forked from flashcat/categraf
97 lines
2.1 KiB
Go
97 lines
2.1 KiB
Go
//go:build !no_logs && windows
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// Unless explicitly stated otherwise all files in this repository are licensed
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// under the Apache License Version 2.0.
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// This product includes software developed at Datadog (https://www.datadoghq.com/).
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// Copyright 2016-present Datadog, Inc.
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package file
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import (
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"fmt"
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"io"
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"log"
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"os"
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"path/filepath"
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"flashcat.cloud/categraf/logs/decoder"
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)
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// setup sets up the file tailer
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func (t *Tailer) setup(offset int64, whence int) error {
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fullpath, err := filepath.Abs(t.file.Path)
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if err != nil {
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return err
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}
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t.fullpath = fullpath
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// adds metadata to enable users to filter logs by filename
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t.tags = t.buildTailerTags()
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log.Println("Opening ", t.fullpath)
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f, err := openFile(t.fullpath)
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if err != nil {
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return err
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}
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filePos, _ := f.Seek(offset, whence)
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f.Close()
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t.readOffset = filePos
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t.decodedOffset = filePos
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return nil
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}
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func (t *Tailer) readAvailable() (int, error) {
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f, err := openFile(t.fullpath)
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if err != nil {
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return 0, err
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}
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defer f.Close()
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st, err := f.Stat()
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if err != nil {
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log.Println("Error stat()ing file", err)
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return 0, err
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}
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sz := st.Size()
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offset := t.GetReadOffset()
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if sz == 0 {
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log.Println("File size now zero, resetting offset")
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t.SetReadOffset(0)
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t.SetDecodedOffset(0)
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} else if sz < offset {
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log.Println("Offset off end of file, resetting")
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t.SetReadOffset(0)
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t.SetDecodedOffset(0)
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}
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f.Seek(t.GetReadOffset(), io.SeekStart)
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bytes := 0
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for {
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inBuf := make([]byte, 4096)
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n, err := f.Read(inBuf)
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bytes += n
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if n == 0 || err != nil {
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return bytes, err
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}
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t.decoder.InputChan <- decoder.NewInput(inBuf[:n])
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t.incrementReadOffset(n)
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}
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}
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// read lets the tailer tail the content of a file until it is closed. The
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// windows version open and close the file between each call to 'read'. This is
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// needed in order not to block the file and prevent the user from renaming it.
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func (t *Tailer) read() (int, error) {
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n, err := t.readAvailable()
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if err == io.EOF || os.IsNotExist(err) {
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return n, nil
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} else if err != nil {
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t.file.Source.Status.Error(err)
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return n, fmt.Errorf("Err: %s", err)
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}
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return n, nil
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}
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