functions-framework --debug exits if you save with a syntax error #213
Description
Steps to reproduce:
- Start things up normally
functions-framework \
--source=cloud_function/main.py \
--target=hello_get \
--host=localhost \
--port=18000 \
--debug
This starts up as expected:
``` * Serving Flask app 'hello_get' (lazy loading) * Environment: production WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead. * Debug mode: on WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead. * Running on http://localhost:18000 Press CTRL+C to quit * Restarting with watchdog (fsevents) * Debugger is active! * Debugger PIN: 104-682-644 ```Make a change that introduces a syntax error, and you get:
* Detected change in '/Users/david/src/opvia/app/scripts_v3/cloud_function/main.py', reloading
* Restarting with watchdog (fsevents)
Traceback (most recent call last):
File "/Users/david/src/opvia/app/.venv/bin/functions-framework", line 8, in <module>
sys.exit(_cli())
File "/Users/david/src/opvia/app/.venv/lib/python3.10/site-packages/click/core.py", line 1130, in __call__
return self.main(*args, **kwargs)
File "/Users/david/src/opvia/app/.venv/lib/python3.10/site-packages/click/core.py", line 1055, in main
rv = self.invoke(ctx)
File "/Users/david/src/opvia/app/.venv/lib/python3.10/site-packages/click/core.py", line 1404, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/Users/david/src/opvia/app/.venv/lib/python3.10/site-packages/click/core.py", line 760, in invoke
return __callback(*args, **kwargs)
File "/Users/david/src/opvia/app/.venv/lib/python3.10/site-packages/functions_framework/_cli.py", line 37, in _cli
app = create_app(target, source, signature_type)
File "/Users/david/src/opvia/app/.venv/lib/python3.10/site-packages/functions_framework/__init__.py", line 289, in create_app
spec.loader.exec_module(source_module)
File "<frozen importlib._bootstrap_external>", line 879, in exec_module
File "<frozen importlib._bootstrap_external>", line 1017, in get_code
File "<frozen importlib._bootstrap_external>", line 947, in source_to_code
File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
File "/Users/david/src/opvia/app/scripts_v3/cloud_function/main.py", line 11
///
^^
SyntaxError: invalid syntax
and the process exits
Potential solution:
Apparently this used to be an issue in Flask, but isn't anymore (see https://stackoverflow.com/a/68445450 ). I did some digging to work out how they fixed it, and I think I have a solution:
I think that functions-framework basically needs to do something like this:
in functions_framework/init.py", line 289, in create_app where it does:
with _app.app_context():
spec.loader.exec_module(source_module)- catch the error
- check werkzeug.serving.is_running_from_reloader().
- if true, print the error and create a dummy app that explodes when called
- else re-raise the error