Merge pull request #10517 from cdoern/master

API one-shot query implementation/handling

pkg/api/handlers/compat/containers_stats.go

@@ -23,6 +23,7 @@ func StatsContainer(w http.ResponseWriter, r *http.Request) {
 
 	query := struct {
 		Stream  bool `schema:"stream"`
+		OneShot bool `schema:"one-shot"` //added schema for one shot
 	}{
 		Stream: true,
 	}
@@ -30,6 +31,10 @@ func StatsContainer(w http.ResponseWriter, r *http.Request) {
 		utils.Error(w, "Something went wrong.", http.StatusBadRequest, errors.Wrapf(err, "failed to parse parameters for %s", r.URL.String()))
 		return
 	}
+	if query.Stream && query.OneShot { // mismatch. one-shot can only be passed with stream=false
+		utils.Error(w, "invalid combination of stream and one-shot", http.StatusBadRequest, define.ErrInvalidArg)
+		return
+	}
 
 	name := utils.GetName(r)
 	ctnr, err := runtime.LookupContainer(name)
@@ -56,6 +61,16 @@ func StatsContainer(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	coder := json.NewEncoder(w)
+	// Write header and content type.
+	w.WriteHeader(http.StatusOK)
+	w.Header().Add("Content-Type", "application/json")
+	if flusher, ok := w.(http.Flusher); ok {
+		flusher.Flush()
+	}
+
+	// Setup JSON encoder for streaming.
+	coder.SetEscapeHTML(true)
 	var preRead time.Time
 	var preCPUStats CPUStats
 	if query.Stream {
@@ -75,17 +90,6 @@ func StatsContainer(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	// Write header and content type.
-	w.WriteHeader(http.StatusOK)
-	w.Header().Add("Content-Type", "application/json")
-	if flusher, ok := w.(http.Flusher); ok {
-		flusher.Flush()
-	}
-
-	// Setup JSON encoder for streaming.
-	coder := json.NewEncoder(w)
-	coder.SetEscapeHTML(true)
-
 streamLabel: // A label to flatten the scope
 	select {
 	case <-r.Context().Done():
@@ -199,7 +203,7 @@ streamLabel: // A label to flatten the scope
 			flusher.Flush()
 		}
 
-		if !query.Stream {
+		if !query.Stream || query.OneShot {
 			return
 		}
 

pkg/api/server/register_containers.go

@@ -375,6 +375,11 @@ func (s *APIServer) registerContainersHandlers(r *mux.Router) error {
 	//    type: boolean
 	//    default: true
 	//    description: Stream the output
+	//  - in: query
+	//    name: one-shot
+	//    type: boolean
+	//    default: false
+	//    description: Provide a one-shot response in which preCPU stats are blank, resulting in a single cycle return.
 	// produces:
 	// - application/json
 	// responses:

test/apiv2/python/rest_api/test_v2_0_0_container.py

@@ -30,6 +30,10 @@ class ContainerTestCase(APITestCase):
         self.assertIn(r.status_code, (200, 409), r.text)
         if r.status_code == 200:
             self.assertId(r.content)
+        r = requests.get(self.uri(self.resolve_container("/containers/{}/stats?stream=false&one-shot=true")))
+        self.assertIn(r.status_code, (200, 409), r.text)
+        if r.status_code == 200:
+            self.assertId(r.content)
 
     def test_delete(self):
         r = requests.delete(self.uri(self.resolve_container("/containers/{}")))