46893e84c3
This splits the recursive watching bit of the file file resource into it's own package. This also de-duplicates the configwatch code and puts it into the same package. With these bits refactored, it was also easier to clean up the error code in main.
135 lines
3.3 KiB
Go
135 lines
3.3 KiB
Go
// Mgmt
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// Copyright (C) 2013-2016+ James Shubin and the project contributors
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// Written by James Shubin <james@shubin.ca> and the project contributors
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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package recwatch
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import (
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"log"
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"sync"
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"github.com/purpleidea/mgmt/global"
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)
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// ConfigWatcher returns events on a channel anytime one of its files events.
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type ConfigWatcher struct {
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ch chan string
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wg sync.WaitGroup
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closechan chan struct{}
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errorchan chan error
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}
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// NewConfigWatcher creates a new ConfigWatcher struct.
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func NewConfigWatcher() *ConfigWatcher {
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return &ConfigWatcher{
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ch: make(chan string),
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closechan: make(chan struct{}),
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errorchan: make(chan error),
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}
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}
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// Add new file paths to watch for events on.
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func (obj *ConfigWatcher) Add(file ...string) {
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if len(file) == 0 {
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return
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}
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if len(file) > 1 {
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for _, f := range file { // add all the files...
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obj.Add(f) // recurse
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}
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return
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}
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// otherwise, add the one file passed in...
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obj.wg.Add(1)
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go func() {
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defer obj.wg.Done()
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ch := ConfigWatch(file[0])
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for {
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select {
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case e := <-ch:
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if e != nil {
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obj.errorchan <- e
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return
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}
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obj.ch <- file[0]
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continue
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case <-obj.closechan:
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return
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}
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}
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}()
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}
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// Error returns a channel of errors that notifies us of permanent issues.
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func (obj *ConfigWatcher) Error() <-chan error {
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return obj.errorchan
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}
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// Events returns a channel to listen on for file events. It closes when it is
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// emptied after the Close() method is called. You can test for closure with the
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// f, more := <-obj.Events() pattern.
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func (obj *ConfigWatcher) Events() chan string {
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return obj.ch
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}
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// Close shuts down the ConfigWatcher object. It closes the Events channel after
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// all the currently pending events have been emptied.
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func (obj *ConfigWatcher) Close() {
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if obj.ch == nil {
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return
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}
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close(obj.closechan)
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obj.wg.Wait() // wait until everyone is done sending on obj.ch
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//obj.ch <- "" // send finished message
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close(obj.ch)
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obj.ch = nil
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close(obj.errorchan)
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}
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// ConfigWatch writes on the channel every time an event is seen for the path.
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func ConfigWatch(file string) chan error {
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ch := make(chan error)
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go func() {
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recWatcher, err := NewRecWatcher(file, false)
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if err != nil {
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ch <- err
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close(ch)
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return
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}
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defer recWatcher.Close()
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for {
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if global.DEBUG {
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log.Printf("Watching: %v", file)
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}
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select {
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case event, ok := <-recWatcher.Events():
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if !ok { // channel is closed
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close(ch)
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return
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}
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if err := event.Error; err != nil {
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ch <- err
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close(ch)
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return
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}
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ch <- nil // send event!
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}
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}
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//close(ch)
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}()
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return ch
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}
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