Fix bug 1448: minor fix in JujuModelWatcher.wait_for_model
[osm/N2VC.git] / n2vc / juju_watcher.py
index 842e990..04ad10f 100644 (file)
@@ -35,6 +35,13 @@ def status(application: Application) -> str:
 
 
 def entity_ready(entity: ModelEntity) -> bool:
+    """
+    Check if the entity is ready
+
+    :param: entity: Model entity. It can be a machine, action, or application.
+
+    :returns: boolean saying if the entity is ready or not
+    """
     entity_type = entity.entity_type
     if entity_type == "machine":
         return entity.agent_status in ["started"]
@@ -42,15 +49,73 @@ def entity_ready(entity: ModelEntity) -> bool:
         return entity.status in ["completed", "failed", "cancelled"]
     elif entity_type == "application":
         # Workaround for bug: https://github.com/juju/python-libjuju/issues/441
-        return status(entity) in ["active", "blocked"]
+        return entity.status in ["active", "blocked"]
     else:
         raise EntityInvalidException("Unknown entity type: {}".format(entity_type))
 
 
+def application_ready(application: Application) -> bool:
+    """
+    Check if an application has a leader
+
+    :param: application: Application entity.
+
+    :returns: boolean saying if the application has a unit that is a leader.
+    """
+    ready_status_list = ["active", "blocked"]
+    application_ready = application.status in ready_status_list
+    units_ready = all(
+        unit.workload_status in ready_status_list for unit in application.units
+    )
+    return application_ready and units_ready
+
+
 class JujuModelWatcher:
     @staticmethod
+    async def wait_for_model(model: Model, timeout: float = 3600):
+        """
+        Wait for all entities in model to reach its final state.
+
+        :param: model:              Model to observe
+        :param: timeout:            Timeout for the model applications to be active
+
+        :raises: asyncio.TimeoutError when timeout reaches
+        """
+
+        if timeout is None:
+            timeout = 3600.0
+
+        # Coroutine to wait until the entity reaches the final state
+        async def wait_until_model_ready():
+            wait_for_entity = asyncio.ensure_future(
+                asyncio.wait_for(
+                    model.block_until(
+                        lambda: all(
+                            application_ready(application)
+                            for application in model.applications.values()
+                        ),
+                    ),
+                    timeout=timeout,
+                )
+            )
+
+            tasks = [wait_for_entity]
+            try:
+                await asyncio.wait(tasks, return_when=asyncio.FIRST_COMPLETED)
+            finally:
+                # Cancel tasks
+                for task in tasks:
+                    task.cancel()
+
+        await wait_until_model_ready()
+        # Check model is still ready after 10 seconds
+
+        await asyncio.sleep(10)
+        await wait_until_model_ready()
+
+    @staticmethod
     async def wait_for(
-        model,
+        model: Model,
         entity: ModelEntity,
         progress_timeout: float = 3600,
         total_timeout: float = 3600,
@@ -82,7 +147,8 @@ class JujuModelWatcher:
         # Coroutine to wait until the entity reaches the final state
         wait_for_entity = asyncio.ensure_future(
             asyncio.wait_for(
-                model.block_until(lambda: entity_ready(entity)), timeout=total_timeout,
+                model.block_until(lambda: entity_ready(entity)),
+                timeout=total_timeout,
             )
         )
 
@@ -103,8 +169,6 @@ class JujuModelWatcher:
             # Execute tasks, and stop when the first is finished
             # The watcher task won't never finish (unless it timeouts)
             await asyncio.wait(tasks, return_when=asyncio.FIRST_COMPLETED)
-        except Exception as e:
-            raise e
         finally:
             # Cancel tasks
             for task in tasks: