split watchmedo logic into _watchmedo.py (yaml and argh independent)

src/watchdog/_watchmedo.py

@@ -0,0 +1,249 @@
+# coding: utf-8
+#
+# Copyright 2011 Yesudeep Mangalapilly <yesudeep@gmail.com>
+# Copyright 2012 Google, Inc & contributors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+:module: watchdog.watchmedo
+:author: yesudeep@google.com (Yesudeep Mangalapilly)
+:author: contact@tiger-222.fr (Mickaël Schoentgen)
+:synopsis: ``watchmedo`` shell script utility.
+"""
+
+import os
+import os.path
+import sys
+import time
+import logging
+
+from watchdog.utils import WatchdogShutdown, load_class
+
+
+logging.basicConfig(level=logging.INFO)
+
+CONFIG_KEY_TRICKS = 'tricks'
+CONFIG_KEY_PYTHON_PATH = 'python-path'
+
+
+def path_split(pathname_spec, separator=os.pathsep):
+    """
+    Splits a pathname specification separated by an OS-dependent separator.
+
+    :param pathname_spec:
+        The pathname specification.
+    :param separator:
+        (OS Dependent) `:` on Unix and `;` on Windows or user-specified.
+    """
+    return list(pathname_spec.split(separator))
+
+
+def add_to_sys_path(pathnames, index=0):
+    """
+    Adds specified paths at specified index into the sys.path list.
+
+    :param paths:
+        A list of paths to add to the sys.path
+    :param index:
+        (Default 0) The index in the sys.path list where the paths will be
+        added.
+    """
+    for pathname in pathnames[::-1]:
+        sys.path.insert(index, pathname)
+
+
+def parse_patterns(patterns_spec, ignore_patterns_spec, separator=';'):
+    """
+    Parses pattern argument specs and returns a two-tuple of
+    (patterns, ignore_patterns).
+    """
+    patterns = patterns_spec.split(separator)
+    ignore_patterns = ignore_patterns_spec.split(separator)
+    if ignore_patterns == ['']:
+        ignore_patterns = []
+    return (patterns, ignore_patterns)
+
+
+def observe_with(observer, event_handler, pathnames, recursive):
+    """
+    Single observer thread with a scheduled path and event handler.
+
+    :param observer:
+        The observer thread.
+    :param event_handler:
+        Event handler which will be called in response to file system events.
+    :param pathnames:
+        A list of pathnames to monitor.
+    :param recursive:
+        ``True`` if recursive; ``False`` otherwise.
+    """
+    for pathname in set(pathnames):
+        observer.schedule(event_handler, pathname, recursive)
+    observer.start()
+    try:
+        while True:
+            time.sleep(1)
+    except WatchdogShutdown:
+        observer.stop()
+    observer.join()
+
+
+def schedule_tricks(observer, tricks, pathname, recursive):
+    """
+    Schedules tricks with the specified observer and for the given watch
+    path.
+
+    :param observer:
+        The observer thread into which to schedule the trick and watch.
+    :param tricks:
+        A list of tricks.
+    :param pathname:
+        A path name which should be watched.
+    :param recursive:
+        ``True`` if recursive; ``False`` otherwise.
+    """
+    for trick in tricks:
+        for name, value in list(trick.items()):
+            TrickClass = load_class(name)
+            handler = TrickClass(**value)
+            trick_pathname = getattr(handler, 'source_directory', None) or pathname
+            observer.schedule(handler, trick_pathname, recursive)
+
+
+def log(args):
+    """
+    Subcommand to log file system events to the console.
+
+    :param args:
+        Command line argument options.
