Extract separate files/packages for better visibility.

docker-compose.yml

@@ -5,7 +5,7 @@ services:
             - "/var/run/docker.sock:/var/run/docker.sock"
         ports:
             - 8080:8080
-        image: alexellis2/faas-gateway:latest-dev1
+        image: alexellis2/faas-gateway:latest-dev
         networks:
             - functions
         deploy:

gateway/Dockerfile.build

@@ -10,7 +10,9 @@ RUN go get -d github.com/docker/docker/api/types \
 WORKDIR /go/src/github.com/alexellis/faas/gateway
 
 COPY metrics metrics
+COPY requests requests
 COPY server.go .
+COPY proxy.go .
 
 RUN find /go/src/github.com/alexellis/faas/gateway/
 RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o app .

gateway/metrics/metrics.go

@@ -18,3 +18,41 @@ type MetricOptions struct {
 func PrometheusHandler() http.Handler {
 	return prometheus.Handler()
 }
+
+func BuildMetricsOptions() MetricOptions {
+	GatewayRequestsTotal := prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "gateway_requests_total",
+		Help: "Total amount of HTTP requests to the gateway",
+	})
+	GatewayServerlessServedTotal := prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "gateway_serverless_invocation_total",
+		Help: "Total amount of serverless function invocations",
+	})
+	GatewayFunctions := prometheus.NewHistogram(prometheus.HistogramOpts{
+		Name: "gateway_functions",
+		Help: "Gateway functions",
+	})
+	GatewayFunctionInvocation := prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "gateway_function_invocation_total",
+			Help: "Individual function metrics",
+		},
+		[]string{"function_name"},
+	)
+
+	metricsOptions := MetricOptions{
+		GatewayRequestsTotal:         GatewayRequestsTotal,
+		GatewayServerlessServedTotal: GatewayServerlessServedTotal,
+		GatewayFunctions:             GatewayFunctions,
+		GatewayFunctionInvocation:    GatewayFunctionInvocation,
+	}
+
+	return metricsOptions
+}
+
+func RegisterMetrics(metricsOptions MetricOptions) {
+	prometheus.Register(metricsOptions.GatewayRequestsTotal)
+	prometheus.Register(metricsOptions.GatewayServerlessServedTotal)
+	prometheus.Register(metricsOptions.GatewayFunctions)
+	prometheus.Register(metricsOptions.GatewayFunctionInvocation)
+}

