Make sure we only return one metric per mounted fs

collector/filesystem_bsd.go

@@ -66,15 +66,18 @@ func (c *filesystemCollector) GetStats() (stats []filesystemStats, err error) {
 			ro = 1
 		}
 
-		labelValues := []string{device, mountpoint, fstype}
 		stats = append(stats, filesystemStats{
-			labelValues: labelValues,
-			size:        float64(mnt[i].f_blocks) * float64(mnt[i].f_bsize),
-			free:        float64(mnt[i].f_bfree) * float64(mnt[i].f_bsize),
-			avail:       float64(mnt[i].f_bavail) * float64(mnt[i].f_bsize),
-			files:       float64(mnt[i].f_files),
-			filesFree:   float64(mnt[i].f_ffree),
-			ro:          ro,
+			labels: filesystemLabels{
+				device:     device,
+				mountPoint: mountpoint,
+				fsType:     fstype,
+			},
+			size:      float64(mnt[i].f_blocks) * float64(mnt[i].f_bsize),
+			free:      float64(mnt[i].f_bfree) * float64(mnt[i].f_bsize),
+			avail:     float64(mnt[i].f_bavail) * float64(mnt[i].f_bsize),
+			files:     float64(mnt[i].f_files),
+			filesFree: float64(mnt[i].f_ffree),
+			ro:        ro,
 		})
 	}
 	return stats, nil

collector/filesystem_common.go

@@ -51,8 +51,12 @@ type filesystemCollector struct {
 	devErrors *prometheus.CounterVec
 }
 
+type filesystemLabels struct {
+	device, mountPoint, fsType string
+}
+
 type filesystemStats struct {
-	labelValues                             []string
+	labels                                  filesystemLabels
 	size, free, avail, files, filesFree, ro float64
 }
 
@@ -126,30 +130,37 @@ func (c *filesystemCollector) Update(ch chan<- prometheus.Metric) (err error) {
 	if err != nil {
 		return err
 	}
+	// Make sure we expose a metric once, even if there are multiple mounts
+	seen := map[filesystemLabels]bool{}
 	for _, s := range stats {
+		if seen[s.labels] {
+			continue
+		}
+		seen[s.labels] = true
+
 		ch <- prometheus.MustNewConstMetric(
 			c.sizeDesc, prometheus.GaugeValue,
-			s.size, s.labelValues...,
+			s.size, s.labels.device, s.labels.mountPoint, s.labels.fsType,
 		)
 		ch <- prometheus.MustNewConstMetric(
 			c.freeDesc, prometheus.GaugeValue,
-			s.free, s.labelValues...,
+			s.free, s.labels.device, s.labels.mountPoint, s.labels.fsType,
 		)
 		ch <- prometheus.MustNewConstMetric(
 			c.availDesc, prometheus.GaugeValue,
-			s.avail, s.labelValues...,
+			s.avail, s.labels.device, s.labels.mountPoint, s.labels.fsType,
 		)
 		ch <- prometheus.MustNewConstMetric(
 			c.filesDesc, prometheus.GaugeValue,
-			s.files, s.labelValues...,
+			s.files, s.labels.device, s.labels.mountPoint, s.labels.fsType,
 		)
 		ch <- prometheus.MustNewConstMetric(
 			c.filesFreeDesc, prometheus.GaugeValue,
-			s.filesFree, s.labelValues...,
+			s.filesFree, s.labels.device, s.labels.mountPoint, s.labels.fsType,
 		)
 		ch <- prometheus.MustNewConstMetric(
 			c.roDesc, prometheus.GaugeValue,
-			s.ro, s.labelValues...,
+			s.ro, s.labels.device, s.labels.mountPoint, s.labels.fsType,
 		)
 	}
 	c.devErrors.Collect(ch)

collector/filesystem_freebsd.go

@@ -73,15 +73,18 @@ func (c *filesystemCollector) GetStats() (stats []filesystemStats, err error) {
 			ro = 1
 		}
 
