/
journalbeat.go
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/
journalbeat.go
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// Copyright 2017 Marcus Heese
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package beater
import (
"encoding/json"
"fmt"
"io/ioutil"
"os"
"sync"
"time"
"github.com/coreos/go-systemd/sdjournal"
"github.com/elastic/beats/libbeat/beat"
"github.com/elastic/beats/libbeat/common"
"github.com/elastic/beats/libbeat/logp"
"github.com/elastic/beats/libbeat/publisher"
"github.com/mheese/journalbeat/config"
"github.com/mheese/journalbeat/journal"
)
// Journalbeat is the main Journalbeat struct
type Journalbeat struct {
done chan struct{}
config config.Config
client publisher.Client
journal *sdjournal.Journal
cursorChan chan string
pending, completed chan *eventReference
wg sync.WaitGroup
}
func (jb *Journalbeat) initJournal() error {
var err error
seekToHelper := func(position string, err error) error {
if err == nil {
logp.Info("Seek to %s successful", position)
} else {
logp.Warn("Could not seek to %s: %v", position, err)
}
return err
}
// connect to the Systemd Journal
switch len(jb.config.JournalPaths) {
case 0:
if jb.journal, err = sdjournal.NewJournal(); err != nil {
return err
}
case 1:
fi, err := os.Stat(jb.config.JournalPaths[0])
if err != nil {
return err
}
if fi.IsDir() {
if jb.journal, err = sdjournal.NewJournalFromDir(jb.config.JournalPaths[0]); err != nil {
return err
}
} else {
if jb.journal, err = sdjournal.NewJournalFromFiles(jb.config.JournalPaths...); err != nil {
return err
}
}
default:
if jb.journal, err = sdjournal.NewJournalFromFiles(jb.config.JournalPaths...); err != nil {
return err
}
}
// add specific units to monitor if any
if err = jb.addUnits(); err != nil {
return err
}
// add specific patterns to monitor if any
for _, pattern := range jb.config.MatchPatterns {
err = jb.journal.AddMatch(pattern)
if err == nil {
err = jb.journal.AddDisjunction()
}
if err != nil {
return fmt.Errorf("Filtering pattern %s failed: %v", pattern, err)
}
}
// add kernel logs
if err = jb.addKernel(); err != nil {
return err
}
// add syslog identifiers to monitor if any
if err = jb.addSyslogIdentifiers(); err != nil {
return err
}
// seek position
position := jb.config.SeekPosition
// try seekToCursor first, if that is requested
if position == config.SeekPositionCursor {
if cursor, err := ioutil.ReadFile(jb.config.CursorStateFile); err != nil {
logp.Warn("Could not seek to cursor: reading cursor state file failed: %v", err)
} else {
// try to seek to cursor and if successful return
if err = seekToHelper(config.SeekPositionCursor, jb.journal.SeekCursor(string(cursor))); err == nil {
return nil
}
}
if jb.config.CursorSeekFallback == config.SeekPositionDefault {
return err
}
position = jb.config.CursorSeekFallback
}
switch position {
case config.SeekPositionHead:
err = seekToHelper(config.SeekPositionHead, jb.journal.SeekHead())
case config.SeekPositionTail:
err = seekToHelper(config.SeekPositionTail, jb.journal.SeekTail())
}
if err != nil {
return fmt.Errorf("Seeking to a good position in journal failed: %v", err)
}
return nil
}
// Add syslog identifiers to monitor
func (jb *Journalbeat) addSyslogIdentifiers() error {
var err error
for _, identifier := range jb.config.Identifiers {
if err = jb.journal.AddMatch(sdjournal.SD_JOURNAL_FIELD_SYSLOG_IDENTIFIER + "=" + identifier); err != nil {
return fmt.Errorf("Filtering syslog identifier %s failed: %v", identifier, err)
}
if err = jb.journal.AddDisjunction(); err != nil {
return fmt.Errorf("Filtering syslog identifier %s failed: %v", identifier, err)
}
}
return nil
}
func (jb *Journalbeat) publishPending() error {
refs := []*eventReference{}
pending := map[string]common.MapStr{}
file, err := os.Open(jb.config.PendingQueue.File)
if err != nil {
return err
}
defer file.Close()
if err = json.NewDecoder(file).Decode(&pending); err != nil {
return err
}
logp.Info("Loaded %d events, trying to publish", len(pending))
for cursor, event := range pending {
// We need to convert the timestamp back to the correct type before trying to publish
timestamp, _ := time.Parse(time.RFC3339, event["@timestamp"].(string))
event["@timestamp"] = common.Time(timestamp)
ref := &eventReference{cursor, event}
jb.pending <- ref
refs = append(refs, ref)
}
for _, ref := range refs {
select {
case <-jb.done:
return nil
default:
// we need to clone to avoid races since map is a pointer...
