70 lines
1.8 KiB
Go
70 lines
1.8 KiB
Go
// Copyright 2013 Prometheus Team
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package config
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import (
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"github.com/golang/glog"
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"github.com/howeyc/fsnotify"
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)
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type ReloadCallback func(*Config)
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type Watcher interface {
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Watch(c ReloadCallback)
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}
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type fileWatcher struct {
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fileName string
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}
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func NewFileWatcher(fileName string) *fileWatcher {
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return &fileWatcher{
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fileName: fileName,
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}
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}
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func (w *fileWatcher) Watch(cb ReloadCallback) {
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watcher, err := fsnotify.NewWatcher()
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if err != nil {
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glog.Fatal(err)
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}
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err = watcher.WatchFlags(w.fileName, fsnotify.FSN_MODIFY)
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if err != nil {
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glog.Fatal(err)
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}
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for {
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select {
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case ev := <-watcher.Event:
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glog.Infof("Config file changed (%s), attempting reload", ev)
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conf, err := LoadFromFile(w.fileName)
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if err != nil {
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glog.Error("Error loading new config: ", err)
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failedConfigReloads.Inc()
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} else {
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cb(&conf)
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glog.Info("Config reloaded successfully")
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configReloads.Inc()
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}
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// Re-add the file watcher since it can get lost on some changes. E.g.
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// saving a file with vim results in a RENAME-MODIFY-DELETE event
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// sequence, after which the newly written file is no longer watched.
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err = watcher.WatchFlags(w.fileName, fsnotify.FSN_MODIFY)
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case err := <-watcher.Error:
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glog.Error("Error watching config: ", err)
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}
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}
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}
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