gateway/proxy.go

@@ -0,0 +1,132 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/alexellis/faas/gateway/metrics"
+	"github.com/alexellis/faas/gateway/requests"
+	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/filters"
+	"github.com/docker/docker/client"
+	"github.com/gorilla/mux"
+)
+
+// MakeProxy creates a proxy for HTTP web requests which can be routed to a function.
+func MakeProxy(metrics metrics.MetricOptions, wildcard bool, c *client.Client) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		metrics.GatewayRequestsTotal.Inc()
+
+		if r.Method == "POST" {
+			log.Println(r.Header)
+			header := r.Header["X-Function"]
+			log.Println(header)
+			fmt.Println(wildcard)
+
+			if wildcard == true {
+				vars := mux.Vars(r)
+				name := vars["name"]
+				fmt.Println("invoke by name")
+				lookupInvoke(w, r, metrics, name, c)
+			} else if len(header) > 0 {
+				lookupInvoke(w, r, metrics, header[0], c)
+			} else {
+				requestBody, _ := ioutil.ReadAll(r.Body)
+				alexaService := isAlexa(requestBody)
+				fmt.Println(alexaService)
+
+				if len(alexaService.Session.SessionId) > 0 &&
+					len(alexaService.Session.Application.ApplicationId) > 0 &&
+					len(alexaService.Request.Intent.Name) > 0 {
+
+					fmt.Println("Alexa SDK request found")
+					fmt.Printf("SessionId=%s, Intent=%s, AppId=%s\n", alexaService.Session.SessionId, alexaService.Request.Intent.Name, alexaService.Session.Application.ApplicationId)
+
+					invokeService(w, r, metrics, alexaService.Request.Intent.Name, requestBody)
+				} else {
+					w.WriteHeader(http.StatusBadRequest)
+					w.Write([]byte("Provide an x-function header or a valid Alexa SDK request."))
+				}
+			}
+		}
+	}
+}
+
+func isAlexa(requestBody []byte) requests.AlexaRequestBody {
+	body := requests.AlexaRequestBody{}
+	buf := bytes.NewBuffer(requestBody)
+	fmt.Println(buf)
+	str := buf.String()
+	parts := strings.Split(str, "sessionId")
+	if len(parts) > 1 {
+		json.Unmarshal(requestBody, &body)
+	}
+	return body
+}
+
+func lookupInvoke(w http.ResponseWriter, r *http.Request, metrics metrics.MetricOptions, name string, c *client.Client) {
+	exists, err := lookupSwarmService(name, c)
+	if err != nil || exists == false {
+		if err != nil {
+			log.Fatalln(err)
+		}
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte("Error resolving service."))
+	}
+	if exists == true {
+		requestBody, _ := ioutil.ReadAll(r.Body)
+		invokeService(w, r, metrics, name, requestBody)
+	}
+}
+
+func lookupSwarmService(serviceName string, c *client.Client) (bool, error) {
+	fmt.Printf("Resolving: '%s'\n", serviceName)
+	serviceFilter := filters.NewArgs()
+	serviceFilter.Add("name", serviceName)
+	services, err := c.ServiceList(context.Background(), types.ServiceListOptions{Filters: serviceFilter})
+
+	return len(services) > 0, err
+}
+
+func invokeService(w http.ResponseWriter, r *http.Request, metrics metrics.MetricOptions, service string, requestBody []byte) {
+	metrics.GatewayFunctionInvocation.WithLabelValues(service).Add(1)
+
+	stamp := strconv.FormatInt(time.Now().Unix(), 10)
+
+	start := time.Now()
+	buf := bytes.NewBuffer(requestBody)
+	url := "http://" + service + ":" + strconv.Itoa(8080) + "/"
+	fmt.Printf("[%s] Forwarding request to: %s\n", stamp, url)
+	response, err := http.Post(url, "text/plain", buf)
+	if err != nil {
+		log.Println(err)
+		w.WriteHeader(500)
+		buf := bytes.NewBufferString("Can't reach service: " + service)
+		w.Write(buf.Bytes())
+		return
+	}
+
+	responseBody, readErr := ioutil.ReadAll(response.Body)
+	if readErr != nil {
+		fmt.Println(readErr)
+		w.WriteHeader(500)
+		buf := bytes.NewBufferString("Error reading response from service: " + service)
+		w.Write(buf.Bytes())
+		return
+	}
+
+	w.WriteHeader(http.StatusOK)
+	w.Write(responseBody)
+	seconds := time.Since(start).Seconds()
+	fmt.Printf("[%s] took %f seconds\n", stamp, seconds)
+	metrics.GatewayServerlessServedTotal.Inc()
+	metrics.GatewayFunctions.Observe(seconds)
+}

gateway/requests/requests.go

@@ -0,0 +1,23 @@
+package requests
+
+type AlexaSessionApplication struct {
+	ApplicationId string `json:"applicationId"`
+}
+
+type AlexaSession struct {
+	SessionId   string                  `json:"sessionId"`
+	Application AlexaSessionApplication `json:"application"`
+}
+
+type AlexaIntent struct {
+	Name string `json:"name"`
+}
+
+type AlexaRequest struct {
+	Intent AlexaIntent `json:"intent"`
+}
+
+type AlexaRequestBody struct {
+	Session AlexaSession `json:"session"`
+	Request AlexaRequest `json:"request"`
+}

gateway/server.go

@@ -1,159 +1,16 @@
 package main
 
 import (
-	"bytes"
-	"context"
 	"fmt"
 	"log"
 	"net/http"
-	"strconv"
-	"strings"
 	"time"
 
-	"io/ioutil"
-
-	"encoding/json"
-
 	"github.com/alexellis/faas/gateway/metrics"
-	"github.com/docker/docker/api/types"
-	"github.com/docker/docker/api/types/filters"
 	"github.com/docker/docker/client"
 	"github.com/gorilla/mux"
-	"github.com/prometheus/client_golang/prometheus"
 )
 
