forked from google/cadvisor
/
oomparser.go
205 lines (186 loc) · 6.06 KB
/
oomparser.go
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// Copyright 2014 Google Inc. All Rights Reserved.
//
// 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 oomparser
import (
"bufio"
"fmt"
"io"
"os"
"path"
"regexp"
"strconv"
"time"
"github.com/golang/glog"
"github.com/google/cadvisor/utils"
)
var containerRegexp *regexp.Regexp = regexp.MustCompile(
`Task in (.*) killed as a result of limit of `)
var lastLineRegexp *regexp.Regexp = regexp.MustCompile(
`(^[A-Z]{1}[a-z]{2} .*[0-9]{1,2} [0-9]{1,2}:[0-9]{2}:[0-9]{2}) .* Killed process ([0-9]+) \(([0-9A-Za-z_]+)\)`)
var firstLineRegexp *regexp.Regexp = regexp.MustCompile(
`invoked oom-killer:`)
// struct to hold file from which we obtain OomInstances
type OomParser struct {
systemFile string
}
// struct that contains information related to an OOM kill instance
type OomInstance struct {
// process id of the killed process
Pid int
// the name of the killed process
ProcessName string
// the time that the process was reported to be killed,
// accurate to the minute
TimeOfDeath time.Time
// the absolute name of the container that OOMed
ContainerName string
}
// gets the container name from a line and adds it to the oomInstance.
func getContainerName(line string, currentOomInstance *OomInstance) error {
parsedLine := containerRegexp.FindStringSubmatch(line)
if parsedLine == nil {
return nil
}
currentOomInstance.ContainerName = path.Join("/", parsedLine[1])
return nil
}
// gets the pid, name, and date from a line and adds it to oomInstance
func getProcessNamePid(line string, currentOomInstance *OomInstance) (bool, error) {
reList := lastLineRegexp.FindStringSubmatch(line)
if reList == nil {
return false, nil
}
const longForm = "Jan _2 15:04:05 2006"
stringYear := strconv.Itoa(time.Now().Year())
linetime, err := time.ParseInLocation(longForm, reList[1]+" "+stringYear, time.Local)
if err != nil {
return false, err
}
currentOomInstance.TimeOfDeath = linetime
pid, err := strconv.Atoi(reList[2])
if err != nil {
return false, err
}
currentOomInstance.Pid = pid
currentOomInstance.ProcessName = reList[3]
return true, nil
}
// uses regex to see if line is the start of a kernel oom log
func checkIfStartOfOomMessages(line string) bool {
potential_oom_start := firstLineRegexp.MatchString(line)
if potential_oom_start {
return true
}
return false
}
// reads the file and sends only complete lines over a channel to analyzeLines.
// Should prevent EOF errors that occur when lines are read before being fully
// written to the log. It reads line by line splitting on
// the "\n" character.
func readLinesFromFile(lineChannel chan string, ioreader *bufio.Reader) {
linefragment := ""
var line string
var err error
for true {
line, err = ioreader.ReadString('\n')
if err == io.EOF {
if line != "" {
linefragment += line
}
time.Sleep(100 * time.Millisecond)
} else if err == nil {
if linefragment != "" {
line = linefragment + line
linefragment = ""
}
lineChannel <- line
} else if err != nil && err != io.EOF {
glog.Errorf("exiting analyzeLinesHelper with error %v", err)
}
}
}
// Calls goroutine for analyzeLinesHelper, which feeds it complete lines.
// Lines are checked against a regexp to check for the pid, process name, etc.
// At the end of an oom message group, AnalyzeLines adds the new oomInstance to
// oomLog
func (self *OomParser) analyzeLines(ioreader *bufio.Reader, outStream chan *OomInstance) {
lineChannel := make(chan string, 10)
go func() {
readLinesFromFile(lineChannel, ioreader)
}()
for line := range lineChannel {
in_oom_kernel_log := checkIfStartOfOomMessages(line)
if in_oom_kernel_log {
oomCurrentInstance := &OomInstance{
ContainerName: "/",
}
finished := false
for !finished {
err := getContainerName(line, oomCurrentInstance)
if err != nil {
glog.Errorf("%v", err)
}
finished, err = getProcessNamePid(line, oomCurrentInstance)
if err != nil {
glog.Errorf("%v", err)
}
line = <-lineChannel
}
in_oom_kernel_log = false
outStream <- oomCurrentInstance
}
}
glog.Infof("exiting analyzeLines")
}
// looks for system files that contain kernel messages and if one is found, sets
// the systemFile attribute of the OomParser object
func getSystemFile() (string, error) {
const varLogMessages = "/var/log/messages"
const varLogSyslog = "/var/log/syslog"
if utils.FileExists(varLogMessages) {
return varLogMessages, nil
} else if utils.FileExists(varLogSyslog) {
return varLogSyslog, nil
}
return "", fmt.Errorf("neither %s nor %s exists from which to read kernel errors", varLogMessages, varLogSyslog)
}
// calls a go routine that populates self.OomInstances and fills the argument
// channel with OomInstance objects as they are read from the file.
// opens the OomParser's systemFile which was set in getSystemFile
// to look for OOM messages by calling AnalyzeLines. Takes in the argument
// outStream, which is passed in by the user and passed to AnalyzeLines.
// OomInstance objects are added to outStream when they are found by
// AnalyzeLines
func (self *OomParser) StreamOoms(outStream chan *OomInstance) error {
file, err := os.Open(self.systemFile)
if err != nil {
return err
}
ioreader := bufio.NewReader(file)
// Process the events received from the kernel.
go func() {
self.analyzeLines(ioreader, outStream)
}()
return nil
}
// initializes an OomParser object and calls getSystemFile to set the systemFile
// attribute. Returns and OomParser object and an error
func New() (*OomParser, error) {
systemFileName, err := getSystemFile()
if err != nil {
return nil, err
}
return &OomParser{
systemFile: systemFileName}, nil
}