Check connections before launching

* qc_app/__init__.py (refactor): Check connection before launching the
  application
* qc_app/check_connections.py (new file): Add code to check
  connections
* qc_app/db_utils.py (refactor): enable passing the database uri as an
  argument to the connection creation function.
* scripts/worker.py (refactor): Use new code to check for redis
  connection.

1 files changed, 2 insertions, 5 deletions

diff --git a/scripts/worker.py b/scripts/worker.py
index 4077ad1..fee4ec8 100644
--- a/scripts/worker.py
+++ b/scripts/worker.py
@@ -10,6 +10,7 @@ from tempfile import TemporaryFile
 from redis import Redis
 
 from qc_app import jobs
+from qc_app.check_connections import check_redis
 
 def parse_args():
     "Parse the command-line arguments"
@@ -21,11 +22,7 @@ def parse_args():
     parser.add_argument("job_id", help="The id of the job being processed")
 
     args = parser.parse_args()
-    try:
-        conn = Redis.from_url(args.redisurl) # pylint: disable=[unused-variable]
-    except ConnectionError as conn_err: # pylint: disable=[unused-variable]
-        print(traceback.format_exc(), file=sys.stderr)
-        sys.exit(1)
+    check_redis(args.redisurl)
 
     return args