From 4a8159ef828f68ee359e185622d9232fb6ca3a6f Mon Sep 17 00:00:00 2001
From: Michael Panzlaff <michael.panzlaff@fau.de>
Date: Tue, 24 Feb 2026 17:30:52 +0100
Subject: [PATCH] Fix possibly missing metrics in nfs collector

We should not rely on the availablity of certain nfs metrics at just the
collector start time. Allow new metrics to come in at any point.
---
 collectors/nfsMetric.go | 95 ++++++++++++++++++-----------------------
 1 file changed, 41 insertions(+), 54 deletions(-)

diff --git a/collectors/nfsMetric.go b/collectors/nfsMetric.go
index fb48b9d..38965ec 100644
--- a/collectors/nfsMetric.go
+++ b/collectors/nfsMetric.go
@@ -44,38 +44,6 @@ type nfsCollector struct {
 	data map[string]NfsCollectorData
 }
 
-func (m *nfsCollector) initStats() error {
-	cmd := exec.Command(m.config.Nfsstats, `-l`, `--all`)
-
-	// Wait for cmd end
-	if err := cmd.Wait(); err != nil {
-		return fmt.Errorf("%s initStats(): %w", m.name, err)
-	}
-
-	buffer, err := cmd.Output()
-	if err == nil {
-		for line := range strings.Lines(string(buffer)) {
-			lf := strings.Fields(line)
-			if len(lf) != 5 {
-				continue
-			}
-			if lf[1] == m.version {
-				name := strings.Trim(lf[3], ":")
-				if _, exist := m.data[name]; !exist {
-					value, err := strconv.ParseInt(lf[4], 0, 64)
-					if err == nil {
-						x := m.data[name]
-						x.current = value
-						x.last = value
-						m.data[name] = x
-					}
-				}
-			}
-		}
-	}
-	return err
-}
-
 func (m *nfsCollector) updateStats() error {
 	cmd := exec.Command(m.config.Nfsstats, `-l`, `--all`)
 
@@ -85,27 +53,42 @@ func (m *nfsCollector) updateStats() error {
 	}
 
 	buffer, err := cmd.Output()
-	if err == nil {
-		for line := range strings.Lines(string(buffer)) {
-			lf := strings.Fields(line)
-			if len(lf) != 5 {
-				continue
-			}
-			if lf[1] == m.version {
-				name := strings.Trim(lf[3], ":")
-				if _, exist := m.data[name]; exist {
-					value, err := strconv.ParseInt(lf[4], 0, 64)
-					if err == nil {
-						x := m.data[name]
-						x.last = x.current
-						x.current = value
-						m.data[name] = x
-					}
-				}
-			}
+	if err != nil {
+		return err
+	}
+
+	for name, data := range m.data {
+		m.data[name] = NfsCollectorData{
+			last:    data.current,
+			current: -1,
 		}
 	}
-	return err
+
+	for line := range strings.Lines(string(buffer)) {
+		lf := strings.Fields(line)
+		if len(lf) != 5 {
+			continue
+		}
+		if lf[1] != m.version {
+			continue
+		}
+		name := strings.Trim(lf[3], ":")
+		value, err := strconv.ParseInt(lf[4], 0, 64)
+		if err != nil {
+			return err
+		}
+
+		collectorData, exist := m.data[name]
+		collectorData.current = value
+
+		if !exist {
+			collectorData.last = -1
+		}
+
+		m.data[name] = collectorData
+	}
+
+	return nil
 }
 
 func (m *nfsCollector) MainInit(config json.RawMessage) error {
@@ -130,7 +113,7 @@ func (m *nfsCollector) MainInit(config json.RawMessage) error {
 		return fmt.Errorf("%s Init(): Failed to find nfsstat binary '%s': %w", m.name, m.config.Nfsstats, err)
 	}
 	m.data = make(map[string]NfsCollectorData)
-	if err := m.initStats(); err != nil {
+	if err := m.updateStats(); err != nil {
 		return fmt.Errorf("%s Init(): %w", m.name, err)
 	}
 	m.init = true
@@ -165,8 +148,12 @@ func (m *nfsCollector) Read(interval time.Duration, output chan lp.CCMessage) {
 		if slices.Contains(m.config.ExcludeMetrics, name) {
 			continue
 		}
-		value := data.current - data.last
-		y, err := lp.NewMessage(fmt.Sprintf("%s_%s", prefix, name), m.tags, m.meta, map[string]any{"value": value}, timestamp)
+
+		valueMap := make(map[string]any)
+		if data.current >= 0 && data.last >= 0 {
+			valueMap["value"] = data.current - data.last
+		}
+		y, err := lp.NewMessage(fmt.Sprintf("%s_%s", prefix, name), m.tags, m.meta, valueMap, timestamp)
 		if err == nil {
 			y.AddMeta("version", m.version)
 			output <- y