App can't rebuild database components on its own

Beginne in proxstar/db.py bei get_pool_cache und dem Pool_Cache-Modell und verfolge dann proxstar/init.py, wo list_vms es aufruft. Ermittle, wie Datenbankschemas derzeit erstellt oder verwaltet werden; als abgeschlossen gilt, dass eine fehlende pool_cache-Tabelle und idealerweise auch andere fehlende Schemas ohne manuelle Datenbankintervention wiederhergestellt werden können und die VM-Auflistung wieder funktioniert.

I deleted the pool_cache table because Proxstar was erroring about it, expecting it to re-build it (since, y'know, it's a cache!), but now it's sad.

/usr/local/lib/python3.8/site-packages/rq_dashboard/legacy_config.py:26: UserWarning: Configuration option REDIS_HOST is depricated and will be removed in future versions. Please use RQ_DASHBOARD_REDIS_HOST instead.
  warnings.warn(warning_template.format(old_name=old_name, new_name=new_name), UserWarning)
/usr/local/lib/python3.8/site-packages/rq_dashboard/legacy_config.py:26: UserWarning: Configuration option REDIS_PORT is depricated and will be removed in future versions. Please use RQ_DASHBOARD_REDIS_PORT instead.
  warnings.warn(warning_template.format(old_name=old_name, new_name=new_name), UserWarning)
2022-08-04 21:39:08,890 ERROR Exception on / [GET]
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/sqlalchemy/engine/base.py", line 1276, in _execute_context
    self.dialect.do_execute(
  File "/usr/local/lib/python3.8/site-packages/sqlalchemy/engine/default.py", line 609, in do_execute
    cursor.execute(statement, parameters)
  File "/usr/local/lib/python3.8/site-packages/ddtrace/contrib/dbapi/__init__.py", line 118, in execute
    return self._trace_method(self.__wrapped__.execute, self._self_datadog_name, query, {}, query, *args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/ddtrace/contrib/psycopg/patch.py", line 69, in _trace_method
    return super(Psycopg2TracedCursor, self)._trace_method(method, name, resource, extra_tags, *args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/ddtrace/contrib/dbapi/__init__.py", line 81, in _trace_method
    return method(*args, **kwargs)
psycopg2.errors.UndefinedTable: relation "pool_cache" does not exist
LINE 2: FROM pool_cache
             ^


The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/flask/app.py", line 2447, in wsgi_app
    response = self.full_dispatch_request()
  File "/usr/local/lib/python3.8/site-packages/flask/app.py", line 1952, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/usr/local/lib/python3.8/site-packages/ddtrace/contrib/flask/helpers.py", line 25, in wrapper
    return func(pin, wrapped, instance, args, kwargs)
  File "/usr/local/lib/python3.8/site-packages/ddtrace/contrib/flask/helpers.py", line 36, in wrapper
    return wrapped(*args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/flask/app.py", line 1821, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/local/lib/python3.8/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/usr/local/lib/python3.8/site-packages/flask/app.py", line 1950, in full_dispatch_request
    rv = self.dispatch_request()
  File "/usr/local/lib/python3.8/site-packages/ddtrace/contrib/flask/helpers.py", line 25, in wrapper
    return func(pin, wrapped, instance, args, kwargs)
  File "/usr/local/lib/python3.8/site-packages/ddtrace/contrib/flask/patch.py", line 481, in _traced_request
    return wrapped(*args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/flask/app.py", line 1936, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/usr/local/lib/python3.8/site-packages/ddtrace/contrib/flask/wrappers.py", line 25, in trace_func
    return wrapped(*args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/flask_pyoidc/flask_pyoidc.py", line 253, in wrapper
    return view_func(*args, **kwargs)
  File "/opt/proxstar/proxstar/__init__.py", line 197, in list_vms
    vms = get_pool_cache(db)
  File "/opt/proxstar/proxstar/db.py", line 113, in get_pool_cache
    db_pools = db.query(Pool_Cache).all()
  File "/usr/local/lib/python3.8/site-packages/sqlalchemy/orm/query.py", line 3373, in all
    return list(self)
  File "/usr/local/lib/python3.8/site-packages/sqlalchemy/orm/query.py", line 3535, in __iter__
    return self._execute_and_instances(context)
  File "/usr/local/lib/python3.8/site-packages/sqlalchemy/orm/query.py", line 3560, in _execute_and_instances
    result = conn.execute(querycontext.statement, self._params)
  File "/usr/local/lib/python3.8/site-packages/sqlalchemy/engine/base.py", line 1011, in execute
    return meth(self, multiparams, params)
  File "/usr/local/lib/python3.8/site-packages/sqlalchemy/sql/elements.py", line 298, in _execute_on_connection
    return connection._execute_clauseelement(self, multiparams, params)
  File "/usr/local/lib/python3.8/site-packages/sqlalchemy/engine/base.py", line 1124, in _execute_clauseelement
    ret = self._execute_context(
  File "/usr/local/lib/python3.8/site-packages/sqlalchemy/engine/base.py", line 1316, in _execute_context
    self._handle_dbapi_exception(
  File "/usr/local/lib/python3.8/site-packages/sqlalchemy/engine/base.py", line 1510, in _handle_dbapi_exception
    util.raise_(
  File "/usr/local/lib/python3.8/site-packages/sqlalchemy/util/compat.py", line 182, in raise_
    raise exception
  File "/usr/local/lib/python3.8/site-packages/sqlalchemy/engine/base.py", line 1276, in _execute_context
    self.dialect.do_execute(
  File "/usr/local/lib/python3.8/site-packages/sqlalchemy/engine/default.py", line 609, in do_execute
    cursor.execute(statement, parameters)
  File "/usr/local/lib/python3.8/site-packages/ddtrace/contrib/dbapi/__init__.py", line 118, in execute
    return self._trace_method(self.__wrapped__.execute, self._self_datadog_name, query, {}, query, *args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/ddtrace/contrib/psycopg/patch.py", line 69, in _trace_method
    return super(Psycopg2TracedCursor, self)._trace_method(method, name, resource, extra_tags, *args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/ddtrace/contrib/dbapi/__init__.py", line 81, in _trace_method
    return method(*args, **kwargs)
sqlalchemy.exc.ProgrammingError: (psycopg2.errors.UndefinedTable) relation "pool_cache" does not exist
LINE 2: FROM pool_cache
             ^

[SQL: SELECT pool_cache.pool AS pool_cache_pool, pool_cache.vms AS pool_cache_vms, pool_cache.num_vms AS pool_cache_num_vms, pool_cache.usage AS pool_cache_usage, pool_cache.limits AS pool_cache_limits, pool_cache.percents AS pool_cache_percents 
FROM pool_cache]
(Background on this error at: http://sqlalche.me/e/13/f405)

It'd be cool if the app could re-build its missing schemas on its own or something.