Add QueueName to async requests

The queue's name will be consumed by the queue worker to
publish to other topics / slow queues.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

gateway/queue/types.go

@@ -3,21 +3,47 @@
 
 package queue
 
-import "net/url"
-import "net/http"
+import (
+	"net/http"
+	"net/url"
+)
 
 // Request for asynchronous processing
 type Request struct {
-	Header      http.Header
-	Host        string
-	Body        []byte
-	Method      string
-	Path        string
+	// Header from HTTP request
+	Header http.Header
+
+	// Host from HTTP request
+	Host string
+
+	// Body from HTTP request to use for invocation
+	Body []byte
+
+	// Method from HTTP request
+	Method string
+
+	// Path from HTTP request
+	Path string
+
+	// QueryString from HTTP request
 	QueryString string
-	Function    string
+
+	// Function name to invoke
+	Function string
+
+	// QueueName to publish the request to, leave blank
+	// for default.
+	QueueName string
+
+	// Used by queue worker to submit a result
 	CallbackURL *url.URL `json:"CallbackUrl"`
 }
 
+// RequestQueuer can public a request to be executed asynchronously
+type RequestQueuer interface {
+	Queue(req *Request) error
+}
+
 // CanQueueRequests can take on asynchronous requests
 type CanQueueRequests interface {
 	Queue(req *Request) error