Query Prometheus API for stats.

Signed-off-by: Alex Ellis <alexellis2@gmail.com>

gateway/handlers/reader.go

@@ -16,8 +16,6 @@ import (
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/api/types/filters"
 	"github.com/docker/docker/client"
-	"github.com/prometheus/client_golang/prometheus"
-	io_prometheus_client "github.com/prometheus/client_model/go"
 )
 
 // MakeFunctionReader gives a summary of Function structs with Docker service stats overlaid with Prometheus counters.
@@ -41,8 +39,10 @@ func MakeFunctionReader(metricsOptions metrics.MetricOptions, c *client.Client)
 		for _, service := range services {
 
 			if len(service.Spec.TaskTemplate.ContainerSpec.Labels["function"]) > 0 {
-				invocations := getCounterValue(service.Spec.Name, "200", &metricsOptions) +
-					getCounterValue(service.Spec.Name, "500", &metricsOptions)
+
+				// Ping counters
+				// getCounterValue(service.Spec.Name, "200", &metricsOptions)
+				// getCounterValue(service.Spec.Name, "500", &metricsOptions)
 
 				var envProcess string
 
@@ -55,7 +55,7 @@ func MakeFunctionReader(metricsOptions metrics.MetricOptions, c *client.Client)
 				f := requests.Function{
 					Name:            service.Spec.Name,
 					Image:           service.Spec.TaskTemplate.ContainerSpec.Image,
-					InvocationCount: invocations,
+					InvocationCount: 0,
 					Replicas:        *service.Spec.Mode.Replicated.Replicas,
 					EnvProcess:      envProcess,
 				}
@@ -71,18 +71,18 @@ func MakeFunctionReader(metricsOptions metrics.MetricOptions, c *client.Client)
 	}
 }
 
-func getCounterValue(service string, code string, metricsOptions *metrics.MetricOptions) float64 {
+// func getCounterValue(service string, code string, metricsOptions *metrics.MetricOptions) float64 {
 
-	metric, err := metricsOptions.GatewayFunctionInvocation.
-		GetMetricWith(prometheus.Labels{"function_name": service, "code": code})
+// 	metric, err := metricsOptions.GatewayFunctionInvocation.
+// 		GetMetricWith(prometheus.Labels{"function_name": service, "code": code})
 
-	if err != nil {
-		return 0
-	}
+// 	if err != nil {
+// 		return 0
+// 	}
 
-	// Get the metric's value from ProtoBuf interface (idea via Julius Volz)
-	var protoMetric io_prometheus_client.Metric
-	metric.Write(&protoMetric)
-	invocations := protoMetric.GetCounter().GetValue()
-	return invocations
-}
+// 	// Get the metric's value from ProtoBuf interface (idea via Julius Volz)
+// 	var protoMetric io_prometheus_client.Metric
+// 	metric.Write(&protoMetric)
+// 	invocations := protoMetric.GetCounter().GetValue()
+// 	return invocations
+// }

