mirror of
https://github.com/kubernetes/node-problem-detector.git
synced 2026-03-05 19:20:26 +00:00
103 lines
3.3 KiB
Go
103 lines
3.3 KiB
Go
/*
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Copyright 2016 The Kubernetes Authors All rights reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package syslog
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import (
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"fmt"
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"io"
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"os"
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"strings"
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"time"
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kerntypes "k8s.io/node-problem-detector/pkg/kernelmonitor/types"
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"github.com/google/cadvisor/utils/tail"
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)
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// translate translates the log line into internal type.
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func translate(line string) (*kerntypes.KernelLog, error) {
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timestamp, message, err := parseLine(line)
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if err != nil {
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return nil, err
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}
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return &kerntypes.KernelLog{
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Timestamp: timestamp,
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Message: message,
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}, nil
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}
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const (
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// timestampLen is the length of timestamp in syslog logging format.
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timestampLen = 15
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// messagePrefix is the character before real message.
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messagePrefix = "]"
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)
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// parseLine parses one log line into timestamp and message.
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func parseLine(line string) (time.Time, string, error) {
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// Trim the spaces to make sure timestamp could be found
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line = strings.TrimSpace(line)
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if len(line) < timestampLen {
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return time.Time{}, "", fmt.Errorf("the line is too short: %q", line)
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}
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// Example line: Jan 1 00:00:00 hostname kernel: [0.000000] component: log message
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now := time.Now()
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// There is no time zone information in kernel log timestamp, apply the current time
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// zone.
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timestamp, err := time.ParseInLocation(time.Stamp, line[:timestampLen], time.Local)
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if err != nil {
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return time.Time{}, "", fmt.Errorf("error parsing timestamp in line %q: %v", line, err)
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}
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// There is no year information in kernel log timestamp, apply the current year.
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// This could go wrong during looking back phase after kernel monitor is started,
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// and the old logs are generated in old year.
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timestamp = timestamp.AddDate(now.Year(), 0, 0)
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loc := strings.Index(line, messagePrefix)
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if loc == -1 {
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return timestamp, "", fmt.Errorf("can't find message prefix %q in line %q", messagePrefix, line)
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}
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message := strings.Trim(line[loc+1:], " ")
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return timestamp, message, nil
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}
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// defaultKernelLogPath the default path of syslog kernel log.
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const defaultKernelLogPath = "/var/log/kern.log"
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// getLogReader returns log reader for syslog log. Note that getLogReader doesn't look back
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// to the rolled out logs.
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func getLogReader(path string) (io.ReadCloser, error) {
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if path == "" {
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path = defaultKernelLogPath
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}
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// To handle log rotation, tail will not report error immediately if
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// the file doesn't exist. So we check file existence frist.
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// This could go wrong during mid-rotation. It should recover after
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// several restart when the log file is created again. The chance
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// is slim but we should still fix this in the future.
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// TODO(random-liu): Handle log missing during rotation.
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_, err := os.Stat(path)
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if err != nil {
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return nil, fmt.Errorf("failed to stat the file %q: %v", path, err)
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}
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tail, err := tail.NewTail(path)
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if err != nil {
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return nil, fmt.Errorf("failed to tail the file %q: %v", path, err)
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}
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return tail, nil
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}
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