added Dockerfile

Dockerfile

@@ -0,0 +1,9 @@
+FROM python:3.7
+WORKDIR /app
+COPY receiver.py .
+COPY requirements.txt .
+RUN python -m pip install -r requirements.txt
+CMD ["python", "/app/receiver.py"]
+
+
+

README.md

@@ -0,0 +1,16 @@
+# Mail Receiver for Healthcheck
+
+This is a simple docker container which acts as SMTP backend and forwards pings from mail to healthchecks.
+
+I made this up, because the docker container I use for healthchecks does not include smtp, and I did not want do maintain this container on my own.
+
+## Usage:
+
+Basically run the docker container with the following environment variables set:
+
+- `PING_URL`: The base url for the ping to healthchecks in the format `https://yourinstance.com/ping/` please do not remove the trailing slash.
+- `PING_ID`: The ID to track the health of this script/container itself.
+- `PING_TIMEOUT`: The time between pings for the script should be done.
+- `MAIL_DOMAIN`: The domain name to accept messages for.
+
+

receiver.py

@@ -3,12 +3,19 @@ import re
 import requests
 from aiosmtpd.controller import Controller
 import os
+import logging
+
+logging.basicConfig(level=logging.INFO)
+
+_logger = logging.getLogger(__name__)
 
 class CustomHandler:
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.domain = os.getenv('MAIL_DOMAIN', 'localhost')
         self.ping_url = os.getenv('PING_URL', 'https://healthcheck.io/ping/')
+        _logger.debug('Mail domain: %s', self.domain)
+        _logger.debug('Mail ping url: %s', self.ping_url)
 
     async def handle_DATA(self, server, session, envelope):
         peer = session.peer
@@ -16,23 +23,28 @@ class CustomHandler:
         rcpt_tos = envelope.rcpt_tos
         data = envelope.content         # type: bytes
         for rcpt in rcpt_tos:
-            print(rcpt)
+            _logger.debug('Cecking to address: %s', rcpt)
             match = re.match(f'([a-zA-Z-_0-9]+)@{self.domain}', rcpt)
             if match is not None:
+                _logger.debug('match found: %s', rcpt)
                 found = match
                 break
         else:
+            _logger.debug('no match found')
             return '500 Could not process your message'
         headers= { 'User-Agent': 'EmailPing from ' + mail_from }
-        requests.get(f'{self.ping_url}{match.group(1)}', headers=headers)
+        url = f'{self.ping_url}{match.group(1)}'
+        _logger.info('Calling Ping url: %s for address: %s', url, mail_from)
+        requests.get(url, headers=headers)
         return '250 OK'
 
 async def health_check():
     ping_url = os.getenv('PING_URL', 'https://healthcheck.io/ping/')
     ping_id = os.getenv('PING_ID', '101fcaa8-32c5-4281-936f-330412b7afa4')
     ping_timeout = os.getenv('PING_TIMEOUT', '60')
+    _logger.info('Reporting own health to: %s', f'{ping_url}{ping_id}')
     while True:
-        requests.get(f'{self.ping_url}{ping_id}')
+        requests.get(f'{ping_url}{ping_id}')
         await asyncio.sleep(ping_timeout)
 
 if __name__ == '__main__':