Use Lambda event object to set env vars

README.rst

@@ -50,7 +50,7 @@ If you need to deploy a new package outside of Travis then do the following, *no
 Configuration
 ^^^^^^^^^^^^^
 
-In order for the Lambda to run, carbon needs a few environment variables set.
+In order for the Lambda to run, carbon needs a few environment variables set. These can either be set in the environment or passed to the Lambda function through the event JSON object. Variables set using the event object will overwrite those set in the environment.
 
 +-----------+-------------------------------------------------------------+
 | Variable  | Description                                                 |

carbon/app.py

@@ -44,6 +44,9 @@
     'VISITING SENIOR LECTURER', 'PART-TIME FLEXIBLE/LL',
 )
 
+ENV_VARS = ('FTP_USER', 'FTP_PASS', 'FTP_PATH', 'FTP_HOST', 'FTP_PORT',
+            'CARBON_DB')
+
 
 def people():
     """A person generator.
@@ -301,8 +304,7 @@ class Config(dict):
     @classmethod
     def from_env(cls):
         cfg = cls()
-        for var in ['FTP_USER', 'FTP_PASS', 'FTP_PATH', 'FTP_HOST',
-                    'CARBON_DB', ]:
+        for var in ENV_VARS:
             cfg[var] = os.environ.get(var)
         return cfg
 

lambda.py

@@ -3,7 +3,7 @@
 
 import boto3
 
-from carbon.app import Config, FTPFeeder
+from carbon.app import Config, ENV_VARS, FTPFeeder
 from carbon.db import engine
 
 
@@ -12,6 +12,7 @@ def handler(event, context):
     secret = client.get_secret_value(SecretId=os.environ['SECRET_ID'])
     secret_env = json.loads(secret['SecretString'])
     cfg = Config.from_env()
+    cfg.update({k: event[k] for k in ENV_VARS if k in event})
     cfg.update(secret_env)
     engine.configure(cfg['CARBON_DB'])
     FTPFeeder(event, context, cfg).run()