Pass metadata into get_charm_series to avoid multiple file reads at each deploy

Author: cderici

juju/application.py

@@ -823,9 +823,12 @@ async def local_refresh(
 
         series = (
             await self.get_series() or
-            self.model.info.get('default-series', '') or
-            await get_charm_series(charm_dir, self.model)
+            self.model.info.get('default-series', '')
         )
+        if not series:
+            metadata = utils.get_local_charm_metadata(charm_dir)
+            await get_charm_series(metadata, self.model)
+
         if not series:
             default_series = model_config.get("default-series")
             if default_series:

juju/bundle.py

@@ -124,11 +124,10 @@ async def _handle_local_charms(self, bundle, bundle_dir):
                 pass
             except FileNotFoundError:
                 continue
-            series = (
-                app_dict.get('series') or
-                default_series or
-                await get_charm_series(charm_dir, self.model)
-            )
+            series = (app_dict.get('series') or default_series)
+            if not series:
+                metadata = utils.get_local_charm_metadata(charm_dir)
+                series = await get_charm_series(metadata, self.model)
             if not self.model.connection().is_using_old_client and not series:
                 raise JujuError(
                     "Couldn't determine series for charm at {}. "
@@ -430,32 +429,17 @@ def is_local_charm(charm_url):
     return charm_url.startswith('.') or charm_url.startswith('local:') or os.path.isabs(charm_url)
 
 
-async def get_charm_series(path, model):
-    """Inspects the charm directory at ``path`` and returns a default
-    series from its metadata.yaml (the first item in the 'series' list).
+async def get_charm_series(metadata, model):
+    """Inspects the given metadata and returns a default series from its
+    metadata.yaml (the first item in the 'series' list).
 
-    Tries to extract the informiation from the given model if no
-    series is determined from the path.
+    Tries to extract the information from the given model if no
+    series is determined from the given metadata.
     Returns None if no series can be determined.
 
     """
-    path = Path(path)
-    try:
-        if path.suffix == '.charm':
-            md = "metadata.yaml in %s" % path
-            with zipfile.ZipFile(str(path), 'r') as charm_file:
-                data = yaml.safe_load(charm_file.read('metadata.yaml'))
-        else:
-            md = path / "metadata.yaml"
-            if not md.exists():
-                return None
-            data = yaml.safe_load(md.open())
-    except yaml.YAMLError as exc:
-        if hasattr(exc, "problem_mark"):
-            mark = exc.problem_mark
-            log.error("Error parsing YAML file {}, line {}, column: {}".format(md, mark.line, mark.column))
-        raise
-    _series = data.get('series')
+
+    _series = metadata.get('series')
     series = _series[0] if _series else None
 
     if series is None:

juju/model.py

@@ -1795,14 +1795,11 @@ async def deploy(
                                                                 identifier)
             else:
                 # We have a local charm dir that needs to be uploaded
-                charm_dir = os.path.abspath(
-                    os.path.expanduser(identifier))
+                charm_dir = os.path.abspath(os.path.expanduser(identifier))
                 charm_origin = res.origin
 
                 metadata = utils.get_local_charm_metadata(charm_dir)
-                # TODO (cderici) : pass the metadata into get_charm_series, as
-                #  it also reads that file redundantly
-                charm_series = charm_series or await get_charm_series(charm_dir,
+                charm_series = charm_series or await get_charm_series(metadata,
                                                                       self)
 
                 # If we're using a newer client, then the CharmOrigin needs a