Fix sent_at KeyError (#440)

* Improve logging

* Ensure sent_at is set in echo email

opwen_email_server/actions.py

@@ -39,7 +39,7 @@ def __call__(self, *args, **kwargs) -> Response:
         try:
             return self._action(*args, **kwargs)
         except Exception as ex:
-            self.log_exception(ex, 'error in action %s', self.__class__.__name__)
+            self.log_exception(ex, '%s(args=%r, kwargs=%r)', self.__class__.__name__, args, kwargs)
             raise ex
 
     def _action(self, *args, **kwargs) -> Response:

opwen_email_server/mailers/echo.py

@@ -1,10 +1,17 @@
+from datetime import datetime
+from typing import Callable
+
 from opwen_email_server.utils.log import LogMixin
 
 ECHO_ADDRESS = 'echo@bot.lokole.ca'
 
 
 class EchoEmailFormatter(LogMixin):
+    def __init__(self, now: Callable[[], datetime] = datetime.utcnow):
+        self._now = now
+
     def __call__(self, email: dict) -> dict:
         email['to'] = [email['from']]
         email['from'] = ECHO_ADDRESS
+        email['sent_at'] = self._now().strftime('%Y-%m-%d %H:%M')
         return email