node_exporter/collector/zfs_linux.go

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// Copyright 2016 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package collector
import (
"bufio"
"fmt"
"io"
"os"
"path/filepath"
"strconv"
"strings"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/log"
)
// constants from https://github.com/zfsonlinux/zfs/blob/master/lib/libspl/include/sys/kstat.h
// kept as strings for comparison thus avoiding conversion to int
const (
// kstatDataChar = "0"
// kstatDataInt32 = "1"
// kstatDataUint32 = "2"
// kstatDataInt64 = "3"
kstatDataUint64 = "4"
// kstatDataLong = "5"
// kstatDataUlong = "6"
// kstatDataString = "7"
)
func (c *zfsCollector) openProcFile(path string) (*os.File, error) {
file, err := os.Open(procFilePath(path))
if err != nil {
// file not found error can occur if:
// 1. zfs module is not loaded
// 2. zfs version does not have the feature with metrics -- ok to ignore
log.Debugf("Cannot open %q for reading", procFilePath(path))
return nil, errZFSNotAvailable
}
return file, nil
}
func (c *zfsCollector) updateZfsStats(subsystem string, ch chan<- prometheus.Metric) error {
file, err := c.openProcFile(filepath.Join(c.linuxProcpathBase, c.linuxPathMap[subsystem]))
if err != nil {
return err
}
defer file.Close()
return c.parseProcfsFile(file, c.linuxPathMap[subsystem], func(s zfsSysctl, v uint64) {
ch <- c.constSysctlMetric(subsystem, s, v)
})
}
func (c *zfsCollector) updatePoolStats(ch chan<- prometheus.Metric) error {
zpoolPaths, err := filepath.Glob(procFilePath(filepath.Join(c.linuxProcpathBase, c.linuxZpoolIoPath)))
if err != nil {
return err
}
if zpoolPaths == nil {
return nil
}
for _, zpoolPath := range zpoolPaths {
file, err := os.Open(zpoolPath)
if err != nil {
// this file should exist, but there is a race where an exporting pool can remove the files -- ok to ignore
log.Debugf("Cannot open %q for reading", zpoolPath)
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return errZFSNotAvailable
}
err = c.parsePoolProcfsFile(file, zpoolPath, func(poolName string, s zfsSysctl, v uint64) {
ch <- c.constPoolMetric(poolName, s, v)
})
file.Close()
if err != nil {
return err
}
}
return nil
}
func (c *zfsCollector) parseProcfsFile(reader io.Reader, fmtExt string, handler func(zfsSysctl, uint64)) error {
scanner := bufio.NewScanner(reader)
parseLine := false
for scanner.Scan() {
parts := strings.Fields(scanner.Text())
if !parseLine && len(parts) == 3 && parts[0] == "name" && parts[1] == "type" && parts[2] == "data" {
// Start parsing from here.
parseLine = true
continue
}
if !parseLine || len(parts) < 3 {
continue
}
// kstat data type (column 2) should be KSTAT_DATA_UINT64, otherwise ignore
// TODO: when other KSTAT_DATA_* types arrive, much of this will need to be restructured
if parts[1] == kstatDataUint64 {
key := fmt.Sprintf("kstat.zfs.misc.%s.%s", fmtExt, parts[0])
value, err := strconv.ParseUint(parts[2], 10, 64)
if err != nil {
return fmt.Errorf("could not parse expected integer value for %q", key)
}
handler(zfsSysctl(key), value)
}
}
if !parseLine {
return fmt.Errorf("did not parse a single %q metric", fmtExt)
}
return scanner.Err()
}
func (c *zfsCollector) parsePoolProcfsFile(reader io.Reader, zpoolPath string, handler func(string, zfsSysctl, uint64)) error {
scanner := bufio.NewScanner(reader)
parseLine := false
var fields []string
for scanner.Scan() {
line := strings.Fields(scanner.Text())
if !parseLine && len(line) >= 12 && line[0] == "nread" {
//Start parsing from here.
parseLine = true
fields = make([]string, len(line))
copy(fields, line)
continue
}
if !parseLine {
continue
}
zpoolPathElements := strings.Split(zpoolPath, "/")
pathLen := len(zpoolPathElements)
if pathLen < 2 {
return fmt.Errorf("zpool path did not return at least two elements")
}
zpoolName := zpoolPathElements[pathLen-2]
zpoolFile := zpoolPathElements[pathLen-1]
for i, field := range fields {
key := fmt.Sprintf("kstat.zfs.misc.%s.%s", zpoolFile, field)
value, err := strconv.ParseUint(line[i], 10, 64)
if err != nil {
return fmt.Errorf("could not parse expected integer value for %q: %v", key, err)
}
handler(zpoolName, zfsSysctl(key), value)
}
}
return scanner.Err()
}