Add ability to listen on unix sockets

Introduces a way to tell the app to listen on unix socket instead of
host:port.

Fixes #436

app/routes.py

@@ -512,6 +512,11 @@ def run_app() -> None:
         default='127.0.0.1',
         metavar='<ip address>',
         help='Specifies the host address to use (default 127.0.0.1)')
+    parser.add_argument(
+        '--unix-socket',
+        default='',
+        metavar='</path/to/unix.sock>',
+        help='Listen for app on unix socket instead of host:port')
     parser.add_argument(
         '--debug',
         default=False,
@@ -562,5 +567,7 @@ def run_app() -> None:
 
     if args.debug:
         app.run(host=args.host, port=args.port, debug=args.debug)
+    elif args.unix_socket:
+        waitress.serve(app, unix_socket=args.unix_socket)
     else:
         waitress.serve(app, listen="{}:{}".format(args.host, args.port))

run

@@ -3,7 +3,7 @@
 # ./run # Runs the full web app
 # ./run test # Runs the testing suite
 
-set -eu
+set -e
 
 SCRIPT_DIR="$(CDPATH= command cd -- "$(dirname -- "$0")" && pwd -P)"
 
@@ -24,7 +24,13 @@ if [ "$SUBDIR" = "test" ]; then
     pytest -sv
 else
     mkdir -p "$STATIC_FOLDER"
-    python3 -um app \
-      --host "${ADDRESS:-0.0.0.0}" \
-      --port "${PORT:-"${EXPOSE_PORT:-5000}"}"
+
+    if [ ! -z "$UNIX_SOCKET" ]; then
+        python3 -um app \
+          --unix-socket "$UNIX_SOCKET"
+    else
+        python3 -um app \
+          --host "${ADDRESS:-0.0.0.0}" \
+          --port "${PORT:-"${EXPOSE_PORT:-5000}"}"
+    fi
 fi