Added handling custom metrics to resource consumer.

test/images/resource-consumer/README.md

 # Resource Consumer
 
 ## Overview
-
 Resource Consumer is a tool which allows to generate cpu/memory utilization in a container.
 The reason why it was created is testing kubernetes autoscaling.
 Resource Consumer can help with autoscaling tests for:
@@ -10,8 +9,7 @@ Resource Consumer can help with autoscaling tests for:
 - vertical autoscaling of pod - changing its resource limits.
 
 ## Usage
-
-Resource Consumer starts an HTTP server and handle sended requests.
+Resource Consumer starts an HTTP server and handle sent requests.
 It listens on port given as a flag (default 8080).
 Action of consuming resources is send to the container by a POST http request.
 Each http request creates new process.
@@ -20,12 +18,10 @@ Http request handler is in file resource_consumer_handler.go
 The container consumes specified amount of resources:
 
 - CPU in millicores,
-- Memory in megabytes.
-
-
+- Memory in megabytes,
+- Fake custom metrics.
 
 ###Consume CPU http request
-
 - suffix "ConsumeCPU",
 - parameters "millicores" and "durationSec".
 
@@ -36,13 +32,19 @@ and if consumption is too high binary sleeps for 10 millisecond.
 One replica of Resource Consumer cannot consume more that 1 cpu.
 
 ###Consume Memory http request
-
 - suffix "ConsumeMem",
 - parameters "megabytes" and "durationSec".
 
 Consumes specified amount of megabytes for durationSec seconds.
 Consume Memory uses stress tool (stress -m 1 --vm-bytes megabytes --vm-hang 0 -t durationSec).
-Request leading to consumig more memory then container limit will be ignored. 
+Request leading to consuming more memory then container limit will be ignored.
+
+###Bump value of a fake custom metric
+- suffix "BumpMetric",
+- parameters "metric", "delta" and "durationSec".
+
+Bumps metric with given name by delta for durationSec seconds.
+Custom metrics in Prometheus format are exposed on "/metrics" endpoint.
 
