Updates handling of scale/replicas args in CLI & compose file (Issue: containers#267)

Author: me-coder

podman_compose.py

@@ -2080,7 +2080,17 @@ def _parse_compose_file(self):
         container_names_by_service = {}
         self.services = services
         for service_name, service_desc in services.items():
-            replicas = try_int(service_desc.get("deploy", {}).get("replicas"), fallback=1)
+            replicas = try_int(args.scale, fallback=1) if "scale" in args else 1
+            # Skip `scale` or `replicas` check from compose yaml
+            # if `--scale=<NUM>` is specifiec in CLI arg
+            if 1 == replicas:
+                if "scale" in service_desc:
+                    # Attempt to read parameter scale for service from compose yaml file
+                    replicas = try_int(service_desc.get("scale"), fallback=1)
+                if "replicas" in service_desc:
+                    # Attempt to read parameter deploy.replicas for service from compose yaml file
+                    # Note: both conditions are necessary to handle case if `has_key("deploy")` is false
+                    replicas = try_int(service_desc.get("deploy", {}).get("replicas"), fallback=1)
 
             container_names_by_service[service_name] = []
             for num in range(1, replicas + 1):
@@ -3366,12 +3376,15 @@ def compose_up_parse(parser):
         action="store_true",
         help="Remove containers for services not defined in the Compose file.",
     )
+    # `--scale` argument needs to store as single valye and not append,
+    # as multiple scale values could be confusing.
     parser.add_argument(
         "--scale",
-        metavar="SERVICE=NUM",
-        action="append",
+        # action="store",
         help="Scale SERVICE to NUM instances. Overrides the `scale` setting in the Compose file if "
         "present.",
+        metavar="SERVICE=NUM",
+        type=int,
     )
     parser.add_argument(
         "--exit-code-from",