-type AlexaSessionApplication struct {
-	ApplicationId string `json:"applicationId"`
-}
-
-type AlexaSession struct {
-	SessionId   string                  `json:"sessionId"`
-	Application AlexaSessionApplication `json:"application"`
-}
-
-type AlexaIntent struct {
-	Name string `json:"name"`
-}
-
-type AlexaRequest struct {
-	Intent AlexaIntent `json:"intent"`
-}
-
-type AlexaRequestBody struct {
-	Session AlexaSession `json:"session"`
-	Request AlexaRequest `json:"request"`
-}
-
-func lookupSwarmService(serviceName string, c *client.Client) (bool, error) {
-	fmt.Printf("Resolving: '%s'\n", serviceName)
-	serviceFilter := filters.NewArgs()
-	serviceFilter.Add("name", serviceName)
-	services, err := c.ServiceList(context.Background(), types.ServiceListOptions{Filters: serviceFilter})
-
-	return len(services) > 0, err
-}
-
-func isAlexa(requestBody []byte) AlexaRequestBody {
-	body := AlexaRequestBody{}
-	buf := bytes.NewBuffer(requestBody)
-	fmt.Println(buf)
-	str := buf.String()
-	parts := strings.Split(str, "sessionId")
-	if len(parts) > 1 {
-		json.Unmarshal(requestBody, &body)
-	}
-	return body
-}
-
-func invokeService(w http.ResponseWriter, r *http.Request, metrics metrics.MetricOptions, service string, requestBody []byte) {
-	metrics.GatewayFunctionInvocation.WithLabelValues(service).Add(1)
-
-	stamp := strconv.FormatInt(time.Now().Unix(), 10)
-
-	start := time.Now()
-	buf := bytes.NewBuffer(requestBody)
-	url := "http://" + service + ":" + strconv.Itoa(8080) + "/"
-	fmt.Printf("[%s] Forwarding request to: %s\n", stamp, url)
-	response, err := http.Post(url, "text/plain", buf)
-	if err != nil {
-		log.Println(err)
-		w.WriteHeader(500)
-		buf := bytes.NewBufferString("Can't reach service: " + service)
-		w.Write(buf.Bytes())
-		return
-	}
-
-	responseBody, readErr := ioutil.ReadAll(response.Body)
-	if readErr != nil {
-		fmt.Println(readErr)
-		w.WriteHeader(500)
-		buf := bytes.NewBufferString("Error reading response from service: " + service)
-		w.Write(buf.Bytes())
-		return
-	}
-
-	w.WriteHeader(http.StatusOK)
-	w.Write(responseBody)
-	seconds := time.Since(start).Seconds()
-	fmt.Printf("[%s] took %f seconds\n", stamp, seconds)
-	metrics.GatewayServerlessServedTotal.Inc()
-	metrics.GatewayFunctions.Observe(seconds)
-}
-
-func lookupInvoke(w http.ResponseWriter, r *http.Request, metrics metrics.MetricOptions, name string, c *client.Client) {
-	exists, err := lookupSwarmService(name, c)
-	if err != nil || exists == false {
-		if err != nil {
-			log.Fatalln(err)
-		}
-		w.WriteHeader(http.StatusInternalServerError)
-		w.Write([]byte("Error resolving service."))
-	}
-	if exists == true {
-		requestBody, _ := ioutil.ReadAll(r.Body)
-		invokeService(w, r, metrics, name, requestBody)
-	}
-}
-
-func makeProxy(metrics metrics.MetricOptions, wildcard bool, c *client.Client) http.HandlerFunc {
-	return func(w http.ResponseWriter, r *http.Request) {
-		metrics.GatewayRequestsTotal.Inc()
-
-		if r.Method == "POST" {
-			log.Println(r.Header)
-			header := r.Header["X-Function"]
-			log.Println(header)
-			fmt.Println(wildcard)
-
-			if wildcard == true {
-				vars := mux.Vars(r)
-				name := vars["name"]
-				fmt.Println("invoke by name")
-				lookupInvoke(w, r, metrics, name, c)
-			} else if len(header) > 0 {
-				lookupInvoke(w, r, metrics, header[0], c)
-			} else {
-				requestBody, _ := ioutil.ReadAll(r.Body)
-				alexaService := isAlexa(requestBody)
-				fmt.Println(alexaService)
-
-				if len(alexaService.Session.SessionId) > 0 &&
-					len(alexaService.Session.Application.ApplicationId) > 0 &&
-					len(alexaService.Request.Intent.Name) > 0 {
-
-					fmt.Println("Alexa SDK request found")
-					fmt.Printf("SessionId=%s, Intent=%s, AppId=%s\n", alexaService.Session.SessionId, alexaService.Request.Intent.Name, alexaService.Session.Application.ApplicationId)
-
-					invokeService(w, r, metrics, alexaService.Request.Intent.Name, requestBody)
-				} else {
-					w.WriteHeader(http.StatusBadRequest)
-					w.Write([]byte("Provide an x-function header or a valid Alexa SDK request."))
-				}
-			}
-		}
-	}
-}
-
 func makeAlertHandler(c *client.Client) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		fmt.Println(c)
@@ -164,51 +21,20 @@ func makeAlertHandler(c *client.Client) http.HandlerFunc {
 }
 
