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tail.go
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tail.go
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/*
* tail.go - file agent data structure and funtions to tail file
*
* history
* --------------------
* 2017/8/18, by Ye Zhiqin, create
* 2017/9/30, by Ye Zhiqin, modify
* 2018/1/3, by Ye Zhiqin, modify
*
* DESCRIPTION
* This file contains the definition of file agent
* and the functions to tail log file
*/
package main
import (
"bytes"
"fmt"
"io"
"log"
"os"
"path"
"time"
"github.com/fsnotify/fsnotify"
)
type FileAgent struct {
Filename string
File *os.File
FileInfo os.FileInfo
LastOffset int64
UnchangeTime int
Delimiter string
TsEnabled bool
TsPattern string
InotifyEnabled bool
Tasks []*AgentTask
}
type AgentTask struct {
Metric string
Tags string
CounterType string
Step int64
Pattern string
Reversed bool
Threshold float64
Method string
TsStart int64
TsEnd int64
TsUpdate int64
ValueCnt int64
ValueMax float64
ValueMin float64
ValueSum float64
}
/*
* Report - push and update data after a period passed
*
* RECEIVER: *FileAgent
*
* PARAMS:
* - ts: timestamp
* - tsEnabled: is log file timestamp enabled
*
* RETURNS:
* No paramter
*/
func (task *AgentTask) Report(ts time.Time, timeup bool) {
var data []*FalconData
if task.Method == "count" {
metricCnt := task.Metric + ".cnt"
point := NewFalconData(metricCnt, config.Falcon.Endpoint, task.ValueCnt, task.CounterType, task.Tags, task.TsEnd, task.Step)
data = append(data, point)
}
if task.Method == "Tcount" {
metricCnt := task.Metric + ".tcnt"
point := NewFalconData(metricCnt, config.Falcon.Endpoint, task.ValueCnt, task.CounterType, task.Tags, task.TsEnd, task.Step)
data = append(data, point)
}
if task.Method == "statistic" {
metricCnt := task.Metric + ".cnt"
point := NewFalconData(metricCnt, config.Falcon.Endpoint, task.ValueCnt, task.CounterType, task.Tags, task.TsEnd, task.Step)
data = append(data, point)
metricMax := task.Metric + ".max"
point = NewFalconData(metricMax, config.Falcon.Endpoint, task.ValueMax, task.CounterType, task.Tags, task.TsEnd, task.Step)
data = append(data, point)
metricMin := task.Metric + ".min"
if task.ValueMin > task.ValueMax {
point = NewFalconData(metricMin, config.Falcon.Endpoint, 0, task.CounterType, task.Tags, task.TsEnd, task.Step)
data = append(data, point)
} else {
point = NewFalconData(metricMin, config.Falcon.Endpoint, task.ValueMin, task.CounterType, task.Tags, task.TsEnd, task.Step)
data = append(data, point)
}
metricAvg := task.Metric + ".avg"
if task.ValueCnt == 0 {
point = NewFalconData(metricAvg, config.Falcon.Endpoint, 0, task.CounterType, task.Tags, task.TsEnd, task.Step)
data = append(data, point)
} else {
point = NewFalconData(metricAvg, config.Falcon.Endpoint, task.ValueSum/float64(task.ValueCnt), task.CounterType, task.Tags, task.TsEnd, task.Step)
data = append(data, point)
}
}
log.Printf("falcon point: %v", data)
response, err := PushData(config.Falcon.Url, data)
if err != nil {
log.Printf("push data to falcon FAIL: %v", err)
}
log.Printf("push data to falcon succeed: %s", string(response))
// update value
task.ValueCnt = 0
task.ValueMax = 0
task.ValueMin = 1 << 32
task.ValueSum = 0
//update timestamp
if timeup {
task.TsStart += task.Step
task.TsEnd += task.Step
task.TsUpdate = task.TsEnd - 1
} else {
task.TsStart += task.Step
task.TsEnd += task.Step
task.TsUpdate = ts.Unix()
}
}
/*
* Timeup - the process after a period passed
*
* RECEIVER: *FileAgent
*
* PARAMS:
* No paramter
*
* RETURNS:
* No paramter
*/
func (fa *FileAgent) Timeup() {
ts := time.Now()
for _, task := range fa.Tasks {
if fa.TsEnabled {
if ts.Unix()-task.TsUpdate >= task.Step {
//push data and update task when the time between now and last update time is longer than a step
task.Report(ts, true)
}
} else {
if ts.Unix()-task.TsStart >= task.Step {
//push data and update task when the time between now and start time is longer than a step
task.Report(ts, true)
}
}
}
}
/*
* MatchLine - process each line of log
*
* RECEIVER: *FileAgent
*
* PARAMS:
* - line: a line of log file
*
* RETURNS:
* No paramter
*/
func (fa *FileAgent) MatchLine(line []byte) {
if fa.TsEnabled {
isTsMatched, ts, err := MatchTs(line, fa.TsPattern)
if err != nil || !isTsMatched {
return
}
for _, task := range fa.Tasks {
//push data and update task when the timestamp is not in current period
if ts.Unix() > task.TsEnd || ts.Unix() < task.TsStart {
log.Printf("timestamp updated!")
