node_exporter/collector/diskstats_linux.go

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// Copyright 2015 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.
// +build !nodiskstats
package collector
import (
"bufio"
"flag"
"fmt"
"io"
"os"
"regexp"
"strconv"
"strings"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/log"
)
const (
diskSubsystem = "disk"
)
var (
ignoredDevices = flag.String("collector.diskstats.ignored-devices", "^(ram|loop|fd|(h|s|v|xv)d[a-z])\\d+$", "Regexp of devices to ignore for diskstats.")
)
type diskstatsCollector struct {
ignoredDevicesPattern *regexp.Regexp
metrics []prometheus.Collector
}
func init() {
Factories["diskstats"] = NewDiskstatsCollector
}
// Takes a prometheus registry and returns a new Collector exposing
// disk device stats.
func NewDiskstatsCollector() (Collector, error) {
var diskLabelNames = []string{"device"}
return &diskstatsCollector{
ignoredDevicesPattern: regexp.MustCompile(*ignoredDevices),
// Docs from https://www.kernel.org/doc/Documentation/iostats.txt
metrics: []prometheus.Collector{
prometheus.NewCounterVec(
prometheus.CounterOpts{
Namespace: Namespace,
Subsystem: diskSubsystem,
Name: "reads_completed",
Help: "The total number of reads completed successfully.",
},
diskLabelNames,
),
prometheus.NewCounterVec(
prometheus.CounterOpts{
Namespace: Namespace,
Subsystem: diskSubsystem,
Name: "reads_merged",
Help: "The number of reads merged. See https://www.kernel.org/doc/Documentation/iostats.txt.",
},
diskLabelNames,
),
prometheus.NewCounterVec(
prometheus.CounterOpts{
Namespace: Namespace,
Subsystem: diskSubsystem,
Name: "sectors_read",
Help: "The total number of sectors read successfully.",
},
diskLabelNames,
),
prometheus.NewCounterVec(
prometheus.CounterOpts{
Namespace: Namespace,
Subsystem: diskSubsystem,
Name: "read_time_ms",
Help: "The total number of milliseconds spent by all reads.",
},
diskLabelNames,
),
prometheus.NewCounterVec(
prometheus.CounterOpts{
Namespace: Namespace,
Subsystem: diskSubsystem,
Name: "writes_completed",
Help: "The total number of writes completed successfully.",
},
diskLabelNames,
),
prometheus.NewCounterVec(
prometheus.CounterOpts{
Namespace: Namespace,
Subsystem: diskSubsystem,
Name: "writes_merged",
Help: "The number of writes merged. See https://www.kernel.org/doc/Documentation/iostats.txt.",
},
diskLabelNames,
),
prometheus.NewCounterVec(
prometheus.CounterOpts{
Namespace: Namespace,
Subsystem: diskSubsystem,
Name: "sectors_written",
Help: "The total number of sectors written successfully.",
},
diskLabelNames,
),
prometheus.NewCounterVec(
prometheus.CounterOpts{
Namespace: Namespace,
Subsystem: diskSubsystem,
Name: "write_time_ms",
Help: "This is the total number of milliseconds spent by all writes.",
},
diskLabelNames,
),
prometheus.NewGaugeVec(
prometheus.GaugeOpts{
Namespace: Namespace,
Subsystem: diskSubsystem,
Name: "io_now",
Help: "The number of I/Os currently in progress.",
},
diskLabelNames,
),
prometheus.NewCounterVec(
prometheus.CounterOpts{
Namespace: Namespace,
Subsystem: diskSubsystem,
Name: "io_time_ms",
Help: "Milliseconds spent doing I/Os.",
},
diskLabelNames,
),
prometheus.NewCounterVec(
prometheus.CounterOpts{
Namespace: Namespace,
Subsystem: diskSubsystem,
Name: "io_time_weighted",
Help: "The weighted # of milliseconds spent doing I/Os. See https://www.kernel.org/doc/Documentation/iostats.txt.",
},
diskLabelNames,
),
},
}, nil
}
func (c *diskstatsCollector) Update(ch chan<- prometheus.Metric) (err error) {
procDiskStats := procFilePath("diskstats")
diskStats, err := getDiskStats()
if err != nil {
return fmt.Errorf("couldn't get diskstats: %s", err)
}
for dev, stats := range diskStats {
if c.ignoredDevicesPattern.MatchString(dev) {
log.Debugf("Ignoring device: %s", dev)
continue
}
if len(stats) != len(c.metrics) {
return fmt.Errorf("invalid line for %s for %s", procDiskStats, dev)
}
for k, value := range stats {
v, err := strconv.ParseFloat(value, 64)
if err != nil {
return fmt.Errorf("invalid value %s in diskstats: %s", value, err)
}
if counter, ok := c.metrics[k].(*prometheus.CounterVec); ok {
counter.WithLabelValues(dev).Set(v)
} else if gauge, ok := c.metrics[k].(*prometheus.GaugeVec); ok {
gauge.WithLabelValues(dev).Set(v)
} else {
return fmt.Errorf("unexpected collector %d", k)
}
}
}
for _, c := range c.metrics {
c.Collect(ch)
}
return err
}
func getDiskStats() (map[string]map[int]string, error) {
file, err := os.Open(procFilePath("diskstats"))
if err != nil {
return nil, err
}
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defer file.Close()
return parseDiskStats(file)
}
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func parseDiskStats(r io.Reader) (map[string]map[int]string, error) {
var (
diskStats = map[string]map[int]string{}
scanner = bufio.NewScanner(r)
)
for scanner.Scan() {
parts := strings.Fields(string(scanner.Text()))
if len(parts) < 4 { // we strip major, minor and dev
return nil, fmt.Errorf("invalid line in %s: %s", procFilePath("diskstats"), scanner.Text())
}
dev := parts[2]
diskStats[dev] = map[int]string{}
for i, v := range parts[3:] {
diskStats[dev][i] = v
}
}
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return diskStats, nil
}