Startup fails if nodes.json cannot be fetched

[1977er]

barfs traceback and dies.

Dez 30 23:06:14 harvester systemd[1]: Started The KeepItUp Worker pings and sends notification mails.
Dez 30 23:06:16 harvester python[585]: ping_worker.py, 451 nodes loaded.
Dez 30 23:06:16 harvester python[585]: Traceback (most recent call last):
Dez 30 23:06:16 harvester python[585]:   File "/opt/keepitup/venv/lib/python3.7/site-packages/urllib3/connection.py", line 170, in _new_conn
Dez 30 23:06:16 harvester python[585]:     (self._dns_host, self.port), self.timeout, **extra_kw
Dez 30 23:06:16 harvester python[585]:   File "/opt/keepitup/venv/lib/python3.7/site-packages/urllib3/util/connection.py", line 96, in create_connection
Dez 30 23:06:16 harvester python[585]:     raise err
Dez 30 23:06:16 harvester python[585]:   File "/opt/keepitup/venv/lib/python3.7/site-packages/urllib3/util/connection.py", line 86, in create_connection
Dez 30 23:06:16 harvester python[585]:     sock.connect(sa)
Dez 30 23:06:16 harvester python[585]: ConnectionRefusedError: [Errno 111] Connection refused
Dez 30 23:06:16 harvester python[585]: During handling of the above exception, another exception occurred:
Dez 30 23:06:16 harvester python[585]: Traceback (most recent call last):
Dez 30 23:06:16 harvester python[585]:   File "/opt/keepitup/venv/lib/python3.7/site-packages/urllib3/connectionpool.py", line 706, in urlopen
Dez 30 23:06:16 harvester python[585]:     chunked=chunked,
Dez 30 23:06:16 harvester python[585]:   File "/opt/keepitup/venv/lib/python3.7/site-packages/urllib3/connectionpool.py", line 382, in _make_request
Dez 30 23:06:16 harvester python[585]:     self._validate_conn(conn)
Dez 30 23:06:16 harvester python[585]:   File "/opt/keepitup/venv/lib/python3.7/site-packages/urllib3/connectionpool.py", line 1010, in _validate_conn
Dez 30 23:06:16 harvester python[585]:     conn.connect()
Dez 30 23:06:16 harvester python[585]:   File "/opt/keepitup/venv/lib/python3.7/site-packages/urllib3/connection.py", line 353, in connect
Dez 30 23:06:16 harvester python[585]:     conn = self._new_conn()
Dez 30 23:06:16 harvester python[585]:   File "/opt/keepitup/venv/lib/python3.7/site-packages/urllib3/connection.py", line 182, in _new_conn
Dez 30 23:06:16 harvester python[585]:     self, "Failed to establish a new connection: %s" % e
Dez 30 23:06:16 harvester python[585]: urllib3.exceptions.NewConnectionError: <urllib3.connection.HTTPSConnection object at 0x7f73b3c938d0>: Failed to establish a new connection:
Dez 30 23:06:16 harvester python[585]: During handling of the above exception, another exception occurred:
Dez 30 23:06:16 harvester python[585]: Traceback (most recent call last):
Dez 30 23:06:16 harvester python[585]:   File "/opt/keepitup/venv/lib/python3.7/site-packages/requests/adapters.py", line 449, in send
Dez 30 23:06:16 harvester python[585]:     timeout=timeout
Dez 30 23:06:16 harvester python[585]:   File "/opt/keepitup/venv/lib/python3.7/site-packages/urllib3/connectionpool.py", line 756, in urlopen
Dez 30 23:06:16 harvester python[585]:     method, url, error=e, _pool=self, _stacktrace=sys.exc_info()[2]
Dez 30 23:06:16 harvester python[585]:   File "/opt/keepitup/venv/lib/python3.7/site-packages/urllib3/util/retry.py", line 573, in increment
Dez 30 23:06:16 harvester python[585]:     raise MaxRetryError(_pool, url, error or ResponseError(cause))
Dez 30 23:06:16 harvester python[585]: urllib3.exceptions.MaxRetryError: HTTPSConnectionPool(host='harvester.ffh.zone', port=443): Max retries exceeded with url: /api/nodes.json
Dez 30 23:06:16 harvester python[585]: During handling of the above exception, another exception occurred:
Dez 30 23:06:16 harvester python[585]: Traceback (most recent call last):
Dez 30 23:06:16 harvester python[585]:   File "/opt/keepitup/ping_worker.py", line 19, in <module>
Dez 30 23:06:16 harvester python[585]:     nodes_json_cache.update()
Dez 30 23:06:16 harvester python[585]:   File "/opt/keepitup/main.py", line 144, in update
Dez 30 23:06:16 harvester python[585]:     res = requests.get(NODES_JSON_URL)
Dez 30 23:06:16 harvester python[585]:   File "/opt/keepitup/venv/lib/python3.7/site-packages/requests/api.py", line 76, in get
Dez 30 23:06:16 harvester python[585]:     return request('get', url, params=params, **kwargs)
Dez 30 23:06:16 harvester python[585]:   File "/opt/keepitup/venv/lib/python3.7/site-packages/requests/api.py", line 61, in request
Dez 30 23:06:16 harvester python[585]:     return session.request(method=method, url=url, **kwargs)
Dez 30 23:06:16 harvester python[585]:   File "/opt/keepitup/venv/lib/python3.7/site-packages/requests/sessions.py", line 542, in request
Dez 30 23:06:16 harvester python[585]:     resp = self.send(prep, **send_kwargs)
Dez 30 23:06:16 harvester python[585]:   File "/opt/keepitup/venv/lib/python3.7/site-packages/requests/sessions.py", line 655, in send
Dez 30 23:06:16 harvester python[585]:     r = adapter.send(request, **kwargs)
Dez 30 23:06:16 harvester python[585]:   File "/opt/keepitup/venv/lib/python3.7/site-packages/requests/adapters.py", line 516, in send
Dez 30 23:06:16 harvester python[585]:     raise ConnectionError(e, request=request)
Dez 30 23:06:16 harvester python[585]: requests.exceptions.ConnectionError: HTTPSConnectionPool(host='harvester.ffh.zone', port=443): Max retries exceeded with url: /api/nodes.js