gateway/metrics/add_metrics.go

@@ -0,0 +1,110 @@
+package metrics
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"net/http/httptest"
+	"strconv"
+
+	"github.com/alexellis/faas/gateway/requests"
+)
+
+func makeClient() http.Client {
+	// Fine-tune the client to fail fast.
+	return http.Client{}
+}
+
+// AddMetricsHandler wraps a http.HandlerFunc with Prometheus metrics
+func AddMetricsHandler(handler http.HandlerFunc, host string, port int) http.HandlerFunc {
+	client := makeClient()
+
+	prometheusQuery := NewPrometheusQuery(host, port, &client)
+	return func(w http.ResponseWriter, r *http.Request) {
+		// log.Printf("Calling upstream for function info\n")
+
+		recorder := httptest.NewRecorder()
+		handler.ServeHTTP(recorder, r)
+		upstreamCall := recorder.Result()
+
+		if upstreamCall.Body == nil {
+			return
+		}
+		defer upstreamCall.Body.Close()
+
+		if recorder.Code != http.StatusOK {
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Write([]byte(fmt.Sprintf("Error pulling metrics from provider/backend. Status code: %d", recorder.Code)))
+			return
+		}
+
+		upstreamBody, _ := ioutil.ReadAll(upstreamCall.Body)
+		var functions []requests.Function
+
+		err := json.Unmarshal(upstreamBody, &functions)
+		if err != nil {
+			log.Println(err)
+
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Write([]byte("Error parsing metrics from upstream provider/backend."))
+			return
+		}
+
+		// log.Printf("Querying Prometheus API\n")
+		// `sum(gateway_function_invocation_total{function_name=~".*", code=~".*"}) by (function_name, code)`)
+		expr := "sum(gateway_function_invocation_total%7Bfunction_name%3D~%22.*%22%2C+code%3D~%22.*%22%7D)+by+(function_name%2C+code)"
+		results, fetchErr := prometheusQuery.Fetch(expr)
+		if fetchErr != nil {
+			log.Printf("Error querying Prometheus API: %s\n", fetchErr.Error())
+
+			w.WriteHeader(http.StatusOK)
+			w.Write(upstreamBody)
+			return
+		}
+
+		mixIn(&functions, results)
+
+		bytesOut, marshalErr := json.Marshal(functions)
+		if marshalErr != nil {
+			log.Println(marshalErr)
+			return
+		}
+
+		// log.Printf("Writing bytesOut: %s\n", bytesOut)
+		w.WriteHeader(http.StatusOK)
+		w.Write(bytesOut)
+	}
+}
+
+func mixIn(functions *[]requests.Function, metrics *VectorQueryResponse) {
+	if functions == nil {
+		return
+	}
+
+	// Ensure values are empty first.
+	for i := range *functions {
+		(*functions)[i].InvocationCount = 0
+	}
+
+	for i, function := range *functions {
+		for _, v := range metrics.Data.Result {
+
+			if v.Metric.FunctionName == function.Name {
+				metricValue := v.Value[1]
+				switch metricValue.(type) {
+				case string:
+					// log.Println("String")
+					f, strconvErr := strconv.ParseFloat(metricValue.(string), 64)
+					if strconvErr != nil {
+						log.Printf("Unable to convert value for metric: %s\n", strconvErr)
+						continue
+					}
+					(*functions)[i].InvocationCount += f
+					break
+				}
+			}
+		}
+	}
+}

gateway/metrics/prometheus_query.go

@@ -0,0 +1,63 @@
+package metrics
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+)
+
+// PrometheusQuery a PrometheusQuery
+type PrometheusQuery struct {
+	Port   int
+	Host   string
+	Client *http.Client
+}
+
+// NewPrometheusQuery create a NewPrometheusQuery
+func NewPrometheusQuery(host string, port int, client *http.Client) PrometheusQuery {
+	return PrometheusQuery{
+		Client: client,
+		Host:   host,
+		Port:   port,
+	}
+}
+
+// Fetch queries aggregated stats
+func (q *PrometheusQuery) Fetch(query string) (*VectorQueryResponse, error) {
+
+	req, reqErr := http.NewRequest("GET", fmt.Sprintf("http://%s:%d/api/v1/query/?query=%s", q.Host, q.Port, query), nil)
+	if reqErr != nil {
+		return nil, reqErr
+	}
+	res, getErr := q.Client.Do(req)
+	if getErr != nil {
+		return nil, getErr
+	}
+	defer res.Body.Close()
+	bytesOut, readErr := ioutil.ReadAll(res.Body)
+	if readErr != nil {
+		return nil, readErr
+	}
+
+	var values VectorQueryResponse
+
+	unmarshalErr := json.Unmarshal(bytesOut, &values)
+	if unmarshalErr != nil {
+		return nil, unmarshalErr
+	}
+
+	return &values, nil
+}
+
+type VectorQueryResponse struct {
+	Data struct {
+		Result []struct {
+			Metric struct {
+				Code         string `json:"code"`
+				FunctionName string `json:"function_name"`
+			}
+			Value []interface{} `json:"value"`
+		}
+	}
+}

gateway/server.go

@@ -114,6 +114,8 @@ func main() {
 		faasHandlers.AsyncReport = internalHandlers.MakeAsyncReport(metricsOptions)
 	}
 
+	listFunctions := metrics.AddMetricsHandler(faasHandlers.ListFunctions, config.PrometheusHost, config.PrometheusPort)
+
 	r := mux.NewRouter()
 