task.Report(ts, false)
}
if task.Method == "count" {
isKeywordMatched, err := MatchKeyword(line, task.Pattern, task.Reversed)
if err != nil || !isKeywordMatched {
continue
}
task.ValueCnt += 1
task.TsUpdate = ts.Unix()
}
if task.Method == "Tcount" {
isCostMatched, cost, err := MatchCost(line, task.Pattern)
if err != nil || !isCostMatched {
continue
}
if cost > task.Threshold {
task.ValueCnt += 1
}
}
if task.Method == "statistic" {
isCostMatched, cost, err := MatchCost(line, task.Pattern)
if err != nil || !isCostMatched {
continue
}
task.ValueCnt += 1
if task.ValueMax < cost {
task.ValueMax = cost
}
if task.ValueMin > cost {
task.ValueMin = cost
}
task.ValueSum += cost
task.TsUpdate = ts.Unix()
}
}
} else {
for _, task := range fa.Tasks {
if task.Method == "count" {
isKeywordMatched, err := MatchKeyword(line, task.Pattern, task.Reversed)
if err != nil || !isKeywordMatched {
continue
}
task.ValueCnt += 1
}
if task.Method == "Tcount" {
isCostMatched, cost, err := MatchCost(line, task.Pattern)
if err != nil || !isCostMatched {
continue
}
if cost > task.Threshold {
task.ValueCnt += 1
}
}
if task.Method == "statistic" {
isCostMatched, cost, err := MatchCost(line, task.Pattern)
if err != nil || !isCostMatched {
continue
}
task.ValueCnt += 1
if task.ValueMax < cost {
task.ValueMax = cost
}
if task.ValueMin > cost {
task.ValueMin = cost
}
task.ValueSum += cost
}
}
}
}
/*
* ReadRemainder - reading new bytes of log file
*
* RECEIVER: *FileAgent
*
* PARAMS:
* No paramter
*
* RETURNS:
* nil: succeed
* error: fail
*/
func (fa *FileAgent) ReadRemainder() error {
tailable := fa.FileInfo.Mode().IsRegular()
size := fa.FileInfo.Size()
// LastOffset less then new size. Maybe the file has been truncated.
