From 9e48d5446534fef8353ed412cd656c2d3f4e2704 Mon Sep 17 00:00:00 2001
From: coral <shanhu5739@gmail.com>
Date: Fri, 29 Sep 2017 17:20:02 +0800
Subject: [PATCH 1/2] add diff and pdiff for conditions

---
 pkg/services/alerting/conditions/reducer.go   | 47 +++++++++++++++++++
 .../alerting/conditions/reducer_test.go       | 11 +++++
 public/app/features/alerting/alert_def.ts     |  2 +
 3 files changed, 60 insertions(+)

diff --git a/pkg/services/alerting/conditions/reducer.go b/pkg/services/alerting/conditions/reducer.go
index 0f396e2ffc3..81078b601e4 100644
--- a/pkg/services/alerting/conditions/reducer.go
+++ b/pkg/services/alerting/conditions/reducer.go
@@ -94,6 +94,53 @@ func (s *SimpleReducer) Reduce(series *tsdb.TimeSeries) null.Float {
 				value = (values[(length/2)-1] + values[length/2]) / 2
 			}
 		}
+	case "diff":
+		var (
+			points = series.Points
+			first  float64
+			i      int
+		)
+		// get the newest point
+		for i = len(points) - 1; i >= 0; i-- {
+			if points[i][0].Valid {
+				allNull = false
+				first = points[i][0].Float64
+				break
+			}
+		}
+		// get other points
+		points = points[0:i]
+		for i := len(points) - 1; i >= 0; i-- {
+			if points[i][0].Valid {
+				allNull = false
+				value = first - points[i][0].Float64
+				break
+			}
+		}
+	case "pdiff":
+		var (
+			points = series.Points
+			first  float64
+			i      int
+		)
+		// get the newest point
+		for i = len(points) - 1; i >= 0; i-- {
+			if points[i][0].Valid {
+				allNull = false
+				first = points[i][0].Float64
+				break
+			}
+		}
+		// get other points
+		points = points[0:i]
+		for i := len(points) - 1; i >= 0; i-- {
+			if points[i][0].Valid {
+				allNull = false
+				val := (first - points[i][0].Float64) / points[i][0].Float64 * 100
+				value = math.Abs(val)
+				break
+			}
+		}
 	}
 
 	if allNull {
diff --git a/pkg/services/alerting/conditions/reducer_test.go b/pkg/services/alerting/conditions/reducer_test.go
index ff6105a06ec..686a5b85478 100644
--- a/pkg/services/alerting/conditions/reducer_test.go
+++ b/pkg/services/alerting/conditions/reducer_test.go
@@ -80,6 +80,17 @@ func TestSimpleReducer(t *testing.T) {
 
 			So(reducer.Reduce(series).Float64, ShouldEqual, float64(3))
 		})
+
+		Convey("diff", func() {
+			result := testReducer("diff", 30, 40)
+			So(result, ShouldEqual, float64(10))
+		})
+
+		Convey("pdiff", func() {
+			result := testReducer("pdiff", 30, 40)
+			So(result, ShouldEqual, float64(33.33333333333333))
+		})
+
 	})
 }
 
diff --git a/public/app/features/alerting/alert_def.ts b/public/app/features/alerting/alert_def.ts
index 48cd4b056d9..cf6585bb6c6 100644
--- a/public/app/features/alerting/alert_def.ts
+++ b/public/app/features/alerting/alert_def.ts
@@ -49,6 +49,8 @@ var reducerTypes = [
   {text: 'count()', value: 'count'},
   {text: 'last()', value: 'last'},
   {text: 'median()', value: 'median'},
+  {text: 'diff()', value: 'diff'},
+  {text: 'pdiff()', value: 'pdiff'},
 ];
 
 var noDataModes = [

From 68ed4d45fa11d29527b5dfa15e7cc374df8a7ca7 Mon Sep 17 00:00:00 2001
From: coral <shanhu5739@gmail.com>
Date: Fri, 29 Sep 2017 18:14:17 +0800
Subject: [PATCH 2/2] change pdiff to percent_diff for conditions

---
 pkg/services/alerting/conditions/reducer.go      | 2 +-
 pkg/services/alerting/conditions/reducer_test.go | 4 ++--
 public/app/features/alerting/alert_def.ts        | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/pkg/services/alerting/conditions/reducer.go b/pkg/services/alerting/conditions/reducer.go
index 81078b601e4..6eaa21b958e 100644
--- a/pkg/services/alerting/conditions/reducer.go
+++ b/pkg/services/alerting/conditions/reducer.go
@@ -117,7 +117,7 @@ func (s *SimpleReducer) Reduce(series *tsdb.TimeSeries) null.Float {
 				break
 			}
 		}
-	case "pdiff":
+	case "percent_diff":
 		var (
 			points = series.Points
 			first  float64
diff --git a/pkg/services/alerting/conditions/reducer_test.go b/pkg/services/alerting/conditions/reducer_test.go
index 686a5b85478..f0147e9021a 100644
--- a/pkg/services/alerting/conditions/reducer_test.go
+++ b/pkg/services/alerting/conditions/reducer_test.go
@@ -86,8 +86,8 @@ func TestSimpleReducer(t *testing.T) {
 			So(result, ShouldEqual, float64(10))
 		})
 
-		Convey("pdiff", func() {
-			result := testReducer("pdiff", 30, 40)
+		Convey("percent_diff", func() {
+			result := testReducer("percent_diff", 30, 40)
 			So(result, ShouldEqual, float64(33.33333333333333))
 		})
 
diff --git a/public/app/features/alerting/alert_def.ts b/public/app/features/alerting/alert_def.ts
index cf6585bb6c6..51cbbd9691f 100644
--- a/public/app/features/alerting/alert_def.ts
+++ b/public/app/features/alerting/alert_def.ts
@@ -50,7 +50,7 @@ var reducerTypes = [
   {text: 'last()', value: 'last'},
   {text: 'median()', value: 'median'},
   {text: 'diff()', value: 'diff'},
-  {text: 'pdiff()', value: 'pdiff'},
+  {text: 'percent_diff()', value: 'percent_diff'},
 ];
 
 var noDataModes = [