hupper 1.0

Integrated process monitor for developing and reloading daemons.

hupper is an integrated process monitor that will track changes to any imported Python files in sys.modules as well as custom paths. When files are changed the process is restarted.

Command-line Usage

Hupper can load any Python code similar to python -m <module> by using the hupper -m <module> program.

$ hupper -m myapp
Starting monitor for PID 23982.

API Usage

Start by defining an entry point for your process. This must be an importable path in string format. For example, myapp.scripts.serve.main.

# myapp/scripts/serve.py

import sys
import hupper
import waitress

def wsgi_app(environ, start_response):
    start_response('200 OK', [('Content-Type', 'text/plain'])
    yield [b'hello']

def main(args=sys.argv[1:]):
    if '--reload' in args:
        # start_reloader will only return in a monitored subprocess
        reloader = hupper.start_reloader('myapp.scripts.serve.main')

        # monitor an extra file
        reloader.watch_files(['foo.ini'])

    waitress.serve(wsgi_app)

Acknowledgments

hupper is inspired by initial work done by Carl J Meyer and David Glick during a Pycon sprint and is built to be a more robust and generic version of Ian Bicking’s excellent PasteScript paste serve --reload and Pyramid’s pserve --reload.

1.0 (2017-05-18)

• Copy sys.path to the worker process and ensure hupper is on the PYTHONPATH so that the subprocess can import it to start the worker. This fixes an issue with how zc.buildout injects dependencies into a process which is done entirely by sys.path manipulation. See https://github.com/Pylons/hupper/pull/27

0.5 (2017-05-10)

• On non-windows systems ensure an exec occurs so that the worker does not share the same process space as the reloader causing certain code that is imported in both to not ever be reloaded. Under the hood this was a significant rewrite to use subprocess instead of multiprocessing. See https://github.com/Pylons/hupper/pull/23

0.4.4 (2017-03-10)

• Fix some versions of Windows which were failing to duplicate stdin to the subprocess and crashing. https://github.com/Pylons/hupper/pull/16

0.4.3 (2017-03-07)

• Fix pdb and other readline-based programs to operate properly. See https://github.com/Pylons/hupper/pull/15

0.4.2 (2017-01-24)

• Pause briefly after receiving a SIGINT to allow the worker to kill itself. If it does not die then it is terminated. See https://github.com/Pylons/hupper/issues/11

• Python 3.6 compatibility.

0.4.1 (2017-01-03)

• Handle errors that may occur when using watchdog to observe non-existent folders.

0.4.0 (2017-01-02)

• Support running any Python module via hupper -m <module>. This is equivalent to python -m except will fully reload the process when files change. See https://github.com/Pylons/hupper/pull/8

0.3.6 (2016-12-18)

• Read the traceback for unknown files prior to crashing. If an import crashes due to a module-scope exception the file that caused the crash would not be tracked but this should help.

0.3.5 (2016-12-17)

• Attempt to send imported paths to the monitor process before crashing to avoid cases where the master is waiting for changes in files that it never started monitoring.

0.3.4 (2016-11-21)

• Add support for globbing using the stdlib glob module. On Python 3.5+ this allows recursive globs using **. Prior to this, the globbing is more limited.

0.3.3 (2016-11-19)

• Fixed a runtime failure on Windows 32-bit systems.

0.3.2 (2016-11-15)

• Support triggering reloads via SIGHUP when hupper detected a crash and is waiting for a file to change.

• Setup the reloader proxy prior to importing the worker’s module. This should allow some work to be done at module-scope instead of in the callable.

0.3.1 (2016-11-06)

• Fix package long description on PyPI.

• Ensure that the stdin file handle is inheritable incase the “spawn” variant of multiprocessing is enabled.

0.3 (2016-11-06)

• Disable bytecode compiling of files imported by the worker process. This should not be necessary when developing and it was causing the process to restart twice on Windows due to how it handles pyc timestamps.

• Fix hupper’s support for forwarding stdin to the worker processes on Python < 3.5 on Windows.

• Fix some possible file descriptor leakage.

• Simplify the hupper.interfaces.IFileMonitor interface by internalizing some of the hupper-specific integrations. They can now focus on just looking for changes.

• Add the hupper.interfaces.IFileMonitorFactory interface to improve the documentation for the callback argument required by hupper.interfaces.IFileMonitor.

0.2 (2016-10-26)

• Windows support!

• Added support for watchdog if it’s installed to do inotify-style file monitoring. This is an optional dependency and hupper will fallback to using polling if it’s not available.

0.1 (2016-10-21)

• Initial release.