Expose number of failed hook executions

cmd/tusd/cli/hooks.go

@@ -37,6 +37,14 @@ func (store hookDataStore) NewUpload(info tusd.FileInfo) (id string, err error)
 	return store.DataStore.NewUpload(info)
 }
 
+func SetupHookMetrics() {
+	MetricsHookErrorsTotal.WithLabelValues(string(HookPostFinish)).Add(0)
+	MetricsHookErrorsTotal.WithLabelValues(string(HookPostTerminate)).Add(0)
+	MetricsHookErrorsTotal.WithLabelValues(string(HookPostReceive)).Add(0)
+	MetricsHookErrorsTotal.WithLabelValues(string(HookPostCreate)).Add(0)
+	MetricsHookErrorsTotal.WithLabelValues(string(HookPreCreate)).Add(0)
+}
+
 func SetupPreHooks(composer *tusd.StoreComposer) {
 	composer.UseCore(hookDataStore{
 		DataStore: composer.Core,
@@ -94,6 +102,7 @@ func invokeHookSync(typ HookType, info tusd.FileInfo, captureOutput bool) ([]byt
 
 	if err != nil {
 		logEv(stderr, "HookInvocationError", "type", string(typ), "id", info.ID, "error", err.Error())
+		MetricsHookErrorsTotal.WithLabelValues(string(typ)).Add(1)
 	} else {
 		logEv(stdout, "HookInvocationFinish", "type", string(typ), "id", info.ID)
 	}

cmd/tusd/cli/metrics.go

@@ -14,8 +14,17 @@ var MetricsOpenConnections = prometheus.NewGauge(prometheus.GaugeOpts{
 	Help: "Current number of open connections.",
 })
 
+var MetricsHookErrorsTotal = prometheus.NewCounterVec(
+	prometheus.CounterOpts{
+		Name: "tusd_hook_errors_total",
+		Help: "Total number of execution errors per hook type.",
+	},
+	[]string{"hooktype"},
+)
+
 func SetupMetrics(handler *tusd.Handler) {
 	prometheus.MustRegister(MetricsOpenConnections)
+	prometheus.MustRegister(MetricsHookErrorsTotal)
 	prometheus.MustRegister(prometheuscollector.New(handler.Metrics))
 
 	stdout.Printf("Using %s as the metrics path.\n", Flags.MetricsPath)

cmd/tusd/cli/serve.go

@@ -34,6 +34,7 @@ func Serve() {
 
 	if Flags.ExposeMetrics {
 		SetupMetrics(handler)
+		SetupHookMetrics()
 	}
 
 	stdout.Printf(Composer.Capabilities())