if tailable && fa.LastOffset > size {
// seek the cursor to the header of new file
offset, err := fa.File.Seek(0, os.SEEK_SET)
if err != nil {
log.Printf("file %s seek FAIL: %v", fa.Filename, err)
return err
}
if offset != 0 {
log.Printf("offset is not equal 0")
}
fa.LastOffset = 0
return nil
}
bufsize := size - fa.LastOffset
if bufsize == 0 {
return nil
}
data := make([]byte, bufsize)
readsize, err := fa.File.Read(data)
if err != nil && err != io.EOF {
log.Printf("file %s read FAIL: %v", err)
return err
}
if readsize == 0 {
log.Printf("file %s read 0 data", fa.Filename)
return nil
}
if fa.Delimiter == "" {
fa.Delimiter = "\n"
}
sep := []byte(fa.Delimiter)
lines := bytes.SplitAfter(data, sep)
length := len(lines)
for idx, line := range lines {
// just process entire line with the delimiter
if idx == length-1 {
backsize := len(line)
movesize := readsize - backsize
_, err := fa.File.Seek(-int64(backsize), os.SEEK_CUR)
if err != nil {
log.Printf("seek file %s FAIL: %v", fa.Filename, err)
return err
}
fa.LastOffset += int64(movesize)
break
}
fa.MatchLine(line)
}
return nil
}
/*
* TailWithCheck - tail log file in a loop
*
* PARAMS:
* - fa: file agent
* - finish: a channel to receiver stop signal
*
* RETURNS:
* No return value
*/
func TailWithCheck(fa *FileAgent, finish <-chan bool) {
log.Printf("agent for %s is launching...", fa.Filename)
// create one second ticker
ticker := time.NewTicker(time.Second * 1)
defer ticker.Stop()
TAIL:
for {
select {
case <-finish:
if fa.File != nil {
if err := fa.File.Close(); err != nil {
log.Printf("file closing FAIL: %v", err)
}
}
break TAIL
case <-ticker.C:
fa.Timeup()
default:
fa.TryReading()
time.Sleep(time.Millisecond * 100)
}
}
wg.Done()
log.Printf("wg: %v", wg)
log.Printf("agent for %s is exiting...", fa.Filename)
}
/*
* TryReading - reading log file
*
* RECEIVER: *FileAgent
*
* PARAMS:
* No paramter
*
* RETURNS:
* No return value
*/
func (fa *FileAgent) TryReading() {
if fa.File == nil {
log.Printf("file %s is nil", fa.Filename)
if err := fa.FileRecheck(); err != nil {
log.Printf("file recheck FAIL: %v", err)
}
return
}
if !fa.IsChanged() {
if fa.UnchangeTime >= MAX_UNCHANGED_TIME {
fa.FileRecheck()
}
return
}
fa.ReadRemainder()
}
/*
* TailWithInotify - trace log file
*
* PARAMS:
* - fa: file agent
* - finish: a channel to receiver stop signal
*
* RETURNS:
* No return value
*/
func TailWithInotify(fa *FileAgent, chanFinish <-chan bool) {
fmt.Printf("agent for %s is starting...\n", fa.Filename)
// create one second ticker
ticker := time.NewTicker(time.Second * 1)
defer ticker.Stop()
// craete file watcher
watcher, err := fsnotify.NewWatcher()
if err != nil {
log.Printf("watcher creating FAIL: %s", err.Error())
wg.Done()
log.Printf("agent for %s is exiting...", fa.Filename)
return
}
defer watcher.Close()
// add parent directory to watcher
dir := path.Dir(fa.Filename)
if err := watcher.Add(dir); err != nil {
log.Printf("add %s to watcher FAIL: %s", dir, err.Error())
wg.Done()
log.Printf("agent for %s is exiting...", fa.Filename)
return
}
// open file and initialize file agent
if err := fa.FileOpen(); err != nil {
log.Printf("file $s open FAIL when agent initializing: %s", fa.Filename, err.Error())
}
// trace file in this loop
TRACE:
for {
select {
case <-chanFinish:
if err := watcher.Remove(dir); err != nil {
log.Printf("watcher file removing FAIL: %s", err.Error())
}
if fa.File != nil {
if err := fa.File.Close(); err != nil {
log.Printf("file closing FAIL: %s", err.Error())
}
}
break TRACE
case event := <-watcher.Events:
if event.Name == fa.Filename {
// WRITE event
if 2 == event.Op {
