Gateway: Fixed logging to be consistent and use client IP

* Send all the bottle server output through our logger.
* Ensure gevent uses client IP, not 127.0.0.1.

src/eddn/Gateway.py

@@ -14,6 +14,7 @@ from typing import Dict
 from urllib.parse import parse_qs
 
 import gevent
+import gevent.pywsgi
 import simplejson
 import zmq.green as zmq
 from gevent import monkey
@@ -424,6 +425,55 @@ def apply_cors() -> None:
     )
 
 
+class EDDNWSGIHandler(gevent.pywsgi.WSGIHandler):
+    """iHandles overriding request logging."""
+
+    def format_request(self):
+        """
+        Format information about the request for logging.
+
+        The default causes, e.g.:
+
+        <client IP> - - [2022-03-12 16:44:39] "POST /upload/ HTTP/1.1" 400 399 0.000566
+
+        and makes no attempt to handle reverse proxying where we know that
+        X-Forwarded-For has been set by our reverse proxy.  So this will use
+        that header if present to output the correct IP.
+
+        Also, as we're pointing output at our logger, there is no need to
+        include a timestamp in the output.
+
+        This is why we're overriding *this* and not `handle_one_response()`,
+        where we'd change self.client_address there instead.  This does,
+        unfortunately, mean re-creating most of the super-class'es version
+        of the function.
+
+        Resulting output:
+
+        2022-03-12 16:44:39.132 - INFO - pywsgi:1226: <client IP> - - "POST /upload/ HTTP/1.1" 400 399 0.000566
+        """
+        # Start with the same as the super-class would use...
+        client_address = self.client_address[0] if isinstance(self.client_address, tuple) else self.client_address
+
+        # ... but now over-ride it if the header is set.
+        if self.environ.get("HTTP_X_FORWARDED_FOR"):
+            client_address = self.environ["HTTP_X_FORWARDED_FOR"]
+
+        length = self.response_length or '-'
+
+        if self.time_finish:
+            d = self.time_finish - self.time_start
+            delta = f"{d:6f}"
+
+        else:
+            delta = '-'
+
+        # This differs from the super-class version in not having a datestamp
+        return f"{client_address or '-'} - - \"{self.requestline or '-'}\"" \
+               f" {(self._orig_status or self.status or '000').split()[0]}" \
+               f" {length} {delta}"
+
+
 def main() -> None:
     """Handle setting up and running the bottle app."""
     cl_args = parse_cl_args()
@@ -434,10 +484,13 @@ def main() -> None:
     configure()
 
     app.add_hook("after_request", apply_cors)
+    # app.install(custom_logging)
     app.run(
         host=Settings.GATEWAY_HTTP_BIND_ADDRESS,
         port=Settings.GATEWAY_HTTP_PORT,
         server="gevent",
+        log=gevent.pywsgi.LoggingLogAdapter(logger),
+        handler_class=EDDNWSGIHandler,
     )