File system notifications for Go

Cross platform: Windows, Linux, BSD and OS X.

Moving Notice

There is a fork being actively developed with a new API in preparation for the Go Standard Library: github.com/go-fsnotify/fsnotify

Example:

package main
import (
"log""github.com/howeyc/fsnotify"
)
funcmain() {
watcher, err:=fsnotify.NewWatcher()
iferr!=nil {
log.Fatal(err)
}
done:=make(chanbool)
// Process eventsgofunc() {
for {
select {
caseev:=<-watcher.Event:
log.Println("event:", ev)
caseerr:=<-watcher.Error:
log.Println("error:", err)
}
}
}()
err=watcher.Watch("testDir")
iferr!=nil {
log.Fatal(err)
}
<-done/* ... do stuff ... */watcher.Close()
}

For each event:

• Name
• IsCreate()
• IsDelete()
• IsModify()
• IsRename()

FAQ

When a file is moved to another directory is it still being watched?

No (it shouldn't be, unless you are watching where it was moved to).

When I watch a directory, are all subdirectories watched as well?

No, you must add watches for any directory you want to watch (a recursive watcher is in the works #56).

Do I have to watch the Error and Event channels in a separate goroutine?

As of now, yes. Looking into making this single-thread friendly (see #7)

Why am I receiving multiple events for the same file on OS X?

Spotlight indexing on OS X can result in multiple events (see #62). A temporary workaround is to add your folder(s) to the Spotlight Privacy settings until we have a native FSEvents implementation (see #54).

How many files can be watched at once?

There are OS-specific limits as to how many watches can be created:

• Linux: /proc/sys/fs/inotify/max_user_watches contains the limit, reaching this limit results in a "no space left on device" error.
• BSD / OSX: sysctl variables "kern.maxfiles" and "kern.maxfilesperproc", reaching these limits results in a "too many open files" error.