jb.client.PublishEvent(ref.body.Clone(), publisher.Signal(&eventSignal{ref, jb.completed}), publisher.Guaranteed)
}
}
return nil
}
// New creates beater
func New(b *beat.Beat, cfg *common.Config) (beat.Beater, error) {
config := config.DefaultConfig
var err error
if err = cfg.Unpack(&config); err != nil {
return nil, fmt.Errorf("Error reading config file: %v", err)
}
jb := &Journalbeat{
config: config,
done: make(chan struct{}),
cursorChan: make(chan string),
pending: make(chan *eventReference),
completed: make(chan *eventReference, config.PendingQueue.CompletedQueueSize),
}
if err = jb.initJournal(); err != nil {
logp.Err("Failed to connect to the Systemd Journal: %v", err)
return nil, err
}
jb.client = b.Publisher.Connect()
return jb, nil
}
// Run is the main event loop: read from journald and pass it to Publish
func (jb *Journalbeat) Run(b *beat.Beat) error {
publishedChan := make(chan bool, 1)
logp.Info("Journalbeat is running!")
defer func() {
_ = jb.client.Close()
_ = jb.journal.Close()
close(jb.cursorChan)
close(jb.completed)
close(jb.pending)
jb.wg.Wait()
}()
go jb.managePendingQueueLoop()
if jb.config.WriteCursorState {
go jb.writeCursorLoop()
}
// load the previously saved queue of unsent events and try to publish them if any
if err := jb.publishPending(); err != nil {
logp.Warn("could not read the pending queue: %s", err)
}
for rawEvent := range journal.Follow(jb.journal, jb.done) {
//convert sdjournal.JournalEntry to common.MapStr
event := MapStrFromJournalEntry(
rawEvent,
jb.config.CleanFieldNames,
jb.config.ConvertToNumbers,
jb.config.MoveMetadataLocation,
jb.config.ParsePriority,
jb.config.ParseSyslogFacility)
if _, ok := event["type"].(string); !ok {
event["type"] = jb.config.DefaultType
}
event["@timestamp"] = common.Time(time.Unix(0, int64(rawEvent.RealtimeTimestamp)*1000))
// add _REALTIME_TIMESTAMP until https://github.com/elastic/elasticsearch/issues/12829 is closed
event["@realtime_timestamp"] = int64(rawEvent.RealtimeTimestamp)
ref := &eventReference{rawEvent.Cursor, event}
select {
case <-jb.done:
return nil
case publishedChan <- jb.client.PublishEvent(event, publisher.Signal(&eventSignal{ref, jb.completed}), publisher.Guaranteed):
if published := <-publishedChan; published {
jb.pending <- ref
// save cursor
if jb.config.WriteCursorState {
jb.cursorChan <- rawEvent.Cursor
}
}
}
}
return nil
}
// Stop stops Journalbeat execution
func (jb *Journalbeat) Stop() {
logp.Info("Stopping Journalbeat")
close(jb.done)
}