *pbc.InvokeRequest) (*pbc.InvokeResponse, error) {
var response string
fmt.Println(fmt.Sprintf("got invoked with: %s", string(in.Data.Value)))
switch in.Method {
case "MyMethod":
response = s.MyMethod()
}
return &pbc.InvokeResponse{
ContentType: "text/plain; charset=UTF-8",
Data: &any.Any{Value: []byte(response)},
}, nil
}
// GetTopicSubscriptions will call this method to get the list of topics the app wants to subscribe to.
// In this example, we are telling dapr. To subscribe to a topic named example-topic
func (s *server) GetTopicSubscriptions(ctx context.Context, in *empty.Empty) (*pb.GetTopicSubscriptionsEnvelope, error) {
return &pb.GetTopicSubscriptionsEnvelope{
Topics: []string{"example-topic"},
}, nil
}
// GetBindingsSubscriptions will call this method to get the list of bindings the app will get invoked by. In this example, we are telling dapr
// To invoke our app with a binding named storage
func (s *server) GetBindingsSubscriptions(ctx context.Context, in *empty.Empty) (*pb.GetBindingsSubscriptionsEnvelope, error) {
return &pb.GetBindingsSubscriptionsEnvelope{
Bindings: []string{"example-storage"},
}, nil
}
// OnBindingEvent method gets invoked every time a new event is fired from a registered binding.
// The message carries the binding name, a payload and optional metadata
func (s *server) OnBindingEvent(ctx context.Context, in *pb.BindingEventEnvelope) (*pb.BindingResponseEnvelope, error) {
fmt.Println("Invoked from binding")
return &pb.BindingResponseEnvelope{}, nil
}
// OnTopicEvent method is fired whenever a message has been published to a topic that has been subscribed.
// dapr sends published messages in a CloudEvents 0.3 envelope.
func (s *server) OnTopicEvent(ctx context.Context, in *pb.CloudEventEnvelope) (*empty.Empty, error) {
fmt.Println("Topic message arrived")
return &empty.Empty{}, nil
}