gauge shift

Author: sokil

README.md

@@ -50,15 +50,23 @@ value=1&sampleRate=1
 | sampleRate | Sample rate to skip metrics          | Optional. Default to 1: accept all |
 
 ### Gauge
+
+Gauge is an arbitrary value. If the gauge is not updated at the next flush, it will send the previous value.
+Gauge also may be set relatively to previously stored value.
+
+Absolute value:
 ```
 POST /gauge/{key}
 X-JWT-Token: {tokenString}
 value=1
 ```
 
-| Parameter  | Description                          | Default value                      |
-|------------|--------------------------------------|------------------------------------|
-| value      | Value                                | Optional. Default 1                |
+Shift of previous value:
+```
+POST /gauge/{key}
+X-JWT-Token: {tokenString}
+shift=-1
+```
 
 ### Timing
 ```
@@ -114,7 +122,7 @@ Intel(R) Core(TM) i5-2450M CPU @ 2.50GHz Dual Core / 8 GB RAM
 Siege test:
 
 ```
-$ time siege -c 255 -r 255 -b -H 'X-JWT-Token:eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJzdGF0c2QtcmVzdC1zZXJ2ZXIiLCJpYXQiOjE1MDY5NzI1ODAsImV4cCI6MTg4NTY2Mzc4MCwiYXVkIjoiaHR0cHM6Ly9naXRodWIuY29tL3Nva2lsL3N0YXRzZC1yZXN0LXNlcnZlciIsInN1YiI6InNva2lsIn0.sOb0ccRBnN1u9IP2jhJrcNod14G5t-jMHNb_fsWov5c' "http://127.0.0.1:8080/count/a.b.c.d POST"
+$ time siege -c 255 -r 255 -b -H 'X-JWT-Token:eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJzdGF0c2QtcmVzdC1zZXJ2ZXIiLCJpYXQiOjE1MDY5NzI1ODAsImV4cCI6MTg4NTY2Mzc4MCwiYXVkIjoiaHR0cHM6Ly9naXRodWIuY29tL3Nva2lsL3N0YXRzZC1yZXN0LXNlcnZlciIsInN1YiI6InNva2lsIn0.sOb0ccRBnN1u9IP2jhJrcNod14G5t-jMHNb_fsWov5c' "http://127.0.0.1:8080/count/a.b.c.d POST value=42"
   ** SIEGE 4.0.2
   ** Preparing 255 concurrent users for battle.
   The server is now under siege...

main.go

@@ -211,19 +211,35 @@ func handleGaugeRequest(w http.ResponseWriter, r *http.Request) {
 	vars := mux.Vars(r)
 	key := vars["key"]
 
-	// get delta
+	// get gauge shift
+	shiftPostFormValue := r.PostFormValue("shift")
+	if shiftPostFormValue != "" {
+		// get value
+		value, err := strconv.Atoi(shiftPostFormValue)
+		if err != nil {
+			http.Error(w, "Invalid gauge shift specified", 400)
+		}
+		// send request
+		statsdClient.GaugeShift(key, value)
+		return
+	}
+
+	// get gauge value
 	var value = 1
 	valuePostFormValue := r.PostFormValue("value")
 	if valuePostFormValue != "" {
+		// get value
 		var err error
 		value, err = strconv.Atoi(valuePostFormValue)
 		if err != nil {
-			http.Error(w, "Invalid delta specified", 400)
+			http.Error(w, "Invalid gauge value specified", 400)
 		}
 	}
 
-	// send request
+	// send gauge value request
 	statsdClient.Gauge(key, value)
+
+
 }
 
 // Handle StatsD Timing request
@@ -259,14 +275,14 @@ func handleSetRequest(w http.ResponseWriter, r *http.Request) {
 	vars := mux.Vars(r)
 	key := vars["key"]
 
-	// get delta
+	// get set value
 	var value = 1
 	valuePostFormValue := r.PostFormValue("value")
 	if valuePostFormValue != "" {
 		var err error
 		value, err = strconv.Atoi(valuePostFormValue)
 		if err != nil {
-			http.Error(w, "Invalid delta specified", 400)
+			http.Error(w, "Invalid set value specified", 400)
 		}
 	}