 ###CURL example
 ```console

test/images/resource-consumer/resource_consumer.go

@@ -27,6 +27,6 @@ var port = flag.Int("port", 8080, "Port number.")
 
 func main() {
 	flag.Parse()
-	var resourceConsumerHandler ResourceConsumerHandler
+	resourceConsumerHandler := NewResourceConsumerHandler()
 	log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", *port), resourceConsumerHandler))
 }

test/images/resource-consumer/resource_consumer_handler.go

@@ -21,6 +21,8 @@ import (
 	"net/http"
 	"net/url"
 	"strconv"
+	"sync"
+	"time"
 )
 
 const (
@@ -30,17 +32,34 @@ const (
 	notGivenFunctionArgument  = "not given function argument"
 	consumeCPUAddress         = "/ConsumeCPU"
 	consumeMemAddress         = "/ConsumeMem"
+	bumpMetricAddress         = "/BumpMetric"
 	getCurrentStatusAddress   = "/GetCurrentStatus"
+	metricsAddress            = "/metrics"
 	millicoresQuery           = "millicores"
 	megabytesQuery            = "megabytes"
+	metricNameQuery           = "metric"
+	deltaQuery                = "delta"
 	durationSecQuery          = "durationSec"
 )
 
-type ResourceConsumerHandler struct{}
+type ResourceConsumerHandler struct {
+	metrics     map[string]float64
+	metricsLock sync.Mutex
+}
+
+func NewResourceConsumerHandler() ResourceConsumerHandler {
+	return ResourceConsumerHandler{metrics: map[string]float64{}}
+}
 
 func (handler ResourceConsumerHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	// handle exposing metrics in Prometheus format (both GET & POST)
+	if req.URL.Path == metricsAddress {
+		handler.handleMetrics(w)
+		return
+	}
 	if req.Method != "POST" {
 		http.Error(w, badRequest, http.StatusBadRequest)
+		return
 	}
 	// parsing POST request data and URL data
 	if err := req.ParseForm(); err != nil {
@@ -62,6 +81,11 @@ func (handler ResourceConsumerHandler) ServeHTTP(w http.ResponseWriter, req *htt
 		handler.handleGetCurrentStatus(w)
 		return
 	}
+	// handle bumpMetric
+	if req.URL.Path == bumpMetricAddress {
+		handler.handleBumpMetric(w, req.Form)
+		return
+	}
 	http.Error(w, unknownFunction, http.StatusNotFound)
 }
 
@@ -72,21 +96,20 @@ func (handler ResourceConsumerHandler) handleConsumeCPU(w http.ResponseWriter, q
 	if durationSecString == "" || millicoresString == "" {
 		http.Error(w, notGivenFunctionArgument, http.StatusBadRequest)
 		return
-	} else {
-		// convert data (strings to ints) for consumeCPU
-		durationSec, durationSecError := strconv.Atoi(durationSecString)
-		millicores, millicoresError := strconv.Atoi(millicoresString)
-		if durationSecError != nil || millicoresError != nil {
-			http.Error(w, incorrectFunctionArgument, http.StatusBadRequest)
-			return
-		}
-		go ConsumeCPU(millicores, durationSec)
-		fmt.Fprintln(w, consumeCPUAddress[1:])
-		fmt.Fprintln(w, millicores, millicoresQuery)
-		fmt.Fprintln(w, durationSec, durationSecQuery)
+	}
 
+	// convert data (strings to ints) for consumeCPU
+	durationSec, durationSecError := strconv.Atoi(durationSecString)
+	millicores, millicoresError := strconv.Atoi(millicoresString)
+	if durationSecError != nil || millicoresError != nil {
+		http.Error(w, incorrectFunctionArgument, http.StatusBadRequest)
+		return
 	}
 
+	go ConsumeCPU(millicores, durationSec)
+	fmt.Fprintln(w, consumeCPUAddress[1:])
+	fmt.Fprintln(w, millicores, millicoresQuery)
+	fmt.Fprintln(w, durationSec, durationSecQuery)
 }
 
 func (handler ResourceConsumerHandler) handleConsumeMem(w http.ResponseWriter, query url.Values) {
@@ -96,19 +119,20 @@ func (handler ResourceConsumerHandler) handleConsumeMem(w http.ResponseWriter, q
 	if durationSecString == "" || megabytesString == "" {
 		http.Error(w, notGivenFunctionArgument, http.StatusBadRequest)
 		return
-	} else {
-		// convert data (strings to ints) for consumeMem
-		durationSec, durationSecError := strconv.Atoi(durationSecString)
-		megabytes, megabytesError := strconv.Atoi(megabytesString)
-		if durationSecError != nil || megabytesError != nil {
-			http.Error(w, incorrectFunctionArgument, http.StatusBadRequest)
-			return
-		}
-		go ConsumeMem(megabytes, durationSec)
-		fmt.Fprintln(w, consumeMemAddress[1:])
-		fmt.Fprintln(w, megabytes, megabytesQuery)
-		fmt.Fprintln(w, durationSec, durationSecQuery)
 	}
+
+	// convert data (strings to ints) for consumeMem
+	durationSec, durationSecError := strconv.Atoi(durationSecString)
+	megabytes, megabytesError := strconv.Atoi(megabytesString)
+	if durationSecError != nil || megabytesError != nil {
+		http.Error(w, incorrectFunctionArgument, http.StatusBadRequest)
+		return
+	}
+
+	go ConsumeMem(megabytes, durationSec)
+	fmt.Fprintln(w, consumeMemAddress[1:])
+	fmt.Fprintln(w, megabytes, megabytesQuery)
+	fmt.Fprintln(w, durationSec, durationSecQuery)
 }
 
 func (handler ResourceConsumerHandler) handleGetCurrentStatus(w http.ResponseWriter) {
@@ -116,3 +140,54 @@ func (handler ResourceConsumerHandler) handleGetCurrentStatus(w http.ResponseWri
 	fmt.Fprintln(w, "Warning: not implemented!")
 	fmt.Fprint(w, getCurrentStatusAddress[1:])
 }
+
+func (handler ResourceConsumerHandler) handleMetrics(w http.ResponseWriter) {
+	handler.metricsLock.Lock()
+	defer handler.metricsLock.Unlock()
+	for k, v := range handler.metrics {
+		fmt.Fprintf(w, "# HELP %s info message.\n", k)
+		fmt.Fprintf(w, "# TYPE %s gauge\n", k)
+		fmt.Fprintf(w, "%s %f\n", k, v)
+	}
+}
+
+func (handler ResourceConsumerHandler) bumpMetric(metric string, delta float64, duration time.Duration) {
+	handler.metricsLock.Lock()
+	if _, ok := handler.metrics[metric]; ok {
+		handler.metrics[metric] += delta
+	} else {
+		handler.metrics[metric] = delta
+	}
+	handler.metricsLock.Unlock()
+
+	time.Sleep(duration)
+
+	handler.metricsLock.Lock()
+	handler.metrics[metric] -= delta
+	handler.metricsLock.Unlock()
+}
+
+func (handler ResourceConsumerHandler) handleBumpMetric(w http.ResponseWriter, query url.Values) {
+	// geting string data for handleBumpMetric
+	metric := query.Get(metricNameQuery)
+	deltaString := query.Get(deltaQuery)
+	durationSecString := query.Get(durationSecQuery)
+	if durationSecString == "" || metric == "" || deltaString == "" {
+		http.Error(w, notGivenFunctionArgument, http.StatusBadRequest)
+		return
+	}
+
+	// convert data (strings to ints/floats) for handleBumpMetric
+	durationSec, durationSecError := strconv.Atoi(durationSecString)
+	delta, deltaError := strconv.ParseFloat(deltaString, 64)
+	if durationSecError != nil || deltaError != nil {
+		http.Error(w, incorrectFunctionArgument, http.StatusBadRequest)
+		return
+	}
+
+	go handler.bumpMetric(metric, delta, time.Duration(durationSec)*time.Second)
+	fmt.Fprintln(w, bumpMetricAddress[1:])
+	fmt.Fprintln(w, metric, metricNameQuery)
+	fmt.Fprintln(w, delta, deltaQuery)
+	fmt.Fprintln(w, durationSec, durationSecQuery)
+}