From 5494c222d8022aea586f3713a8ba0edf0b8d099e Mon Sep 17 00:00:00 2001
From: Nick Loginov <nick.loginov@booking.com>
Date: Thu, 26 Nov 2020 09:23:48 +0100
Subject: [PATCH] make bpfink more fail-tolerant during startup & runtime (#46)

1. Bad consumer initialization during startup does not lead to crash anymore
2. BPF kernel metrics file bad closing doesn't lead to crash anymore
3. Links to socket files are not monitored anymore
4. Removed some unreachable/redundant code

Co-authored-by: Nick Loginov <>
---
 cmd/main.go     | 11 ++++++-----
 pkg/graphite.go |  7 +++----
 pkg/watcher.go  |  4 ----
 3 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/cmd/main.go b/cmd/main.go
index 42b7a97..b81e6eb 100644
--- a/cmd/main.go
+++ b/cmd/main.go
@@ -327,6 +327,10 @@ func (c Configuration) resolvePath(pathFull string) (string, os.FileInfo) {
 			}
 			return "", nil
 		}
+		if fileInfo.Mode()&os.ModeSocket != 0 {
+			return "", nil
+		}
+
 		fi = fileInfo
 		pathFull = linkPath
 	}
@@ -409,7 +413,7 @@ func (c Configuration) watcher() (*pkg.Watcher, error) {
 
 	for _, consumer := range consumers {
 		if err := consumer.Init(); err != nil {
-			logger.Fatal().Err(err).Msg("failed to init consumer")
+			logger.Error().Err(err).Msg("failed to init consumer")
 		}
 	}
 	return pkg.NewWatcher(func(w *pkg.Watcher) {
@@ -472,10 +476,7 @@ func run() error {
 	metrics.RecordByInstalledHost()
 	// send version metric
 	metrics.RecordVersion(Version)
-	err = metrics.RecordBPFMetrics()
-	if err != nil {
-		logger.Fatal().Err(err).Msg("error starting bpf metrics")
-	}
+	metrics.RecordBPFMetrics()
 	key := make([]byte, keySize)
 	if config.Keyfile == "" {
 		if _, err := io.ReadFull(rand.Reader, key); err != nil {
diff --git a/pkg/graphite.go b/pkg/graphite.go
index e57736f..c281bb6 100644
--- a/pkg/graphite.go
+++ b/pkg/graphite.go
@@ -119,7 +119,7 @@ func (m *Metrics) RecordByInstalledHost() {
 }
 
 // RecordBPFMetrics send metrics for BPF hits and misses per probe
-func (m *Metrics) RecordBPFMetrics() error {
+func (m *Metrics) RecordBPFMetrics() {
 	go func() {
 		for range time.Tick(m.MetricsInterval) {
 			BPFMetrics, err := m.fetchBPFMetrics()
@@ -138,7 +138,6 @@ func (m *Metrics) RecordBPFMetrics() error {
 			}
 		}
 	}()
-	return nil
 }
 
 func (m *Metrics) fetchBPFMetrics() (map[string]bpfMetrics, error) {
@@ -150,7 +149,7 @@ func (m *Metrics) fetchBPFMetrics() (map[string]bpfMetrics, error) {
 	}
 	defer func() {
 		if err := file.Close(); err != nil {
-			log.Fatal(err)
+			log.Print(err)
 		}
 	}()
 
@@ -209,7 +208,7 @@ func (m *Metrics) fetchBPFMetrics() (map[string]bpfMetrics, error) {
 	}
 
 	if err := scanner.Err(); err != nil {
-		log.Fatal(err)
+		log.Print(err)
 	}
 	return BPFMetrics, nil
 }
diff --git a/pkg/watcher.go b/pkg/watcher.go
index a9af074..7556e4a 100644
--- a/pkg/watcher.go
+++ b/pkg/watcher.go
@@ -209,11 +209,7 @@ func (w *Watcher) removeInode(key uint64) {
 func (w *Watcher) Start() error {
 	defer func() {
 		if i := recover(); i != nil {
-			w.Fatal().Msgf("Panic Caught")
 			w.Fatal().Msgf("Caught panic: %v", i)
-			if err := w.Start(); err != nil {
-				w.Error().Err(err)
-			}
 		}
 	}()
 	w.Debug().Msgf("consumer Count: %v", len(w.Consumers))