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log.go
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log.go
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package harvester
import (
"errors"
"fmt"
"io"
"os"
"github.com/elastic/beats/filebeat/config"
"github.com/elastic/beats/filebeat/harvester/encoding"
"github.com/elastic/beats/filebeat/harvester/processor"
"github.com/elastic/beats/filebeat/input"
"github.com/elastic/beats/libbeat/logp"
"golang.org/x/text/transform"
)
const (
defaultMaxBytes = 10 * (1 << 20) // 10MB
)
func NewHarvester(
prospectorCfg config.ProspectorConfig,
cfg *config.HarvesterConfig,
path string,
stat *FileStat,
spooler chan *input.FileEvent,
) (*Harvester, error) {
var err error
encoding, ok := encoding.FindEncoding(cfg.Encoding)
if !ok || encoding == nil {
return nil, fmt.Errorf("unknown encoding('%v')", cfg.Encoding)
}
h := &Harvester{
Path: path,
ProspectorConfig: prospectorCfg,
Config: cfg,
Stat: stat,
SpoolerChan: spooler,
encoding: encoding,
}
h.ExcludeLinesRegexp, err = InitRegexps(cfg.ExcludeLines)
if err != nil {
return h, err
}
h.IncludeLinesRegexp, err = InitRegexps(cfg.IncludeLines)
if err != nil {
return h, err
}
return h, nil
}
func createLineReader(
in FileSource,
codec encoding.Encoding,
bufferSize int,
maxBytes int,
readerConfig logFileReaderConfig,
mlrConfig *config.MultilineConfig,
) (processor.LineProcessor, error) {
var p processor.LineProcessor
var err error
fileReader, err := newLogFileReader(in, readerConfig)
if err != nil {
return nil, err
}
p, err = processor.NewLineSource(fileReader, codec, bufferSize)
if err != nil {
return nil, err
}
if mlrConfig != nil {
p, err = processor.NewMultiline(p, maxBytes, mlrConfig)
if err != nil {
return nil, err
}
return processor.NewStripNewline(p), nil
}
p = processor.NewStripNewline(p)
return processor.NewLimitProcessor(p, maxBytes), nil
}
// Log harvester reads files line by line and sends events to the defined output
func (h *Harvester) Harvest() {
defer func() {
// On completion, push offset so we can continue where we left off if we relaunch on the same file
if h.Stat != nil {
h.Stat.Return <- h.GetOffset()
}
// Make sure file is closed as soon as harvester exits
// If file was never properly opened, it can't be closed
if h.file != nil {
h.file.Close()
logp.Debug("harvester", "Closing file: %s", h.Path)
}
}()
enc, err := h.open()
if err != nil {
logp.Err("Stop Harvesting. Unexpected file opening error: %s", err)
return
}
info, err := h.file.Stat()
if err != nil {
logp.Err("Stop Harvesting. Unexpected file stat rror: %s", err)
return
}
logp.Info("Harvester started for file: %s", h.Path)
// TODO: NewLineReader uses additional buffering to deal with encoding and testing
// for new lines in input stream. Simple 8-bit based encodings, or plain
// don't require 'complicated' logic.
config := h.Config
readerConfig := logFileReaderConfig{
forceClose: config.ForceCloseFiles,
closeOlderDuration: h.ProspectorConfig.CloseOlderDuration,
backoffDuration: config.BackoffDuration,
maxBackoffDuration: config.MaxBackoffDuration,
backoffFactor: config.BackoffFactor,
}
maxBytes := defaultMaxBytes
if config.MaxBytes != nil {
maxBytes = *config.MaxBytes
}
reader, err := createLineReader(
h.file, enc, config.BufferSize, maxBytes, readerConfig, config.Multiline)
if err != nil {
logp.Err("Stop Harvesting. Unexpected encoding line reader error: %s", err)
return
}
for {
// Partial lines return error and are only read on completion
ts, text, bytesRead, err := readLine(reader)
if err != nil {
if err == errFileTruncate {
seeker, ok := h.file.(io.Seeker)
if !ok {
logp.Err("can not seek source")
return
}
logp.Info("File was truncated. Begin reading file from offset 0: %s", h.Path)
h.SetOffset(0)
seeker.Seek(h.GetOffset(), os.SEEK_SET)
continue
}
logp.Info("Read line error: %s", err)
return
}
if h.shouldExportLine(text) {
// Sends text to spooler
event := &input.FileEvent{
ReadTime: ts,
Source: h.Path,
InputType: h.Config.InputType,
DocumentType: h.Config.DocumentType,
Offset: h.GetOffset(),
Bytes: bytesRead,
Text: &text,
Fields: &h.Config.Fields,
Fileinfo: &info,
}
event.SetFieldsUnderRoot(h.Config.FieldsUnderRoot)
h.SpoolerChan <- event // ship the new event downstream
}
// Set Offset
h.SetOffset(h.GetOffset() + int64(bytesRead)) // Update offset if complete line has been processed
}
}
// shouldExportLine decides if the line is exported or not based on
// the include_lines and exclude_lines options.
