1. Add new property function in the ApplicationMixin to indicate if Postgres is connected
2. Add a new guard in the RequestHandlerMixin to check that Postgres is connected prior to executing a query, raising a 503 if it is not
3. Catch OperationalError in RequestHandlerMixin and return 503 for it
4. Timeout when waiting on the connection when attempting to reconnect
5. Log when we're creating a new pool
6. Add debug logging to trace when connectios open
7. Add tests that ensure reconnect logic works as expected
- Attempt to add graceful reconfiguration for SRV based connections. On connection failure, the pool will be closed and reopened after fetching to get new SRV records.
- When using SRV, use all return hosts in the PostgreSQL URL
- If multiple requests hit a disconnect error, the reconnect logic will allow the first one in to reconnect and the others to wait
After use in a couple APIs, I found having to check against QueryResult.row and QueryResult.rows too difficult, so this change will always have content in QueryResult.rows, even if it's one row.
In addition, it turns the object into an iterator and adds __repr__ and __len__ magic methods to make interacting with it easier
Even though ``0`` is documented as the max pool size in the aiopg docs, setting it to 0 causes an exception in `aiopg.pool.Pool._fill_free_pool`:
```
File "/Users/gavinr/Source/PSE/anabroker/env/lib/python3.7/site-packages/aiopg/pool.py", line 208, in _fill_free_pool
if override_min and self.size < self.maxsize:
TypeError: '<' not supported between instances of 'int' and 'NoneType'
```
Set to the same default as aiopg, @ 10.
