Expose scale-function endpoint

- exposes scale-function endpoint for use with faas-idler, this
is protected by auth when enabled.

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

api-docs/swagger.yml

@@ -197,6 +197,33 @@ paths:
           description: Function not found
         '500':
           description: Error connecting to function
+  '/system/scale-function/{functionName}':
+    get:
+      summary: Scale a function
+      parameters:
+        - in: path
+          name: functionName
+          description: Function name
+          type: string
+          required: true
+        - in: body
+          name: input
+          description: Function to scale plus replica count
+          schema:
+            type: string
+            format: binary
+            example:
+              '{"service": "hello-world", "replicas": 10}'
+          required: false
+      responses:
+        '200':
+          description: Scaling OK
+        '202':
+          description: Scaling OK
+        '404':
+          description: Function not found
+        '500':
+          description: Error scaling function
   '/system/function/{functionName}':
     get:
       summary: Get a summary of an OpenFaaS function

gateway/server.go

@@ -101,6 +101,8 @@ func main() {
 	faasHandlers.ListFunctions = metrics.AddMetricsHandler(faasHandlers.ListFunctions, prometheusQuery)
 	faasHandlers.Proxy = handlers.MakeCallIDMiddleware(faasHandlers.Proxy)
 
+	faasHandlers.ScaleFunction = handlers.MakeForwardingProxyHandler(reverseProxy, forwardingNotifiers, urlResolver)
+
 	if credentials != nil {
 		faasHandlers.UpdateFunction =
 			handlers.DecorateWithBasicAuth(faasHandlers.UpdateFunction, credentials)
@@ -110,6 +112,9 @@ func main() {
 			handlers.DecorateWithBasicAuth(faasHandlers.DeployFunction, credentials)
 		faasHandlers.ListFunctions =
 			handlers.DecorateWithBasicAuth(faasHandlers.ListFunctions, credentials)
+		faasHandlers.ScaleFunction =
+			handlers.DecorateWithBasicAuth(faasHandlers.ScaleFunction, credentials)
+
 	}
 
 	r := mux.NewRouter()
@@ -141,6 +146,7 @@ func main() {
 	r.HandleFunc("/system/functions", faasHandlers.DeployFunction).Methods(http.MethodPost)
 	r.HandleFunc("/system/functions", faasHandlers.DeleteFunction).Methods(http.MethodDelete)
 	r.HandleFunc("/system/functions", faasHandlers.UpdateFunction).Methods(http.MethodPut)
+	r.HandleFunc("/system/scale-function/{name:[-a-zA-Z_0-9]+}", faasHandlers.ScaleFunction).Methods(http.MethodPost)
 
 	if faasHandlers.QueuedProxy != nil {
 		r.HandleFunc("/async-function/{name:[-a-zA-Z_0-9]+}/", faasHandlers.QueuedProxy).Methods(http.MethodPost)

gateway/types/handler_set.go

@@ -17,4 +17,7 @@ type HandlerSet struct {
 
 	// AsyncReport - report a deferred execution result
 	AsyncReport http.HandlerFunc
+
+	// ScaleFunction allows a function to be scaled
+	ScaleFunction http.HandlerFunc
 }