func (h *Harvester) shouldExportLine(line string) bool {
if len(h.IncludeLinesRegexp) > 0 {
if !MatchAnyRegexps(h.IncludeLinesRegexp, line) {
// drop line
logp.Debug("harvester", "Drop line as it does not match any of the include patterns %s", line)
return false
}
}
if len(h.ExcludeLinesRegexp) > 0 {
if MatchAnyRegexps(h.ExcludeLinesRegexp, line) {
// drop line
logp.Debug("harvester", "Drop line as it does match one of the exclude patterns%s", line)
return false
}
}
return true
}
// open does open the file given under h.Path and assigns the file handler to h.file
func (h *Harvester) open() (encoding.Encoding, error) {
// Special handling that "-" means to read from standard input
if h.Config.InputType == config.StdinInputType {
return h.openStdin()
}
return h.openFile()
}
func (h *Harvester) openStdin() (encoding.Encoding, error) {
h.file = pipeSource{os.Stdin}
return h.encoding(h.file)
}
// openFile opens a file and checks for the encoding. In case the encoding cannot be detected
// or the file cannot be opened because for example of failing read permissions, an error
// is returned and the harvester is closed. The file will be picked up again the next time
// the file system is scanned
func (h *Harvester) openFile() (encoding.Encoding, error) {
var file *os.File
var err error
var encoding encoding.Encoding
file, err = input.ReadOpen(h.Path)
if err != nil {
logp.Err("Failed opening %s: %s", h.Path, err)
return nil, err
}
// Closes file handler in case of follow up error
defer func() {
if err != nil {
file.Close()
}
}()
// Check we are not following a rabbit hole (symlinks, etc.)
if !input.IsRegularFile(file) {
return nil, errors.New("Given file is not a regular file.")
}
encoding, err = h.encoding(file)
if err != nil {
if err == transform.ErrShortSrc {
logp.Info("Initialising encoding for '%v' failed due to file being too short", file)
} else {
logp.Err("Initialising encoding for '%v' failed: %v", file, err)
}
return nil, err
}
// update file offset
err = h.initFileOffset(file)
if err != nil {
return nil, err
}
// yay, open file
h.file = fileSource{file}
return encoding, nil
}
func (h *Harvester) initFileOffset(file *os.File) error {
offset, err := file.Seek(0, os.SEEK_CUR)
if h.GetOffset() > 0 {
// continue from last known offset
logp.Debug("harvester",
"harvest: %q position:%d (offset snapshot:%d)", h.Path, h.GetOffset(), offset)
_, err = file.Seek(h.GetOffset(), os.SEEK_SET)
} else if h.Config.TailFiles {
// tail file if file is new and tail_files config is set
logp.Debug("harvester",
"harvest: (tailing) %q (offset snapshot:%d)", h.Path, offset)
offset, err = file.Seek(0, os.SEEK_END)
h.SetOffset(offset)
} else {
// get offset from file in case of encoding factory was
// required to read some data.
logp.Debug("harvester", "harvest: %q (offset snapshot:%d)", h.Path, offset)
h.SetOffset(offset)
}
return err
}
func (h *Harvester) Stop() {
}
const maxConsecutiveEmptyReads = 100
// GetState returns current state of harvester
func (h *Harvester) GetState() *input.FileState {
state := input.FileState{
Source: h.Path,
Offset: h.GetOffset(),
FileStateOS: input.GetOSFileState(&h.Stat.Fileinfo),
}
return &state
}
func (h *Harvester) SetOffset(offset int64) {
h.offsetLock.Lock()
defer h.offsetLock.Unlock()
h.offset = offset
}
func (h *Harvester) SetPath(path string) {
h.offsetLock.Lock()
defer h.offsetLock.Unlock()
h.Path = path
}
func (h *Harvester) GetOffset() int64 {
h.offsetLock.Lock()
defer h.offsetLock.Unlock()
return h.offset
}