if err := fa.FileInfoUpdate(); err != nil {
log.Printf("file %s stat FAIL", fa.Filename)
if fa.UnchangeTime > MAX_UNCHANGED_TIME {
fa.FileReopen()
}
continue
}
if err := fa.ReadRemainder(); err != nil {
log.Printf("file %s reading FAIL, recheck it", fa.Filename)
fa.FileReopen()
}
}
// CREATE event
if 1 == event.Op {
fmt.Printf("fa %s, watch %s receive event CREATE\n", fa.Filename, event.Name)
fa.FileReopen()
}
// REMOVE/RENAME event
if 4 == event.Op || 8 == event.Op {
fmt.Printf("fa %s, watch %s receive event REMOVE|RENAME\n", fa.Filename, event.Name)
fa.FileClose()
}
// CHMOD event
if 16 == event.Op {
fmt.Printf("fa %s, watch %s receive event CHMOD\n", fa.Filename, event.Name)
}
}
case err := <-watcher.Errors:
log.Printf("%s receive error %s", fa.Filename, err.Error())
case <-ticker.C:
fa.Timeup()
default:
time.Sleep(time.Millisecond * 100)
}
}
wg.Done()
fmt.Printf("agent for %s is exiting...\n", fa.Filename)
}
/*
* FileOpen - open file while file agent initializing
*
* RECEIVER: *FileAgent
*
* PARAMS:
* No paramter
*
* RETURNS:
* nil, if succeed
* error, if fail
*/
func (fa *FileAgent) FileOpen() error {
// close old file
if fa.File != nil {
if err := fa.File.Close(); err != nil {
log.Printf("file closing FAIL: %s", err.Error())
}
}
fa.File = nil
fa.FileInfo = nil
// open new file
filename := fa.Filename
file, err := os.Open(filename)
if err != nil {
log.Printf("file %s open FAIL: %s", fa.Filename, err.Error())
return err
}
fileinfo, err := file.Stat()
if err != nil {
log.Printf("file %s stat FAIL: %s", fa.Filename, err.Error())
return err
}
fmt.Printf("file %s is open\n", fa.Filename)
fa.File = file
fa.FileInfo = fileinfo
fa.LastOffset = 0
// seek the cursor to the end of new file
_, err = fa.File.Seek(fa.FileInfo.Size(), os.SEEK_SET)
if err != nil {
log.Printf("seek file %s FAIL: %s", fa.Filename, err.Error())
}
fa.LastOffset += fa.FileInfo.Size()
// set timestamp
now := time.Now()
minute := now.Format("200601021504")
tsNow := now.Unix()
tsStart := tsNow
start, err := time.ParseInLocation("20060102150405", minute+"00", now.Location())
if err != nil {
log.Printf("timestamp setting FAIL: %s", err.Error())
} else {
tsStart = start.Unix()
}
for _, task := range fa.Tasks {
task.TsStart = tsStart
task.TsEnd = tsStart + task.Step - 1
task.TsUpdate = tsNow
task.ValueCnt = 0
task.ValueMax = 0
task.ValueMin = 1 << 32
task.ValueSum = 0
}
return nil
}
/*
* FileInfoUpdate - stat file when WRITE
*
* RECEIVER: *FileAgent
*
* PARAMS:
* No paramter
*
* RETURNS:
* nil, if succeed
* error, if fail
*/
func (fa *FileAgent) FileInfoUpdate() error {
fileinfo, err := fa.File.Stat()
if err != nil {
log.Printf("file %s stat FAIL: %s", fa.Filename, err.Error())
fa.UnchangeTime += 1
return err
}
fa.FileInfo = fileinfo
fa.UnchangeTime = 0
return nil
}
/*
* FileClose - close file when REMOVE/RENAME
*
* RECEIVER: *FileAgent
*
* PARAMS:
* No paramter
*
* RETURNS:
* nil, if succeed
* error, if fail
*/
func (fa *FileAgent) FileClose() error {
// close old file
if fa.File != nil {
if err := fa.File.Close(); err != nil {
log.Printf("file closing FAIL: %s", err.Error())
return err
}
}
fa.File = nil
fa.FileInfo = nil
fa.LastOffset = 0
fa.UnchangeTime = 0
for _, task := range fa.Tasks {
task.TsStart = 0
task.TsEnd = 0
task.TsUpdate = 0
task.ValueCnt = 0
task.ValueMax = 0
task.ValueMin = 1 << 32
task.ValueSum = 0
}
return nil
}
/*
* FileReopen - reopen file when CREATE/ERROR
*
* RECEIVER: *FileAgent
*
* PARAMS:
* No paramter
*
* RETURNS:
* nil: succeed
* error: fail
*/
func (fa *FileAgent) FileReopen() error {
// close old file
if fa.File != nil {
