added code to initialise service

code/initialise_app.py

@@ -0,0 +1,55 @@
+from discord_logging.handler import DiscordHandler
+from dotenv import load_dotenv
+import logging
+import os
+
+
+def initialise_app():
+    """
+    Convienience function that ensures eveything is ready before running main loop.
+    """
+    # load environment variables from file
+    load_dotenv()
+    # setup logging
+    fmt = '|%(asctime)s| %(levelname)s %(filename)s:%(funcName)s:%(message)s'
+    datefmt = '%Y-%m-%d %H:%M:%S'
+    logger_level = os.getenv('LOGGER_LEVEL', default=None)
+    if logger_level is None:
+        logger_level = 'info'
+        logging.info(f'environment variable LOGGER_LEVEL not set. Using default (info)')
+    level = getattr(logging, logger_level.upper())
+    logging.basicConfig(format=fmt, datefmt=datefmt, level=level)
+    # setup logging to discord
+    discord_url = os.getenv('DISCORD_URL', default=None)
+    assert discord_url is not None
+    logger = logging.getLogger()
+    discord_handler = DiscordHandler(
+        service_name = 'bandwidth_probing',
+        webhook_url = discord_url,
+    )
+    discord_handler.setFormatter(logging.Formatter('%(message)s'))
+    discord_handler.setLevel(logging.WARNING)
+    logger.addHandler(discord_handler)
+    # ensure environment variables are set
+    necessary_list = [
+        'DB_IP_ADDRESS',
+        'DB_NAME',
+        'DB_COLLECTION_NAME'
+    ]
+    for var in necessary_list:
+        assert var in os.environ, f'environment variable {var} not set.'
+    # set defaults if not yet handled
+    default_dict = {
+        'USER_ID': 0,
+        'REPLICATES': 3,
+        'TRIGGER_INTERVAL_SECONDS': 60
+    }
+    for k, v in default_dict.items():
+        if not k in os.environ:
+            logging.info(f'environment variable {k} not set. Using default ({v}).')
+            os.environ[k] = str(v)
+
+
+if __name__ == '__main__':
+    initialise_app()
+    logging.warning('test message')