 func main() {
-	GatewayRequestsTotal := prometheus.NewCounter(prometheus.CounterOpts{
+	var dockerClient *client.Client
-		Name: "gateway_requests_total",
-		Help: "Total amount of HTTP requests to the gateway",
-	})
-	GatewayServerlessServedTotal := prometheus.NewCounter(prometheus.CounterOpts{
-		Name: "gateway_serverless_invocation_total",
-		Help: "Total amount of serverless function invocations",
-	})
-	GatewayFunctions := prometheus.NewHistogram(prometheus.HistogramOpts{
-		Name: "gateway_functions",
-		Help: "Gateway functions",
-	})
-	GatewayFunctionInvocation := prometheus.NewCounterVec(
-		prometheus.CounterOpts{
-			Name: "gateway_function_invocation_total",
-			Help: "Individual function metrics",
-		},
-		[]string{"function_name"},
-	)
-
-	prometheus.Register(GatewayRequestsTotal)
-	prometheus.Register(GatewayServerlessServedTotal)
-	prometheus.Register(GatewayFunctions)
-	prometheus.Register(GatewayFunctionInvocation)
-
-	metricsOptions := metrics.MetricOptions{
-		GatewayRequestsTotal:         GatewayRequestsTotal,
-		GatewayServerlessServedTotal: GatewayServerlessServedTotal,
-		GatewayFunctions:             GatewayFunctions,
-		GatewayFunctionInvocation:    GatewayFunctionInvocation,
-	}
-
-	var c *client.Client
 	var err error
-	c, err = client.NewEnvClient()
+	dockerClient, err = client.NewEnvClient()
 	if err != nil {
 		log.Fatal("Error with Docker client.")
 	}
 
+	metricsOptions := metrics.BuildMetricsOptions()
+	metrics.RegisterMetrics(metricsOptions)
+
 	r := mux.NewRouter()
-	r.HandleFunc("/function/{name:[a-zA-Z_]+}", makeProxy(metricsOptions, true, c))
+	r.HandleFunc("/function/{name:[a-zA-Z_]+}", MakeProxy(metricsOptions, true, dockerClient))
-
+	r.HandleFunc("/system/alert", makeAlertHandler(dockerClient))
-	r.HandleFunc("/system/alert", makeAlertHandler(c))
+	r.HandleFunc("/", MakeProxy(metricsOptions, false, dockerClient))
-
-	r.HandleFunc("/", makeProxy(metricsOptions, false, c))
 
 	metricsHandler := metrics.PrometheusHandler()
 	r.Handle("/metrics", metricsHandler)

prometheus/alert.rules

@@ -4,12 +4,12 @@ ALERT service_down
 ALERT APIHighInvocationRate
   IF rate ( gateway_function_invocation_total [10s] ) > 5
   FOR 30s
-  ANNOTATIONS {
-    summary = "High invocation total on {{ $labels.instance }}",
-    description =  "High invocation total on {{ $labels.instance }}",
-  }
   LABELS {
     service = "gateway",
     severity = "major",
-    value = "{{$value}}",
+    value = "{{$value}}"
   }
+  ANNOTATIONS {
+    summary = "High invocation total on {{ $labels.instance }}",
+    description =  "High invocation total on {{ $labels.instance }}"
+  }