if err := fa.File.Close(); err != nil {
log.Printf("file closing FAIL: %s", err.Error())
}
}
fa.File = nil
fa.FileInfo = nil
// open new file
filename := fa.Filename
file, err := os.Open(filename)
if err != nil {
log.Printf("file %s opening FAIL: %s", fa.Filename, err.Error())
return err
}
fileinfo, err := file.Stat()
if err != nil {
log.Printf("file %s stat FAIL: %s", fa.Filename, err.Error())
return err
}
log.Printf("file %s recheck ok, it is a new file", fa.Filename)
fa.File = file
fa.FileInfo = fileinfo
fa.LastOffset = 0
// seek the cursor to the start of new file
_, err = fa.File.Seek(0, os.SEEK_SET)
if err != nil {
log.Printf("seek file %s FAIL: %s", fa.Filename, err.Error())
}
// set timestamp
now := time.Now()
minute := now.Format("200601021504")
tsNow := now.Unix()
tsStart := tsNow
start, err := time.ParseInLocation("20060102150405", minute+"00", now.Location())
if err != nil {
log.Printf("timestamp setting FAIL: %s", err.Error())
} else {
tsStart = start.Unix()
}
for _, task := range fa.Tasks {
task.TsStart = tsStart
task.TsEnd = tsStart + task.Step - 1
task.TsUpdate = tsNow
task.ValueCnt = 0
task.ValueMax = 0
task.ValueMin = 1 << 32
task.ValueSum = 0
}
return nil
}
/*
* FileRecheck - recheck the file for file agent
*
* RECEIVER: *FileAgent
*
* PARAMS:
* No paramter
*
* RETURNS:
* nil, if succeed
* error, if fail
*/
func (fa *FileAgent) FileRecheck() error {
filename := fa.Filename
file, err := os.Open(filename)
if err != nil {
log.Printf("file %s opening FAIL: %v", fa.Filename, err)
fa.UnchangeTime = 0
return err
}
fileinfo, err := file.Stat()
if err != nil {
log.Printf("file %s stat FAIL: %v", fa.Filename, err)
fa.UnchangeTime = 0
return err
}
isSameFile := os.SameFile(fa.FileInfo, fileinfo)
if !isSameFile {
log.Printf("file %s recheck, it is a new file", fa.Filename)
if fa.File != nil {
if err := fa.File.Close(); err != nil {
log.Printf("old file closing FAIL: %v", err)
}
}
fa.File = file
fa.FileInfo = fileinfo
fa.LastOffset = 0
fa.UnchangeTime = 0
// seek the cursor to the end of new file
offset, err := fa.File.Seek(fa.FileInfo.Size(), os.SEEK_SET)
if err != nil {
log.Printf("seek file %s FAIL: %v", fa.Filename, err)
}
log.Printf("seek file %s to %d", fa.Filename, offset)
fa.LastOffset += fa.FileInfo.Size()
now := time.Now()
minute := now.Format("200601021504")
tsNow := now.Unix()
tsStart := tsNow
start, err := time.ParseInLocation("20060102150405", minute+"00", now.Location())
if err != nil {
log.Printf("timestamp setting FAIL: %v", err)
} else {
tsStart = start.Unix()
}
for _, task := range fa.Tasks {
task.TsStart = tsStart
task.TsEnd = tsStart + task.Step - 1
task.TsUpdate = tsNow
task.ValueCnt = 0
task.ValueMax = 0
task.ValueMin = 1 << 32
task.ValueSum = 0
}
return nil
} else {
fa.UnchangeTime = 0
return nil
}
}
/*
* IsChanged - check the change of log file
*
* RECEIVER: *FileAgent
*
* PARAMS:
* No paramter
*
* RETURNS:
* - true: if change
* - false: if not change
*/
func (fa *FileAgent) IsChanged() bool {
lastMode := fa.FileInfo.Mode()
lastSize := fa.FileInfo.Size()
lastModTime := fa.FileInfo.ModTime().Unix()
fileinfo, err := fa.File.Stat()
if err != nil {
log.Printf("file %s stat FAIL: %v", err)
fa.UnchangeTime += 1
return false
}
thisMode := fileinfo.Mode()
thisSize := fileinfo.Size()
thisModTime := fileinfo.ModTime().Unix()
thisTailable := fileinfo.Mode().IsRegular()
if lastMode == thisMode &&
(!thisTailable || lastSize == thisSize) &&
lastModTime == thisModTime {
fa.UnchangeTime += 1
return false
}
// replace the FileInfo for reading the new content
fa.UnchangeTime = 0
fa.FileInfo = fileinfo
return true
}