README
¶
Dapr HTTP Service SDK for Go
Start by importing Dapr Go service/http package:
daprd "github.com/dapr/go-sdk/service/http"
Creating and Starting Service
To create an HTTP Dapr service, first, create a Dapr callback instance with a specific address:
s := daprd.NewService(":8080")
Or with address and an existing http.ServeMux in case you want to combine existing server implementations:
mux := http.NewServeMux()
mux.HandleFunc("/", myOtherHandler)
s := daprd.NewServiceWithMux(":8080", mux)
Once you create a service instance, you can "attach" to that service any number of event, binding, and service invocation logic handlers as shown below. Onces the logic is defined, you are ready to start the service:
if err := s.Start(); err != nil && err != http.ErrServerClosed {
log.Fatalf("error: %v", err)
}
Event Handling
To handle events from specific topic you need to add at least one topic event handler before starting the service:
sub := &common.Subscription{
PubsubName: "messages",
Topic: "topic1",
Route: "/events",
}
err := s.AddTopicEventHandler(sub, eventHandler)
if err != nil {
log.Fatalf("error adding topic subscription: %v", err)
}
The handler method itself can be any method with the expected signature:
func eventHandler(ctx context.Context, e *common.TopicEvent) (retry bool, err error) {
log.Printf("event - PubsubName:%s, Topic:%s, ID:%s, Data: %v", e.PubsubName, e.Topic, e.ID, e.Data)
// do something with the event
return true, nil
}
Service Invocation Handler
To handle service invocations you will need to add at least one service invocation handler before starting the service:
if err := s.AddServiceInvocationHandler("/echo", echoHandler); err != nil {
log.Fatalf("error adding invocation handler: %v", err)
}
The handler method itself can be any method with the expected signature:
func echoHandler(ctx context.Context, in *common.InvocationEvent) (out *common.Content, err error) {
log.Printf("echo - ContentType:%s, Verb:%s, QueryString:%s, %+v", in.ContentType, in.Verb, in.QueryString, string(in.Data))
// do something with the invocation here
out = &common.Content{
Data: in.Data,
ContentType: in.ContentType,
DataTypeURL: in.DataTypeURL,
}
return
}
Binding Invocation Handler
To handle binding invocations you will need to add at least one binding invocation handler before starting the service:
if err := s.AddBindingInvocationHandler("/run", runHandler); err != nil {
log.Fatalf("error adding binding handler: %v", err)
}
The handler method itself can be any method with the expected signature:
func runHandler(ctx context.Context, in *common.BindingEvent) (out []byte, err error) {
log.Printf("binding - Data:%v, Meta:%v", in.Data, in.Metadata)
// do something with the invocation here
return nil, nil
}
Templates
To accelerate your HTTP Dapr app development in Go even further you can use one of the GitHub templates integrating the HTTP Dapr callback package:
- Dapr HTTP Event Subscriber in Go - Template project to jump start your Dapr event subscriber service with HTTP development
- Dapr HTTP cron Handler in Go - Template project to jump start your Dapr service development for scheduled workloads
Contributing to Dapr Go client
See the Contribution Guide to get started with building and developing.
Documentation
¶
Index ¶
- Constants
- func NewService(address string) common.Service
- func NewServiceWithMux(address string, mux *chi.Mux) common.Service
- type Server
- func (s *Server) AddBindingInvocationHandler(route string, fn common.BindingInvocationHandler) error
- func (s *Server) AddHealthCheckHandler(route string, fn common.HealthCheckHandler) error
- func (s *Server) AddServiceInvocationHandler(route string, fn common.ServiceInvocationHandler) error
- func (s *Server) AddTopicEventHandler(sub *common.Subscription, fn common.TopicEventHandler) error
- func (s *Server) GracefulStop() error
- func (s *Server) RegisterActorImplFactory(f actor.Factory, opts ...config.Option)deprecated
- func (s *Server) RegisterActorImplFactoryContext(f actor.FactoryContext, opts ...config.Option)
- func (s *Server) Start() error
- func (s *Server) Stop() error
Constants ¶
const ( // PubSubHandlerSuccessStatusCode is the successful ack code for pubsub event appcallback response. PubSubHandlerSuccessStatusCode int = http.StatusOK // PubSubHandlerRetryStatusCode is the error response code (nack) pubsub event appcallback response. PubSubHandlerRetryStatusCode int = http.StatusInternalServerError // PubSubHandlerDropStatusCode is the pubsub event appcallback response code indicating that Dapr should drop that message. PubSubHandlerDropStatusCode int = http.StatusSeeOther )
Variables ¶
This section is empty.
Functions ¶
func NewServiceWithMux ¶
NewServiceWithMux creates new Service with existing http mux.
Types ¶
type Server ¶
type Server struct {
// contains filtered or unexported fields
}
Server is the HTTP server wrapping mux many Dapr helpers.
func (*Server) AddBindingInvocationHandler ¶
func (s *Server) AddBindingInvocationHandler(route string, fn common.BindingInvocationHandler) error
AddBindingInvocationHandler appends provided binding invocation handler with its route to the service.
func (*Server) AddHealthCheckHandler ¶
func (s *Server) AddHealthCheckHandler(route string, fn common.HealthCheckHandler) error
AddHealthCheckHandler appends provided app health check handler.
func (*Server) AddServiceInvocationHandler ¶
func (s *Server) AddServiceInvocationHandler(route string, fn common.ServiceInvocationHandler) error
AddServiceInvocationHandler appends provided service invocation handler with its route to the service.
func (*Server) AddTopicEventHandler ¶
func (s *Server) AddTopicEventHandler(sub *common.Subscription, fn common.TopicEventHandler) error
AddTopicEventHandler appends provided event handler with it's name to the service.
func (*Server) GracefulStop ¶
func (*Server) RegisterActorImplFactoryContext ¶
func (s *Server) RegisterActorImplFactoryContext(f actor.FactoryContext, opts ...config.Option)
Source Files