mirror of
https://github.com/kubernetes/node-problem-detector.git
synced 2026-08-19 12:16:26 +00:00
Ciprian Hacman
b02e2dcd09
Compile fixed patterns during monitor and log counter initialization, pass compiled expressions to the log buffer, and reject invalid log counter patterns before watching logs.
109 lines
2.9 KiB
Go
109 lines
2.9 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 systemlogmonitor
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import (
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"regexp"
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"strings"
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"k8s.io/node-problem-detector/pkg/systemlogmonitor/types"
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)
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// LogBuffer buffers the logs and supports match in the log buffer with regular expression.
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type LogBuffer interface {
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// Push pushes log into the log buffer.
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Push(*types.Log)
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// Match with regular expression in the log buffer.
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Match(*regexp.Regexp) []*types.Log
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// String returns a concatenated string of the buffered logs.
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String() string
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}
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type logBuffer struct {
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// buffer is a simple ring buffer.
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buffer []*types.Log
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msg []string
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max int
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current int
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}
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// NewLogBuffer creates log buffer with max line number limit. Because we only match logs
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// in the log buffer, the max buffer line number is also the max pattern line number we
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// support. Smaller buffer line number means less memory and cpu usage, but also means less
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// lines of patterns we support.
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func NewLogBuffer(maxLines int) *logBuffer {
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return &logBuffer{
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buffer: make([]*types.Log, maxLines),
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msg: make([]string, maxLines),
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max: maxLines,
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}
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}
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// CompilePattern compiles a log buffer pattern that must match to the end of
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// the buffered logs.
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func CompilePattern(expr string) (*regexp.Regexp, error) {
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if _, err := regexp.Compile(expr); err != nil {
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return nil, err
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}
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return regexp.Compile(expr + `\z`)
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}
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func (b *logBuffer) Push(log *types.Log) {
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b.buffer[b.current%b.max] = log
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b.msg[b.current%b.max] = log.Message
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b.current++
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}
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func (b *logBuffer) Match(reg *regexp.Regexp) []*types.Log {
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log := b.String()
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loc := reg.FindStringIndex(log)
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if loc == nil {
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// No match
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return nil
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}
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// reverse index
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s := len(log) - loc[0] - 1
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total := 0
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matched := []*types.Log{}
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for i := b.tail(); i >= b.current && b.buffer[i%b.max] != nil; i-- {
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matched = append(matched, b.buffer[i%b.max])
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total += len(b.msg[i%b.max]) + 1 // Add '\n'
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if total > s {
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break
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}
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}
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for i := 0; i < len(matched)/2; i++ {
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matched[i], matched[len(matched)-i-1] = matched[len(matched)-i-1], matched[i]
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}
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return matched
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}
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func (b *logBuffer) String() string {
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logs := append(b.msg[b.current%b.max:], b.msg[:b.current%b.max]...)
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return concatLogs(logs)
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}
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// tail returns current tail index.
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func (b *logBuffer) tail() int {
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return b.current + b.max - 1
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}
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// concatLogs concatenates multiple lines of logs into one string.
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func concatLogs(logs []string) string {
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return strings.Join(logs, "\n")
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}
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