Merge pull request #14825 from jmguzik/fix_streaming_pod_stats

Fix streaming for libpod/pods/stats endpoint

pkg/api/handlers/libpod/pods.go

@@ -530,8 +530,12 @@ func PodStats(w http.ResponseWriter, r *http.Request) {
 	query := struct {
 		NamesOrIDs []string `schema:"namesOrIDs"`
 		All        bool     `schema:"all"`
+		Stream     bool     `schema:"stream"`
+		Delay      int      `schema:"delay"`
 	}{
 		// default would go here
+		Delay:  5,
+		Stream: false,
 	}
 	if err := decoder.Decode(&query, r.URL.Query()); err != nil {
 		utils.Error(w, http.StatusBadRequest, fmt.Errorf("failed to parse parameters for %s: %w", r.URL.String(), err))
@@ -544,6 +548,10 @@ func PodStats(w http.ResponseWriter, r *http.Request) {
 		utils.InternalServerError(w, err)
 	}
 
+	var flush = func() {}
+	if flusher, ok := w.(http.Flusher); ok {
+		flush = flusher.Flush
+	}
 	// Collect the stats and send them over the wire.
 	containerEngine := abi.ContainerEngine{Libpod: runtime}
 	reports, err := containerEngine.PodStats(r.Context(), query.NamesOrIDs, options)
@@ -554,10 +562,35 @@ func PodStats(w http.ResponseWriter, r *http.Request) {
 			utils.Error(w, http.StatusNotFound, err)
 			return
 		}
-
 		utils.InternalServerError(w, err)
 		return
 	}
 
-	utils.WriteResponse(w, http.StatusOK, reports)
+	w.Header().Set("Content-Type", "application/json")
+	coder := json.NewEncoder(w)
+	coder.SetEscapeHTML(true)
+
+	if err := coder.Encode(reports); err != nil {
+		logrus.Infof("Error from %s %q : %v", r.Method, r.URL, err)
+	}
+	flush()
+	if query.Stream {
+		for {
+			select {
+			case <-r.Context().Done():
+				return
+			default:
+				time.Sleep(time.Duration(query.Delay) * time.Second)
+				reports, err = containerEngine.PodStats(r.Context(), query.NamesOrIDs, options)
+				if err != nil {
+					return
+				}
+				if err := coder.Encode(reports); err != nil {
+					logrus.Infof("Error from %s %q : %v", r.Method, r.URL, err)
+					return
+				}
+				flush()
+			}
+		}
+	}
 }

test/apiv2/40-pods.at

@@ -134,4 +134,6 @@ t GET libpod/pods/json?filters='{"label":["testl' 400 \
 t DELETE  libpod/pods/foo 200
 t DELETE "libpod/pods/foo (pod has already been deleted)" 404
 
+t_timeout 5 GET "libpod/pods/stats?stream=true&delay=1" 200
+
 # vim: filetype=sh

test/apiv2/test-apiv2

@@ -56,6 +56,9 @@ fi
 # Path to podman binary
 PODMAN_BIN=${PODMAN:-${CONTAINERS_HELPER_BINARY_DIR}/podman}
 
+# Timeout for streamed responses
+CURL_TIMEOUT=0
+
 # Cleanup handlers
 clean_up_server() {
     if [ -n "$service_pid" ]; then
@@ -216,6 +219,21 @@ function jsonify() {
     (IFS=','; echo "{${settings_out[*]}}")
 }
 
+#######
+#  t_timeout  #  Timeout wrapper for test helper
+#######
+function t_timeout() {
+    CURL_TIMEOUT=$1; shift
+    local min_runtime=$((CURL_TIMEOUT - 1))
+    start=`date +%s`
+    t $@
+    local end=`date +%s`
+    local runtime=$((end-start))
+    if ! [[ "$runtime" -ge "$min_runtime" ]]; then
+        die "Error: Streaming time should be greater or equal to '$min_runtime'"
+    fi
+}
+
 #######
 #  t  #  Main test helper
 #######
@@ -226,6 +244,12 @@ function t() {
     local content_type="application/json"
 
     local testname="$method $path"
+
+    if [[ $CURL_TIMEOUT != 0 ]]; then
+        local c_timeout=$CURL_TIMEOUT
+        curl_args+=("-m $CURL_TIMEOUT")
+        CURL_TIMEOUT=0 # 'consume' timeout
+    fi
     # POST and PUT requests may be followed by one or more key=value pairs.
     # Slurp the command line until we see a 3-digit status code.
     if [[ $method = "POST" || $method == "PUT" ]]; then
@@ -291,7 +315,7 @@ function t() {
                     -o $WORKDIR/curl.result.out "$url"); rc=$?; } || :
 
     # Any error from curl is instant bad news, from which we can't recover
-    if [[ $rc -ne 0 ]]; then
+    if [[ $rc -ne 0 ]] && [[ $c_timeout -eq 0 ]]; then
         die "curl failure ($rc) on $url - cannot continue"
     fi