4.5 KiB
watcher
watcher
is a Go package for watching for files or directory changes (recursively or non recursively) without using filesystem events, which allows it to work cross platform consistently.
watcher
watches for changes and notifies over channels either anytime an event or an error has occurred.
Events contain the os.FileInfo
of the file or directory that the event is based on and the type of event and file or directory path.
Installation
Features
Example
Contributing
Watcher Command
Update
Event.Path for Rename and Move events is now returned in the format of fromPath -> toPath
Chmod event is not supported under windows.
Installation
go get -u github.com/radovskyb/watcher/...
Features
- Customizable polling interval.
- Filter Events.
- Watch folders recursively or non-recursively.
- Choose to ignore hidden files.
- Choose to ignore specified files and folders.
- Notifies the
os.FileInfo
of the file that the event is based on. e.gName
,ModTime
,IsDir
, etc. - Notifies the full path of the file that the event is based on or the old and new paths if the event was a
Rename
orMove
event. - Limit amount of events that can be received per watching cycle.
- List the files being watched.
- Trigger custom events.
Todo
- Write more tests.
- Write benchmarks.
Example
package main
import (
"fmt"
"log"
"time"
"github.com/radovskyb/watcher"
)
func main() {
w := watcher.New()
// SetMaxEvents to 1 to allow at most 1 event's to be received
// on the Event channel per watching cycle.
//
// If SetMaxEvents is not set, the default is to send all events.
w.SetMaxEvents(1)
// Only notify rename and move events.
w.FilterOps(watcher.Rename, watcher.Move)
go func() {
for {
select {
case event := <-w.Event:
fmt.Println(event) // Print the event's info.
case err := <-w.Error:
log.Fatalln(err)
case <-w.Closed:
return
}
}
}()
// Watch this folder for changes.
if err := w.Add("."); err != nil {
log.Fatalln(err)
}
// Watch test_folder recursively for changes.
if err := w.AddRecursive("../test_folder"); err != nil {
log.Fatalln(err)
}
// Print a list of all of the files and folders currently
// being watched and their paths.
for path, f := range w.WatchedFiles() {
fmt.Printf("%s: %s\n", path, f.Name())
}
fmt.Println()
// Trigger 2 events after watcher started.
go func() {
w.Wait()
w.TriggerEvent(watcher.Create, nil)
w.TriggerEvent(watcher.Remove, nil)
}()
// Start the watching process - it'll check for changes every 100ms.
if err := w.Start(time.Millisecond * 100); err != nil {
log.Fatalln(err)
}
}
Contributing
If you would ike to contribute, simply submit a pull request.
Command
watcher
comes with a simple command which is installed when using the go get
command from above.
Usage
Usage of watcher:
-cmd string
command to run when an event occurs
-dotfiles
watch dot files (default true)
-interval string
watcher poll interval (default "100ms")
-keepalive
keep alive when a cmd returns code != 0
-list
list watched files on start
-pipe
pipe event's info to command's stdin
-recursive
watch folders recursively (default true)
-startcmd
run the command when watcher starts
All of the flags are optional and watcher can also be called by itself:
watcher
(watches the current directory recursively for changes and notifies any events that occur.)
A more elaborate example using the watcher
command:
watcher -dotfiles=false -recursive=false -cmd="./myscript" main.go ../
In this example, watcher
will ignore dot files and folders and won't watch any of the specified folders recursively. It will also run the script ./myscript
anytime an event occurs while watching main.go
or any files or folders in the previous directory (../
).
Using the pipe
and cmd
flags together will send the event's info to the command's stdin when changes are detected.
First create a file called script.py
with the following contents:
import sys
for line in sys.stdin:
print (line + " - python")
Next, start watcher with the pipe
and cmd
flags enabled:
watcher -cmd="python script.py" -pipe=true
Now when changes are detected, the event's info will be output from the running python script.