Use gRPC to transfer database data immediately after table changes

Question content

I am making a task list using go, grpc and postgres.

How to automatically stream data when calling postitem to insert new data? Do I need to subscribe to postgres or can this be done without a subscribe or publish subscribe?

//protobuf architecture

syntax = "proto3";

package tasklist;

import "google/protobuf/empty.proto";

service todolist {
  rpc gettasks(google.protobuf.empty) returns (stream gettasksresponse) {}
  rpc postitem(postitemrequest) returns (posttaskrequest) {}
}


message task {
  int64 id = 1;
  string name = 2;
}

message gettasksresponse {
  task task = 1;
}

message posttaskrequest {
  task task = 1;
}

message postitemresponse {
  bool result = 1;
}

// postgres table structure

create table task (
  id integer not null primary key,
  name varchar(10) not null
);

// continue

func (s *server) GetTasks(_ *empty.Empty, stream pb.TaskList_GetTasksServer) error {
    // How can I steam data as soon as `PostTask` is called to update db? <- <-
    for _, r := range s.requests {
        // stream data
    }
}

func (s *server) PostTask(ctx context.Context, r *pb.PostTaskRequest) (*pb.PostTaskResponse, error) {
    // update Postgres here
    return &pb.PostItemResponse{Result: true}, nil
}

Correct answer

I guess s.requests is similar to chan task. So after successfully // update postgres here you can send your request in chan.

func (s *server) PostTask(ctx context.Context, r *pb.PostTaskRequest) (*pb.PostTaskResponse, error) {
    postTask := toDomain(r)
    err := s.service.UpdateTask(ctx, postTask)
    if err != nil {
        return nil, status.Error(codes.Internal, err.Error())
    }
    s.requests <- postTask
    return &pb.PostItemResponse{Result: true}, nil
}

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