-		labelValues := []string{device, mountpoint, fstype}
 		stats = append(stats, filesystemStats{
-			labelValues: labelValues,
-			size:        float64(fs.Blocks) * float64(fs.Bsize),
-			free:        float64(fs.Bfree) * float64(fs.Bsize),
-			avail:       float64(fs.Bavail) * float64(fs.Bsize),
-			files:       float64(fs.Files),
-			filesFree:   float64(fs.Ffree),
-			ro:          ro,
+			labels: filesystemLabels{
+				device:     device,
+				mountPoint: mountpoint,
+				fsType:     fstype,
+			},
+			size:      float64(fs.Blocks) * float64(fs.Bsize),
+			free:      float64(fs.Bfree) * float64(fs.Bsize),
+			avail:     float64(fs.Bavail) * float64(fs.Bsize),
+			files:     float64(fs.Files),
+			filesFree: float64(fs.Ffree),
+			ro:        ro,
 		})
 	}
 	return stats, nil

collector/filesystem_linux.go

@@ -30,35 +30,29 @@ const (
 	ST_RDONLY             = 0x1
 )
 
-type filesystemDetails struct {
-	device     string
-	mountPoint string
-	fsType     string
-}
-
 // Expose filesystem fullness.
 func (c *filesystemCollector) GetStats() (stats []filesystemStats, err error) {
-	mpds, err := mountPointDetails()
+	mps, err := mountPointDetails()
 	if err != nil {
 		return nil, err
 	}
 	stats = []filesystemStats{}
-	for _, mpd := range mpds {
-		if c.ignoredMountPointsPattern.MatchString(mpd.mountPoint) {
-			log.Debugf("Ignoring mount point: %s", mpd.mountPoint)
+	for _, labels := range mps {
+		if c.ignoredMountPointsPattern.MatchString(labels.mountPoint) {
+			log.Debugf("Ignoring mount point: %s", labels.mountPoint)
 			continue
 		}
-		if c.ignoredFSTypesPattern.MatchString(mpd.fsType) {
-			log.Debugf("Ignoring fs type: %s", mpd.fsType)
+		if c.ignoredFSTypesPattern.MatchString(labels.fsType) {
+			log.Debugf("Ignoring fs type: %s", labels.fsType)
 			continue
 		}
-		labelValues := []string{mpd.device, mpd.mountPoint, mpd.fsType}
+		labelValues := []string{labels.device, labels.mountPoint, labels.fsType}
 		buf := new(syscall.Statfs_t)
-		err := syscall.Statfs(mpd.mountPoint, buf)
+		err := syscall.Statfs(labels.mountPoint, buf)
 		if err != nil {
 			c.devErrors.WithLabelValues(labelValues...).Inc()
 			log.Debugf("Statfs on %s returned %s",
-				mpd.mountPoint, err)
+				labels.mountPoint, err)
 			continue
 		}
 
@@ -68,31 +62,31 @@ func (c *filesystemCollector) GetStats() (stats []filesystemStats, err error) {
 		}
 
 		stats = append(stats, filesystemStats{
-			labelValues: labelValues,
-			size:        float64(buf.Blocks) * float64(buf.Bsize),
-			free:        float64(buf.Bfree) * float64(buf.Bsize),
-			avail:       float64(buf.Bavail) * float64(buf.Bsize),
-			files:       float64(buf.Files),
-			filesFree:   float64(buf.Ffree),
-			ro:          ro,
+			labels:    labels,
+			size:      float64(buf.Blocks) * float64(buf.Bsize),
+			free:      float64(buf.Bfree) * float64(buf.Bsize),
+			avail:     float64(buf.Bavail) * float64(buf.Bsize),
+			files:     float64(buf.Files),
+			filesFree: float64(buf.Ffree),
+			ro:        ro,
 		})
 	}
 	return stats, nil
 }
 
-func mountPointDetails() ([]filesystemDetails, error) {
+func mountPointDetails() ([]filesystemLabels, error) {
 	file, err := os.Open(procFilePath("mounts"))
 	if err != nil {
 		return nil, err
 	}
 	defer file.Close()
 
-	filesystems := []filesystemDetails{}
+	filesystems := []filesystemLabels{}
 
 	scanner := bufio.NewScanner(file)
 	for scanner.Scan() {
 		parts := strings.Fields(scanner.Text())
-		filesystems = append(filesystems, filesystemDetails{parts[0], parts[1], parts[2]})
+		filesystems = append(filesystems, filesystemLabels{parts[0], parts[1], parts[2]})
 	}
-	return filesystems, nil
+	return filesystems, scanner.Err()
 }