 	// r.StrictSlash(false)	// This didn't work, so register routes twice.
@@ -121,7 +123,7 @@ func main() {
 	r.HandleFunc("/function/{name:[-a-zA-Z_0-9]+}/", faasHandlers.Proxy)
 
 	r.HandleFunc("/system/alert", faasHandlers.Alert)
-	r.HandleFunc("/system/functions", faasHandlers.ListFunctions).Methods("GET")
+	r.HandleFunc("/system/functions", listFunctions).Methods("GET")
 	r.HandleFunc("/system/functions", faasHandlers.DeployFunction).Methods("POST")
 	r.HandleFunc("/system/functions", faasHandlers.DeleteFunction).Methods("DELETE")
 

gateway/tests/config_test.go

@@ -73,3 +73,81 @@ func TestRead_ReadAndWriteTimeoutConfig(t *testing.T) {
 		t.Fail()
 	}
 }
+
+func TestRead_UseNATSDefaultsToOff(t *testing.T) {
+	defaults := NewEnvBucket()
+	readConfig := types.ReadConfig{}
+
+	config := readConfig.Read(defaults)
+
+	if config.UseNATS() == true {
+		t.Log("NATS is supposed to be off by default")
+		t.Fail()
+	}
+}
+
+func TestRead_UseNATS(t *testing.T) {
+	defaults := NewEnvBucket()
+	defaults.Setenv("faas_nats_address", "nats")
+	defaults.Setenv("faas_nats_port", "6222")
+	readConfig := types.ReadConfig{}
+
+	config := readConfig.Read(defaults)
+
+	if config.UseNATS() == false {
+		t.Log("NATS was requested in config, but not enabled.")
+		t.Fail()
+	}
+}
+
+func TestRead_UseNATSBadPort(t *testing.T) {
+
+	defaults := NewEnvBucket()
+	defaults.Setenv("faas_nats_address", "nats")
+	defaults.Setenv("faas_nats_port", "6fff")
+	readConfig := types.ReadConfig{}
+
+	config := readConfig.Read(defaults)
+
+	if config.UseNATS() == true {
+		t.Log("NATS had bad config, should not be enabled.")
+		t.Fail()
+	}
+}
+
+func TestRead_PrometheusNonDefaults(t *testing.T) {
+	defaults := NewEnvBucket()
+	defaults.Setenv("faas_prometheus_host", "prom1")
+	defaults.Setenv("faas_prometheus_port", "9999")
+	readConfig := types.ReadConfig{}
+
+	config := readConfig.Read(defaults)
+
+	if config.PrometheusHost != "prom1" {
+		t.Logf("config.PrometheusHost, want: %s, got: %s\n", "prom1", config.PrometheusHost)
+		t.Fail()
+	}
+
+	if config.PrometheusPort != 9999 {
+		t.Logf("config.PrometheusHost, want: %d, got: %d\n", 9999, config.PrometheusPort)
+		t.Fail()
+	}
+}
+
+func TestRead_PrometheusDefaults(t *testing.T) {
+	defaults := NewEnvBucket()
+
+	readConfig := types.ReadConfig{}
+
+	config := readConfig.Read(defaults)
+
+	if config.PrometheusHost != "prometheus" {
+		t.Logf("config.PrometheusHost, want: %s, got: %s\n", "prometheus", config.PrometheusHost)
+		t.Fail()
+	}
+
+	if config.PrometheusPort != 9090 {
+		t.Logf("config.PrometheusHost, want: %d, got: %d\n", 9090, config.PrometheusPort)
+		t.Fail()
+	}
+}

gateway/types/readconfig.go

@@ -48,7 +48,10 @@ func parseIntValue(val string, fallback int) int {
 
 // Read fetches config from environmental variables.
 func (ReadConfig) Read(hasEnv HasEnv) GatewayConfig {
-	cfg := GatewayConfig{}
+	cfg := GatewayConfig{
+		PrometheusHost: "prometheus",
+		PrometheusPort: 9090,
+	}
 
 	readTimeout := parseIntValue(hasEnv.Getenv("read_timeout"), 8)
 	writeTimeout := parseIntValue(hasEnv.Getenv("write_timeout"), 8)
@@ -79,6 +82,21 @@ func (ReadConfig) Read(hasEnv HasEnv) GatewayConfig {
 		}
 	}
 
+	prometheusPort := hasEnv.Getenv("faas_prometheus_port")
+	if len(prometheusPort) > 0 {
+		prometheusPortVal, err := strconv.Atoi(prometheusPort)
+		if err != nil {
+			log.Println("Invalid port for faas_prometheus_port")
+		} else {
+			cfg.PrometheusPort = prometheusPortVal
+		}
+	}
+
+	prometheusHost := hasEnv.Getenv("faas_prometheus_host")
+	if len(prometheusHost) > 0 {
+		cfg.PrometheusHost = prometheusHost
+	}
+
 	return cfg
 }
 
@@ -89,6 +107,8 @@ type GatewayConfig struct {
 	FunctionsProviderURL *url.URL
 	NATSAddress          *string
 	NATSPort             *int
+	PrometheusHost       string
+	PrometheusPort       int
 }
 
 // UseNATS Use NATSor not