Automatically uploading files

Quick post today. I was working on a website where I have a live server running the code on another machine. I wanted to write a quick script that would copy any files I changed to the remote machine. This is something you can do automatically in most IDEs, but I wanted something both a bit lighter weight and to have the excuse to write something myself.

Basically, I’m going to wrap fsnotify with a quick queue that can keep track of files as they’re changed and upload them in order.

First, the functionality that can run an arbitrary command (at least one that returns a list of filenames) and put any files found into a queue (we’ll see why in a moment):

sync_queue = queue.Queue()

def sync_command(command):
    process = subprocess.Popen(command, shell = True, stdout = subprocess.PIPE)
    for line in process.stdout:
        for file in line.decode().strip().split():
            sync_queue.put(file)

And then the other half–a thread that can take those files off the queue and automatically upload them to a remote server:

def do_sync():
    while True:
        path = sync_queue.get()
        local_path = path.replace(local_directory, '').lstrip('/')
        remote_path = remote_directory.rstrip('/') + '/' + local_path

        print('[{} remaining] {} ... '.format(sync_queue.qsize(), local_path), end = '')
        sys.stdout.flush()

        subprocess.check_call('scp "{local_path}" "{remote_host}:{remote_path}"'.format(
            local_path = local_path,
            remote_host = remote_host,
            remote_path = remote_path
        ), shell = True, stdout = subprocess.PIPE, stderr = subprocess.STDOUT)

        print('done')

# Start up the sync thread
sync_thread = threading.Thread(target = do_sync)
sync_thread.daemon = True
sync_thread.start()

And that’s all we need. We can run a trio of commands to automatically sync any changes that we’ve made on a git branch plus any we make going forward:

# Sync any differences on the current branch (first changed, then new files)
sync_command('git diff --name-only master')
sync_command('git ls-files --others --exclude-standard')

# Sync any changes to files as they happen
sync_command('fswatch -r -e ".git" .')

And that’s it. fswatch really does most of the work, but it’s a nice wrapper that will continually sync files until you tell it to quit.

It’s useful enough that I already put it in my dotfiles repo: sync.

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