Fix scanner usage without error handling

collector/diskstats_linux.go

@@ -239,5 +239,5 @@ func parseDiskStats(r io.Reader) (map[string]map[int]string, error) {
 		diskStats[dev][12] = bytesWritten
 	}
 
-	return diskStats, nil
+	return diskStats, scanner.Err()
 }

collector/filefd_linux.go

@@ -16,12 +16,11 @@
 package collector
 
 import (
-	"bufio"
+	"bytes"
 	"fmt"
-	"io"
+	"io/ioutil"
 	"os"
 	"strconv"
-	"strings"
 
 	"github.com/prometheus/client_golang/prometheus"
 )
@@ -41,8 +40,8 @@ func NewFileFDStatCollector() (Collector, error) {
 	return &fileFDStatCollector{}, nil
 }
 
-func (c *fileFDStatCollector) Update(ch chan<- prometheus.Metric) (err error) {
-	fileFDStat, err := getFileFDStats(procFilePath("sys/fs/file-nr"))
+func (c *fileFDStatCollector) Update(ch chan<- prometheus.Metric) error {
+	fileFDStat, err := parseFileFDStats(procFilePath("sys/fs/file-nr"))
 	if err != nil {
 		return fmt.Errorf("couldn't get file-nr: %s", err)
 	}
@@ -63,25 +62,27 @@ func (c *fileFDStatCollector) Update(ch chan<- prometheus.Metric) (err error) {
 	return nil
 }
 
-func getFileFDStats(fileName string) (map[string]string, error) {
-	file, err := os.Open(fileName)
+func parseFileFDStats(filename string) (map[string]string, error) {
+	file, err := os.Open(filename)
 	if err != nil {
 		return nil, err
 	}
 	defer file.Close()
-	return parseFileFDStats(file, fileName)
+
+	content, err := ioutil.ReadAll(file)
+	if err != nil {
+		return nil, err
+	}
+	parts := bytes.Split(bytes.TrimSpace(content), []byte("\u0009"))
+	if len(parts) < 3 {
+		return nil, fmt.Errorf("unexpected number of file stats in %q", filename)
 	}
 
-func parseFileFDStats(r io.Reader, fileName string) (map[string]string, error) {
-	var scanner = bufio.NewScanner(r)
-	scanner.Scan()
-	// The file-nr proc file is separated by tabs, not spaces.
-	line := strings.Split(scanner.Text(), "\u0009")
 	var fileFDStat = map[string]string{}
 	// The file-nr proc is only 1 line with 3 values.
-	fileFDStat["allocated"] = line[0]
+	fileFDStat["allocated"] = string(parts[0])
 	// The second value is skipped as it will always be zero in linux 2.6.
-	fileFDStat["maximum"] = line[2]
+	fileFDStat["maximum"] = string(parts[2])
 
 	return fileFDStat, nil
 }

collector/filefd_linux_test.go

@@ -13,28 +13,19 @@
 
 package collector
 
-import (
-	"os"
-	"testing"
-)
+import "testing"
 
 func TestFileFDStats(t *testing.T) {
-	file, err := os.Open("fixtures/proc/sys/fs/file-nr")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer file.Close()
-
-	fileFDStats, err := parseFileFDStats(file, fileName)
+	fileFDStats, err := parseFileFDStats("fixtures/proc/sys/fs/file-nr")
 	if err != nil {
 		t.Fatal(err)
 	}
 
 	if want, got := "1024", fileFDStats["allocated"]; want != got {
-		t.Errorf("want filefd allocated %s, got %s", want, got)
+		t.Errorf("want filefd allocated %q, got %q", want, got)
 	}
 
 	if want, got := "1631329", fileFDStats["maximum"]; want != got {
-		t.Errorf("want filefd maximum %s, got %s", want, got)
+		t.Errorf("want filefd maximum %q, got %q", want, got)
 	}
 }

collector/interrupts_linux.go

@@ -94,5 +94,5 @@ func parseInterrupts(r io.Reader) (map[string]interrupt, error) {
 		interrupts[intName] = intr
 	}
 
-	return interrupts, nil
+	return interrupts, scanner.Err()
 }

collector/megacli.go

@@ -122,7 +122,7 @@ func parseMegaCliDisks(r io.Reader) (map[int]map[int]map[string]string, error) {
 		}
 	}
 
-	return stats, nil
+	return stats, scanner.Err()
 }
 
 func parseMegaCliAdapter(r io.Reader) (map[string]map[string]string, error) {
@@ -155,7 +155,7 @@ func parseMegaCliAdapter(r io.Reader) (map[string]map[string]string, error) {
 
 	}
 
-	return raidStats, nil
+	return raidStats, scanner.Err()
 }
 
 func (c *megaCliCollector) updateAdapter() error {

collector/meminfo_linux.go

@@ -62,5 +62,5 @@ func parseMemInfo(r io.Reader) (map[string]float64, error) {
 		memInfo[key] = fv
 	}
 
-	return memInfo, nil
+	return memInfo, scanner.Err()
 }

collector/netstat_linux.go

@@ -108,5 +108,5 @@ func parseNetStats(r io.Reader, fileName string) (map[string]map[string]string,
 		}
 	}
 
-	return netStats, nil
+	return netStats, scanner.Err()
 }

collector/sockstat_linux.go

@@ -95,6 +95,9 @@ func parseSockStats(r io.Reader, fileName string) (map[string]map[string]string,
 			i++
 		}
 	}
+	if err := scanner.Err(); err != nil {
+		return nil, err
+	}
 
 	// The mem metrics is the count of pages used. Multiply the mem metrics by
 	// the page size from the kernel to get the number of bytes used.

collector/stat_linux.go

@@ -158,5 +158,5 @@ func (c *statCollector) Update(ch chan<- prometheus.Metric) (err error) {
 			ch <- prometheus.MustNewConstMetric(c.procsBlocked, prometheus.GaugeValue, value)
 		}
 	}
-	return err
+	return scanner.Err()
 }

collector/tcpstat_linux.go

@@ -130,7 +130,7 @@ func parseTCPStats(r io.Reader) (map[tcpConnectionState]float64, error) {
 		tcpStats[tcpConnectionState(st)]++
 	}
 
-	return tcpStats, nil
+	return tcpStats, scanner.Err()
 }
 
 func (st tcpConnectionState) String() string {

collector/vmstat_linux.go

@@ -64,5 +64,5 @@ func (c *vmStatCollector) Update(ch chan<- prometheus.Metric) (err error) {
 			value,
 		)
 	}
-	return err
+	return scanner.Err()
 }