+    """
+    from watchdog.utils import echo
+    from watchdog.tricks import LoggerTrick
+
+    if args.trace:
+        echo.echo_class(LoggerTrick)
+
+    patterns, ignore_patterns =\
+        parse_patterns(args.patterns, args.ignore_patterns)
+    handler = LoggerTrick(patterns=patterns,
+                          ignore_patterns=ignore_patterns,
+                          ignore_directories=args.ignore_directories)
+    if args.debug_force_polling:
+        from watchdog.observers.polling import PollingObserver as Observer
+    elif args.debug_force_kqueue:
+        from watchdog.observers.kqueue import KqueueObserver as Observer
+    elif args.debug_force_winapi_async:
+        from watchdog.observers.read_directory_changes_async import\
+            WindowsApiAsyncObserver as Observer
+    elif args.debug_force_winapi:
+        from watchdog.observers.read_directory_changes import\
+            WindowsApiObserver as Observer
+    elif args.debug_force_inotify:
+        from watchdog.observers.inotify import InotifyObserver as Observer
+    elif args.debug_force_fsevents:
+        from watchdog.observers.fsevents import FSEventsObserver as Observer
+    else:
+        # Automatically picks the most appropriate observer for the platform
+        # on which it is running.
+        from watchdog.observers import Observer
+    observer = Observer(timeout=args.timeout)
+    observe_with(observer, handler, args.directories, args.recursive)
+
+
+def shell_command(args):
+    """
+    Subcommand to execute shell commands in response to file system events.
+
+    :param args:
+        Command line argument options.
+    """
+    from watchdog.tricks import ShellCommandTrick
+
+    if not args.command:
+        args.command = None
+
+    if args.debug_force_polling:
+        from watchdog.observers.polling import PollingObserver as Observer
+    else:
+        from watchdog.observers import Observer
+
+    patterns, ignore_patterns = parse_patterns(args.patterns,
+                                               args.ignore_patterns)
+    handler = ShellCommandTrick(shell_command=args.command,
+                                patterns=patterns,
+                                ignore_patterns=ignore_patterns,
+                                ignore_directories=args.ignore_directories,
+                                wait_for_process=args.wait_for_process,
+                                drop_during_process=args.drop_during_process)
+    observer = Observer(timeout=args.timeout)
+    observe_with(observer, handler, args.directories, args.recursive)
+
+
+def auto_restart(args):
+    """
+    Subcommand to start a long-running subprocess and restart it
+    on matched events.
+
+    :param args:
+        Command line argument options.
+    """
+
+    if args.debug_force_polling:
+        from watchdog.observers.polling import PollingObserver as Observer
+    else:
+        from watchdog.observers import Observer
+
+    from watchdog.tricks import AutoRestartTrick
+    import signal
+
+    if not args.directories:
+        args.directories = ['.']
+
+    # Allow either signal name or number.
+    if args.signal.startswith("SIG"):
+        stop_signal = getattr(signal, args.signal)
+    else:
+        stop_signal = int(args.signal)
+
+    # Handle termination signals by raising a semantic exception which will
+    # allow us to gracefully unwind and stop the observer
+    termination_signals = {signal.SIGTERM, signal.SIGINT}
+
+    def handler_termination_signal(_signum, _frame):
+        # Neuter all signals so that we don't attempt a double shutdown
+        for signum in termination_signals:
+            signal.signal(signum, signal.SIG_IGN)
+        raise WatchdogShutdown
+
+    for signum in termination_signals:
+        signal.signal(signum, handler_termination_signal)
+
+    patterns, ignore_patterns = parse_patterns(args.patterns,
+                                               args.ignore_patterns)
+    command = [args.command]
+    command.extend(args.command_args)
+    handler = AutoRestartTrick(command=command,
+                               patterns=patterns,
+                               ignore_patterns=ignore_patterns,
+                               ignore_directories=args.ignore_directories,
+                               stop_signal=stop_signal,
+                               kill_after=args.kill_after)
+    handler.start()
+    observer = Observer(timeout=args.timeout)
+    try:
+        observe_with(observer, handler, args.directories, args.recursive)
+    except WatchdogShutdown:
+        pass
+    finally:
+        handler.stop()