Fix TypeError when you try to replace default port

[marctc]

An exception occurs if you set an env var for the exporter port (PGBOUNCER_EXPORTER_PORT=9100).

Traceback (most recent call last):
  File "/usr/local/lib/python3.6/threading.py", line 916, in _bootstrap_inner
    self.run()
  File "/usr/local/lib/python3.6/site-packages/prometheus_client/exposition.py", line 105, in run
    httpd = ThreadingSimpleServer((addr, port), MetricsHandler)
  File "/usr/local/lib/python3.6/socketserver.py", line 453, in __init__
    self.server_bind()
  File "/usr/local/lib/python3.6/http/server.py", line 136, in server_bind
    socketserver.TCPServer.server_bind(self)
  File "/usr/local/lib/python3.6/socketserver.py", line 467, in server_bind
    self.socket.bind(self.server_address)
TypeError: an integer is required (got type str)

The replacer parses the yaml giving the following dict:

{'exporter_host': '127.0.0.1', 'exporter_port': '9128', 'pgbouncers': [{'dsn': 'postgresql://user:pass@127.0.0.1:6543/pgbouncer', 'connect_timeout': 5}]}

So casting the port to an int in getExporterPort function think that could be enough for fixing the issue.

[pracucci]

Thanks @marctc for patching it and sorry for my late review. I've published a new version (1.0.1) including your fix: https://pypi.org/project/prometheus-pgbouncer-exporter/#history

[marctc]

Thanks to you!!