Allow configuring how many hours back to collect with HOURS env var

ec2price/app.py

@@ -27,6 +27,7 @@
     '/(?P<dbname>.+)'
 )
 DATABASE_URL_EXAMPLE = 'postgres://username:password@host:port/dbname'
+_HOURS = 8
 
 
 class ArgumentParser(argparse.ArgumentParser):
@@ -119,6 +120,7 @@ def main(args):
         _start_tornado_app(debug, cookie_secret, port, address, handlers)
     elif opts.cmd == 'collector':
         database_url = os.getenv('DATABASE_URL')
+        hours = os.getenv('HOURS')
 
         database_dsn = None
         if database_url:
@@ -131,9 +133,16 @@ def main(args):
         if not database_url:
             parser.error('DATABASE_URL is required')
 
+        if not hours:
+            hours = _HOURS
+        try:
+            hours = int(hours)
+        except ValueError:
+            parser.error('HOURS must be an integer')
+
         db_conn = _get_db_conn(database_dsn)
 
-        collect(db_conn)
+        collect(db_conn, hours)
     return 0
 
 

ec2price/collector.py

@@ -9,7 +9,6 @@
 import uuid
 
 
-_HOURS = 8
 _FMT = '%Y-%m-%dT%H:%M:%S.000Z'
 
 _SELECT_SPOT_PRICE = """
@@ -39,12 +38,12 @@
 logging.getLogger('requests.packages.urllib3').setLevel(logging.WARN)
 
 
-def collect(db_conn):
+def collect(db_conn, hours):
     session = botocore.session.get_session()
     ec2 = session.get_service('ec2')
     operation = ec2.get_operation('DescribeSpotPriceHistory')
 
-    d = datetime.datetime.utcnow() - datetime.timedelta(hours=_HOURS)
+    d = datetime.datetime.utcnow() - datetime.timedelta(hours=hours)
     start_time = d.strftime(_FMT)
 
     with contextlib.closing(db_conn.cursor()) as cursor: