Add instrumentation

browser.go

@@ -2,7 +2,9 @@ package reportscollector
 
 import (
 	"encoding/json"
+	"net"
 	"net/http"
+	"net/url"
 	"time"
 )
 
@@ -41,7 +43,18 @@ func (h *ReportHandler) eventFromReport(report *report) Event {
 	e.Set("type", report.Type)
 	e.Set("event_timestamp", ts)
 	e.Set("url", report.URL)
+	e.Set("domain", domainFromURL(report.URL))
 	e.Set("user_agent", report.UserAgent)
 	e.Set("body", report.Body)
 	return e
 }
+
+func domainFromURL(u string) string {
+	if uri, err := url.Parse(u); err == nil {
+		if host, _, err := net.SplitHostPort(uri.Host); err == nil {
+			return host
+		}
+		return uri.Host
+	}
+	return ""
+}

cmd/reports-collector/main.go

 package main
 
 import (
+	"context"
 	"flag"
 	"log"
 	"net/http"
 	"os"
+	"os/signal"
+	"syscall"
 	"time"
 
 	rc "git.autistici.org/ai3/tools/reports-collector"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
 var (
 	addr = flag.String("addr", fromEnv("ADDR", ":4890"), "address to listen on")
+
+	gracefulShutdownTimeout = 5 * time.Second
 )
 
 func fromEnv(name, deflt string) string {
@@ -34,6 +40,7 @@ func main() {
 	// Create the http.Server.
 	mux := http.NewServeMux()
 	mux.Handle("/ingest/v1", collector)
+	mux.Handle("/metrics", promhttp.Handler())
 	server := &http.Server{
 		Addr:         *addr,
 		Handler:      mux,
@@ -42,8 +49,30 @@ func main() {
 		WriteTimeout: 10 * time.Second,
 	}
 
+	done := make(chan struct{})
+	sigCh := make(chan os.Signal, 1)
+	go func() {
+		<-sigCh
+		log.Printf("terminating")
+		// Gracefully terminate, then shut down remaining
+		// clients.
+		ctx, cancel := context.WithTimeout(
+			context.Background(), gracefulShutdownTimeout)
+		defer cancel()
+		if err := server.Shutdown(ctx); err == context.Canceled {
+			if err := server.Close(); err != nil {
+				log.Printf("error terminating server: %v", err)
+			}
+		}
+		close(done)
+	}()
+
+	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
+
 	err := server.ListenAndServe()
-	if err != nil {
-		log.Fatalf("error: %v", err)
+	if err != nil && err != http.ErrServerClosed {
+		log.Fatalf("server error: %v", err)
 	}
+
+	<-done
 }

collector.go

@@ -6,6 +6,8 @@ import (
 	"log"
 	"mime"
 	"net/http"
+
+	"github.com/prometheus/client_golang/prometheus"
 )
 
 var ErrNoMatch = errors.New("no match")
@@ -69,5 +71,17 @@ hloop:
 	for _, e := range events {
 		e.Set("ip", ip)
 		c.sink.Send(e)
+		reportsByType.WithLabelValues(
+			e.GetString("type"), e.GetString("domain")).Inc()
 	}
 }
+
+var (
+	reportsByType = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "reports_total",
+			Help: "Number of reports by type.",
+		},
+		[]string{"type", "domain"},
+	)
+)

event.go

@@ -5,3 +5,7 @@ type Event map[string]interface{}
 func (e Event) Set(key string, value interface{}) {
 	e[key] = value
 }
+
+func (e Event) GetString(key string) string {
+	return e[key].(string)
+}

go.mod

 module git.autistici.org/ai3/tools/reports-collector
+
+require (
+	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
+	github.com/prometheus/client_golang v1.8.0
+	gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 // indirect
+)