Update /_example/basic/3-router example (#157)

ThreeDotsLabs · Nov 1, 2019 · dcfc25d · dcfc25d
1 parent c72e26a
commit dcfc25d
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Showing 3 changed files with 16 additions and 4 deletions.
diff --git a/_examples/basic/3-router/go.mod b/_examples/basic/3-router/go.mod
@@ -1,3 +1,3 @@
 module main.go
 
-require github.com/ThreeDotsLabs/watermill v1.0.0-rc.2
+require github.com/ThreeDotsLabs/watermill v1.0.1-0.20191022063524-9ce413590da0
diff --git a/_examples/basic/3-router/go.sum b/_examples/basic/3-router/go.sum
@@ -1,5 +1,5 @@
-github.com/ThreeDotsLabs/watermill v1.0.0-rc.2 h1:DCKR8kSLHUyZny6LiKtO7h+IZPMo0t9x786FOZmoAh4=
-github.com/ThreeDotsLabs/watermill v1.0.0-rc.2/go.mod h1:gjVFKc8aN+vmEHw3pA0kh4mmuwHe02nyfghb6IWWiKE=
+github.com/ThreeDotsLabs/watermill v1.0.1-0.20191022063524-9ce413590da0 h1:3Pf5VPjh+tigAZLhZgyZ4vHm23dZmVYAsy26qs8Zu28=
+github.com/ThreeDotsLabs/watermill v1.0.1-0.20191022063524-9ce413590da0/go.mod h1:gjVFKc8aN+vmEHw3pA0kh4mmuwHe02nyfghb6IWWiKE=
 github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=

diff --git a/_examples/basic/3-router/main.go b/_examples/basic/3-router/main.go
@@ -30,6 +30,7 @@ func main() {
 	// You can also close the router by just calling `r.Close()`.
 	router.AddPlugin(plugin.SignalsHandler)
 
+	// Router level middleware are executed for every message sent to the router
 	router.AddMiddleware(
 		// CorrelationID will copy the correlation id from the incoming message's metadata to the produced messages
 		middleware.CorrelationID,
@@ -54,7 +55,8 @@ func main() {
 	// Producing some incoming messages in background
 	go publishMessages(pubSub)
 
-	router.AddHandler(
+	// AddHandler returns a handler which can be used to add handler level middleware
+	handler := router.AddHandler(
 		"struct_handler",          // handler name, must be unique
 		"incoming_messages_topic", // topic from which we will read events
 		pubSub,
@@ -63,6 +65,16 @@ func main() {
 		structHandler{}.Handler,
 	)
 
+	// Handler level middleware is only executed for a specific handler
+	// Such middleware can be added the same way the router level ones
+	handler.AddMiddleware(func(h message.HandlerFunc) message.HandlerFunc {
+		return func(message *message.Message) ([]*message.Message, error) {
+			log.Println("executing handler specific middleware for ", message.UUID)
+
+			return h(message)
+		}
+	})
+
 	// just for debug, we are printing all messages received on `incoming_messages_topic`
 	router.AddNoPublisherHandler(
 		"print_incoming_messages",