Add and use sysReadFile in hwmon collector
@@ -24,6 +24,7 @@ import (
"regexp"
"strconv"
"strings"
+ "syscall"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/log"
@@ -61,8 +62,8 @@ func cleanMetricName(name string) string {
}
func addValueFile(data map[string]map[string]string, sensor string, prop string, file string) {
- raw, e := ioutil.ReadFile(file)
- if e != nil {
+ raw, err := sysReadFile(file)
+ if err != nil {
return
}
value := strings.Trim(string(raw), "\n")
@@ -74,6 +75,28 @@ func addValueFile(data map[string]map[string]string, sensor string, prop string,
data[sensor][prop] = value
}
+// sysReadFile is a simplified ioutil.ReadFile that invokes syscall.Read directly.
+func sysReadFile(file string) ([]byte, error) {
+ f, err := os.Open(file)
+ if err != nil {
+ return nil, err
+ }
+ defer f.Close()
+
+ // On some machines, hwmon drivers are broken and return EAGAIN. This causes
+ // Go's ioutil.ReadFile implementation to poll forever.
+ //
+ // Since we either want to read data or bail immediately, do the simplest
+ // possible read using syscall directly.
+ b := make([]byte, 128)
+ n, err := syscall.Read(int(f.Fd()), b)
+ if err != nil {
+ return nil, err
+ }
+
+ return b[:n], nil
+}
+
// explodeSensorFilename splits a sensor name into <type><num>_<property>.
func explodeSensorFilename(filename string) (ok bool, sensorType string, sensorNum int, sensorProperty string) {
matches := hwmonFilenameFormat.FindStringSubmatch(filename)
