Clean up facade error on bundle download

The following removes an indention when checking for a facade. This
makes it a lot easier to read.

Additionally cleaned up the deploy_bundle example.

Author: SimonRichardson

examples/deploy_bundle.py

@@ -15,33 +15,43 @@ async def main():
     # connect to current controller with current user, per Juju CLI
     await controller.connect()
 
-    bundles = [('cs:~juju-qa/bundle/basic-0', 'beta'), ('juju-qa-bundle-test', None)]
-    for i in range(len(bundles)):
-        deployment = bundles[i]
-        model = await controller.add_model('model{}'.format(i))
-
-        try:
-            print('Deploying bundle')
-            applications = await model.deploy(
-                deployment[0],
-                channel=deployment[1],
-            )
-
-            print('Waiting for active')
-            await model.block_until(
-                lambda: all(unit.workload_status == 'active'
-                            for application in applications for unit in application.units))
-            print("Successfully deployed!")
-            print('Removing bundle')
-            for application in applications:
-                await application.remove()
-        finally:
-            print('Disconnecting from model')
-            await model.disconnect()
-            print("Success")
+    # Deploy charmhub bundle
+    await deploy_bundle(controller, 'juju-qa-bundle-test')
+
+    # Deploy legacy bundle
+    await deploy_bundle(controller, 'cs:~juju-qa/bundle/basic-0', 'beta')
 
     await controller.disconnect()
 
 
+async def deploy_bundle(controller, url, channel=None):
+    models = await controller.list_models()
+    model = await controller.add_model('model{}'.format(len(models) + 1))
+
+    try:
+        print('Deploying bundle')
+
+        applications = await deploy_and_wait_for_bundle(model, url, channel)
+
+        print("Successfully deployed!")
+        print('Removing bundle')
+        for application in applications:
+            await application.remove()
+    finally:
+        print('Disconnecting from model')
+        await model.disconnect()
+        print("Success")
+
+
+async def deploy_and_wait_for_bundle(model, url, channel=None):
+    applications = await model.deploy(url, channel=channel)
+
+    print('Waiting for active')
+    await model.block_until(
+        lambda: all(unit.workload_status == 'active'
+                    for application in applications for unit in application.units))
+
+    return applications
+
 if __name__ == '__main__':
     loop.run(main())

juju/bundle.py

@@ -178,36 +178,36 @@ async def fetch_plan(self, charm_url, origin):
             raise JujuError(self.plan.errors)
 
     async def _download_bundle(self, charm_url, origin):
-        if self.charms_facade is not None:
-            resp = await self.charms_facade.GetDownloadInfos(entities=[{
-                'charm-url': str(charm_url),
-                'charm-origin': {
-                    'source': origin.source,
-                    'type': origin.type_,
-                    'id': origin.id_,
-                    'hash': origin.hash_,
-                    'revision': origin.revision,
-                    'risk': origin.risk,
-                    'track': origin.track,
-                    'architecture': origin.architecture,
-                    'os': origin.os,
-                    'series': origin.series,
-                }
-            }])
-            if len(resp.results) != 1:
-                raise JujuError("expected one result, received {}".format(resp.results))
-
-            result = resp.results[0]
-            if not result.url:
-                raise JujuError("no url found for bundle {}".format(charm_url.name))
-
-            bundle_resp = requests.get(result.url)
-            bundle_resp.raise_for_status()
-
-            with closing(bundle_resp), zipfile.ZipFile(io.BytesIO(bundle_resp.content)) as archive:
-                return self._get_bundle_yaml(archive)
-
-        raise JujuError('charm facade not supported')
+        if self.charms_facade is None:
+            raise JujuError('unable to download bundle for {} using the new charms facade. Upgrade controller to proceed.'.format(charm_url))
+
+        resp = await self.charms_facade.GetDownloadInfos(entities=[{
+            'charm-url': str(charm_url),
+            'charm-origin': {
+                'source': origin.source,
+                'type': origin.type_,
+                'id': origin.id_,
+                'hash': origin.hash_,
+                'revision': origin.revision,
+                'risk': origin.risk,
+                'track': origin.track,
+                'architecture': origin.architecture,
+                'os': origin.os,
+                'series': origin.series,
+            }
+        }])
+        if len(resp.results) != 1:
+            raise JujuError("expected one result, received {}".format(resp.results))
+
+        result = resp.results[0]
+        if not result.url:
+            raise JujuError("no url found for bundle {}".format(charm_url.name))
+
+        bundle_resp = requests.get(result.url)
+        bundle_resp.raise_for_status()
+
+        with closing(bundle_resp), zipfile.ZipFile(io.BytesIO(bundle_resp.content)) as archive:
+            return self._get_bundle_yaml(archive)
 
     def _get_bundle_yaml(self, archive):
         for member in archive.infolist():