fix window node so that when every==0, we can immediately emit the cu…

…rrent window

CHANGELOG.md

@@ -7,6 +7,7 @@
 ### Features
 
 - [#913](https://github.com/influxdata/kapacitor/issues/913): Add fillPeriod option to Window node, so that the first emit waits till the period has elapsed before emitting.
+- [#898](https://github.com/influxdata/kapacitor/issues/898): Now when the Window node every value is zero, the window will be emitted immediately for each new point.
 
 ### Bugfixes
 

integrations/data/TestStream_Window.srpl

@@ -6,6 +6,9 @@ rpname
 cpu,type=idle,host=serverB value=97.1 0000000001
 dbname
 rpname
+cpu,type=idle,host=serverC value=96.4 0000000001
+dbname
+rpname
 disk,type=sda,host=serverB value=39   0000000001
 dbname
 rpname
@@ -79,3 +82,6 @@ cpu,type=idle,host=serverA value=95.1 0000000012
 dbname
 rpname
 cpu,type=idle,host=serverB value=95.1 0000000012
+dbname
+rpname
+cpu,type=idle,host=serverC value=95.8 0000000012

integrations/streamer_test.go

@@ -648,6 +648,145 @@ stream
 	testStreamerWithOutput(t, "TestStream_Window", script, 13*time.Second, er, false, nil)
 }
 
+func TestStream_Window_Every_0(t *testing.T) {
+
+	var script = `
+var period = 10s
+// Emit the window on every point
+var every = 0s
+stream
+	|from()
+		.database('dbname')
+		.retentionPolicy('rpname')
+		.measurement('cpu')
+		.groupBy('host')
+	|window()
+		.period(period)
+		.every(every)
+	|count('value')
+	|window()
+		.period(10s)
+		.every(10s)
+	|httpOut('TestStream_Window')
+`
+
+	er := kapacitor.Result{
+		Series: imodels.Rows{
+			{
+				Name:    "cpu",
+				Tags:    map[string]string{"host": "serverA"},
+				Columns: []string{"time", "count"},
+				Values: [][]interface{}{
+					{
+						time.Date(1971, 1, 1, 0, 0, 0, 0, time.UTC),
+						1.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 1, 0, time.UTC),
+						2.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 2, 0, time.UTC),
+						3.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 3, 0, time.UTC),
+						4.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 4, 0, time.UTC),
+						5.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 5, 0, time.UTC),
+						6.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 6, 0, time.UTC),
+						7.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 7, 0, time.UTC),
+						8.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 8, 0, time.UTC),
+						9.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 9, 0, time.UTC),
+						10.0,
+					},
+				},
+			},
+			{
+				Name:    "cpu",
+				Tags:    map[string]string{"host": "serverB"},
+				Columns: []string{"time", "count"},
+				Values: [][]interface{}{
+					{
+						time.Date(1971, 1, 1, 0, 0, 0, 0, time.UTC),
+						1.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 1, 0, time.UTC),
+						2.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 2, 0, time.UTC),
+						3.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 3, 0, time.UTC),
+						4.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 4, 0, time.UTC),
+						5.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 5, 0, time.UTC),
+						6.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 6, 0, time.UTC),
+						7.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 7, 0, time.UTC),
+						8.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 8, 0, time.UTC),
+						9.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 9, 0, time.UTC),
+						10.0,
+					},
+				},
+			},
+			{
+				Name:    "cpu",
+				Tags:    map[string]string{"host": "serverC"},
+				Columns: []string{"time", "count"},
+				Values: [][]interface{}{
+					{
+						time.Date(1971, 1, 1, 0, 0, 0, 0, time.UTC),
+						1.0,
+					},
+					{
+						time.Date(1971, 1, 1, 0, 0, 5, 0, time.UTC),
+						2.0,
+					},
+				},
+			},
+		},
+	}
+
+	testStreamerWithOutput(t, "TestStream_Window", script, 13*time.Second, er, false, nil)
+}
+
 func TestStream_Window_Overlapping(t *testing.T) {
 
 	var script = `

pipeline/window.go

@@ -31,6 +31,7 @@ type WindowNode struct {
 	// The period, or length in time, of the window.
 	Period time.Duration
 	// How often the current window is emitted into the pipeline.
+	// If equal to zero, then every new point will emit the current window.
 	Every time.Duration
 	// Whether to align the window edges with the zero time
 	// tick:ignore

window.go

@@ -69,6 +69,13 @@ func (w *WindowNode) runWindow([]byte) error {
 			}
 			windows[p.Group] = wnd
 		}
+		if w.w.Every == 0 {
+			// Insert the point now since we know we do not need to wait.
+			wnd.buf.insert(p)
+			// We are emitting on every point, so the nextEmit is always
+			// the time of the current point.
+			wnd.nextEmit = p.Time
+		}
 		if !p.Time.Before(wnd.nextEmit) {
 			points := wnd.emit(p.Time)
 			// Send window to all children
@@ -81,7 +88,9 @@ func (w *WindowNode) runWindow([]byte) error {
 			}
 			w.timer.Resume()
 		}
-		wnd.buf.insert(p)
+		if w.w.Every != 0 {
+			wnd.buf.insert(p)
+		}
 		w.timer.Stop()
 	}
 	return nil