When connection to Zino server is temporarily lost, Howitz stops working until restarted

[lunkwill42]

If Howitz' connection to a Zino backend is lost (e.g. because of a Zino server restart or some temporary network issue), Howitz becomes useless for all users until the flask web app is restarted.

When the connection is lost and Howitz tries to run an API operation against the lost connection, a very unhelpful error message is shown in the bottom right corner of the page:

This is logged to the console:

INFO howitz in load_user: User "mvold" logged in
127.0.0.1 - - [24/May/2024 11:22:21] "GET /poll_events HTTP/1.1" 500 -
DEBUG zinolib.ritz in _request: send: b'caseids'
ERROR howitz in handle_generic_exception: Exception in /poll_events: [Errno 32] Broken pipe:
Traceback (most recent call last):
  File "/home/mvold/d/howitz/.ve/lib/python3.11/site-packages/flask/app.py", line 1484, in full_dispatch_request
    rv = self.dispatch_request()
         ^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/mvold/d/howitz/.ve/lib/python3.11/site-packages/flask/app.py", line 1469, in dispatch_request
    return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/mvold/d/howitz/src/howitz/endpoints.py", line 343, in poll_events
    poll_events_list = poll_current_events()
                       ^^^^^^^^^^^^^^^^^^^^^
  File "/home/mvold/d/howitz/src/howitz/endpoints.py", line 118, in poll_current_events
    current_app.event_manager.get_events()
  File "/home/mvold/d/howitz/.ve/lib/python3.11/site-packages/zinolib/controllers/zino1.py", line 479, in get_events
    for event_id in self._event_adapter.get_event_ids(self.session.request):
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/mvold/d/howitz/.ve/lib/python3.11/site-packages/zinolib/controllers/zino1.py", line 301, in get_event_ids
    return request.get_caseids()
           ^^^^^^^^^^^^^^^^^^^^^
  File "/home/mvold/d/howitz/.ve/lib/python3.11/site-packages/zinolib/ritz.py", line 547, in get_caseids
    response = self._request(b"caseids")
               ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/mvold/d/howitz/.ve/lib/python3.11/site-packages/zinolib/ritz.py", line 374, in _request
    self._sock.send(command)
BrokenPipeError: [Errno 32] Broken pipe

[hmpf]

There's an improved error message from zinolib 1.0.3 on.

[lunkwill42]

There's an improved error message from zinolib 1.0.3 on.

Yes, but it seems Howitz was inadvertently locked to an older version of zinolib until recently. The error remains, but the message is slightly more helpful now, at least:

Lost connection to server: [Errno 32] Broken pipe