122 lines
2.4 KiB
Go
122 lines
2.4 KiB
Go
// Licensed to Elasticsearch B.V. under one or more contributor
|
|
// license agreements. See the NOTICE file distributed with
|
|
// this work for additional information regarding copyright
|
|
// ownership. Elasticsearch B.V. licenses this file to you 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 watcher
|
|
|
|
import (
|
|
"hash/fnv"
|
|
"io/ioutil"
|
|
"os"
|
|
"time"
|
|
|
|
"github.com/elastic/beats/libbeat/logp"
|
|
)
|
|
|
|
type Watch interface {
|
|
Stop()
|
|
}
|
|
|
|
type filePoller struct {
|
|
done chan struct{}
|
|
}
|
|
|
|
type fileChangeTester struct {
|
|
path string
|
|
sz int
|
|
hash uint64
|
|
stat os.FileInfo
|
|
}
|
|
|
|
func NewFilePoller(
|
|
path string,
|
|
poll time.Duration,
|
|
do func([]byte),
|
|
) (Watch, error) {
|
|
fw := &filePoller{
|
|
done: make(chan struct{}),
|
|
}
|
|
|
|
tester := &fileChangeTester{path: path, sz: -1}
|
|
if content, changed := tester.check(); changed {
|
|
do(content)
|
|
}
|
|
|
|
go func() {
|
|
ticker := time.NewTicker(poll)
|
|
defer ticker.Stop()
|
|
|
|
for {
|
|
if content, changed := tester.check(); changed {
|
|
do(content)
|
|
}
|
|
|
|
select {
|
|
case <-fw.done:
|
|
return
|
|
case <-ticker.C:
|
|
}
|
|
}
|
|
}()
|
|
|
|
return fw, nil
|
|
}
|
|
|
|
func (f *filePoller) Stop() {
|
|
close(f.done)
|
|
}
|
|
|
|
func (w *fileChangeTester) check() ([]byte, bool) {
|
|
f, err := os.Open(w.path)
|
|
if err != nil {
|
|
logp.Info("Failed to load file: %v", err)
|
|
return nil, false
|
|
}
|
|
defer f.Close()
|
|
|
|
stat, err := f.Stat()
|
|
if err != nil {
|
|
logp.Info("Reading file '%v' stat failed with: %v", w.path, err)
|
|
return nil, false
|
|
}
|
|
|
|
if w.stat != nil {
|
|
if stat.Size() == w.stat.Size() && !stat.ModTime().After(w.stat.ModTime()) {
|
|
return nil, false
|
|
}
|
|
}
|
|
|
|
content, err := ioutil.ReadAll(f)
|
|
if err != nil {
|
|
logp.Info("Reading file '%v' failed with: %v", w.path, err)
|
|
return nil, false
|
|
}
|
|
|
|
var hash uint64
|
|
if len(content) != 0 || w.sz == 0 {
|
|
hasher := fnv.New64a()
|
|
hasher.Write(content)
|
|
hash = hasher.Sum64()
|
|
if w.hash == hash {
|
|
return nil, false
|
|
}
|
|
}
|
|
|
|
w.hash = hash
|
|
w.stat = stat
|
|
w.sz = len(content)
|
|
return content, true
|
|
}
|