mirror of https://github.com/k3s-io/k3s
137 lines
4.0 KiB
Go
137 lines
4.0 KiB
Go
/*
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Copyright 2017 The Kubernetes Authors.
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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 io
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import (
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"bufio"
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"bytes"
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"io"
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"io/ioutil"
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"time"
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"github.com/sirupsen/logrus"
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runtime "k8s.io/kubernetes/pkg/kubelet/apis/cri/runtime/v1alpha2"
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cioutil "github.com/containerd/cri/pkg/ioutil"
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)
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const (
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// delimiter used in CRI logging format.
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delimiter = ' '
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// eof is end-of-line.
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eol = '\n'
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// timestampFormat is the timestamp format used in CRI logging format.
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timestampFormat = time.RFC3339Nano
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// defaultBufSize is the default size of the read buffer in bytes.
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defaultBufSize = 4096
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)
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// NewDiscardLogger creates logger which discards all the input.
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func NewDiscardLogger() io.WriteCloser {
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return cioutil.NewNopWriteCloser(ioutil.Discard)
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}
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// NewCRILogger returns a write closer which redirect container log into
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// log file, and decorate the log line into CRI defined format. It also
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// returns a channel which indicates whether the logger is stopped.
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// maxLen is the max length limit of a line. A line longer than the
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// limit will be cut into multiple lines.
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func NewCRILogger(path string, w io.Writer, stream StreamType, maxLen int) (io.WriteCloser, <-chan struct{}) {
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logrus.Debugf("Start writing stream %q to log file %q", stream, path)
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prc, pwc := io.Pipe()
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stop := make(chan struct{})
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go func() {
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redirectLogs(path, prc, w, stream, maxLen)
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close(stop)
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}()
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return pwc, stop
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}
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func redirectLogs(path string, rc io.ReadCloser, w io.Writer, s StreamType, maxLen int) {
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defer rc.Close()
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var (
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stream = []byte(s)
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delimiter = []byte{delimiter}
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partial = []byte(runtime.LogTagPartial)
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full = []byte(runtime.LogTagFull)
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buf [][]byte
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length int
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bufSize = defaultBufSize
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)
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// Make sure bufSize <= maxLen
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if maxLen > 0 && maxLen < bufSize {
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bufSize = maxLen
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}
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r := bufio.NewReaderSize(rc, bufSize)
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writeLine := func(tag, line []byte) {
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timestamp := time.Now().AppendFormat(nil, timestampFormat)
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data := bytes.Join([][]byte{timestamp, stream, tag, line}, delimiter)
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data = append(data, eol)
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if _, err := w.Write(data); err != nil {
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logrus.WithError(err).Errorf("Fail to write %q log to log file %q", s, path)
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// Continue on write error to drain the container output.
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}
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}
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for {
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var stop bool
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newLine, isPrefix, err := r.ReadLine()
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if err != nil {
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if err == io.EOF {
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logrus.Debugf("Getting EOF from stream %q while redirecting to log file %q", s, path)
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} else {
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logrus.WithError(err).Errorf("An error occurred when redirecting stream %q to log file %q", s, path)
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}
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if length == 0 {
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// No content left to write, break.
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break
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}
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// Stop after writing the content left in buffer.
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stop = true
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} else {
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// Buffer returned by ReadLine will change after
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// next read, copy it.
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l := make([]byte, len(newLine))
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copy(l, newLine)
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buf = append(buf, l)
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length += len(l)
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}
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if maxLen > 0 && length > maxLen {
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exceedLen := length - maxLen
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last := buf[len(buf)-1]
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if exceedLen > len(last) {
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// exceedLen must <= len(last), or else the buffer
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// should have be written in the previous iteration.
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panic("exceed length should <= last buffer size")
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}
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buf[len(buf)-1] = last[:len(last)-exceedLen]
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writeLine(partial, bytes.Join(buf, nil))
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buf = [][]byte{last[len(last)-exceedLen:]}
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length = exceedLen
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}
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if isPrefix {
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continue
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}
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writeLine(full, bytes.Join(buf, nil))
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buf = nil
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length = 0
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if stop {
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break
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}
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}
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logrus.Debugf("Finish redirecting stream %q to log file %q", s, path)
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}
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