Introducing Machine for OpenStackApplication (#298)

In data-plane upgrade, we will need to have Machine object, which will
be used during hypervisor upgrade.

---------

Co-authored-by: Gabriel Cocenza <[email protected]>
Co-authored-by: TQ X <[email protected]>

cou/apps/base.py

@@ -38,7 +38,7 @@
     UpgradeStep,
 )
 from cou.utils.app_utils import upgrade_packages
-from cou.utils.juju_utils import COUModel
+from cou.utils.juju_utils import COUModel, Machine
 from cou.utils.openstack import (
     DISTRO_TO_OPENSTACK_MAPPING,
     OpenStackCodenameLookup,
@@ -59,8 +59,8 @@ class ApplicationUnit:
 
     name: str
     os_version: OpenStackRelease
+    machine: Machine
     workload_version: str = ""
-    machine: str = ""
 
 
 @dataclass
@@ -77,6 +77,8 @@ class OpenStackApplication:
     :type model: COUModel
     :param charm: Name of the charm.
     :type charm: str
+    :param machines: dictionary with Machine
+    :type machines: dict[str, Machine]
     :param units: Units representation of an application.
     :type units: list[ApplicationUnit]
     :raises ApplicationError: When there are no compatible OpenStack release for the
@@ -95,6 +97,7 @@ class OpenStackApplication:
     config: dict
     model: COUModel
     charm: str
+    machines: dict[str, Machine]
     units: list[ApplicationUnit] = field(default_factory=lambda: [])
     packages_to_hold: Optional[list] = field(default=None, init=False)
     wait_timeout: int = field(default=STANDARD_IDLE_TIMEOUT, init=False)
@@ -177,7 +180,7 @@ def _populate_units(self) -> None:
                         name=name,
                         workload_version=unit.workload_version,
                         os_version=compatible_os_version,
-                        machine=unit.machine,
+                        machine=self.machines[unit.machine],
                     )
                 )
 
@@ -390,16 +393,8 @@ def channel_codename(self) -> OpenStackRelease:
         :return: OpenStackRelease object
         :rtype: OpenStackRelease
         """
-        try:
-            # get the OpenStack release from the channel track of the application.
-            os_track_release_channel = OpenStackRelease(self._get_track_from_channel(self.channel))
-        except ValueError:
-            logger.debug(
-                "The current channel of '%s' does not exist or is unexpectedly formatted",
-                self.name,
-            )
-            os_track_release_channel = self.current_os_release
-        return os_track_release_channel
+        # get the OpenStack release from the channel track of the application.
+        return OpenStackRelease(self._get_track_from_channel(self.channel))
 
     @property
     def can_upgrade_current_channel(self) -> bool:

cou/apps/factory.py

@@ -22,7 +22,7 @@
 from juju.client._definitions import ApplicationStatus
 
 from cou.apps.base import OpenStackApplication
-from cou.utils.juju_utils import COUModel
+from cou.utils.juju_utils import COUModel, Machine
 from cou.utils.openstack import is_charm_supported
 
 logger = logging.getLogger(__name__)
@@ -41,13 +41,16 @@ def create(
         config: dict,
         model: COUModel,
         charm: str,
+        machines: dict[str, Machine],
     ) -> Optional[OpenStackApplication]:
         """Create the OpenStackApplication or registered subclasses.
 
         Applications Subclasses registered with the "register_application"
         decorator can be instantiated and used with their customized methods.
         :param name: Name of the application
         :type name: str
+        :param machines: Machines in the model
+        :type machines: dict[str, Machine]
         :param status: Status of the application
         :type status: ApplicationStatus
         :param config: Configuration of the application
@@ -62,7 +65,14 @@ def create(
         # pylint: disable=too-many-arguments
         if is_charm_supported(charm):
             app_class = cls.charms.get(charm, OpenStackApplication)
-            return app_class(name=name, status=status, config=config, model=model, charm=charm)
+            return app_class(
+                name=name,
+                status=status,
+                config=config,
+                model=model,
+                charm=charm,
+                machines=machines,
+            )
         logger.debug(
             "'%s' is not a supported OpenStack related application and will be ignored.",
             name,

cou/steps/analyze.py

@@ -121,13 +121,18 @@ async def _populate(cls, model: juju_utils.COUModel) -> list[OpenStackApplicatio
         :rtype: List[OpenStackApplication]
         """
         juju_status = await model.get_status()
+        juju_machines = await model.get_machines()
         apps = {
             AppFactory.create(
                 name=app,
                 status=app_status,
                 config=await model.get_application_config(app),
                 model=model,
                 charm=await model.get_charm_name(app),
+                machines={
+                    unit_status.machine: juju_machines[unit_status.machine]
+                    for unit_status in app_status.units.values()
+                },
             )
             for app, app_status in juju_status.applications.items()
             if app_status

cou/utils/juju_utils.py

@@ -16,6 +16,7 @@
 import asyncio
 import logging
 import os
+from dataclasses import dataclass
 from datetime import datetime
 from typing import Any, Callable, Optional
 
@@ -129,6 +130,15 @@ async def wrapper(*args: Any, **kwargs: Any) -> Any:  # pylint: disable=W9011
     return _wrapper
 
 
+@dataclass(frozen=True)
+class Machine:
+    """Representation of a juju machine."""
+
+    machine_id: str
+    apps: tuple[str]
+    az: Optional[str] = None  # simple deployments may not have azs
+
+
 class COUModel:
     """COU model object.
 
@@ -499,3 +509,24 @@ async def _wait_for_active_idle() -> None:
             apps = await self._get_supported_apps()
 
         await _wait_for_active_idle()
+
+    async def get_machines(self) -> dict[str, Machine]:
+        """Get all the machines in the model.
+
+        :return: Dictionary of the machines found in the model. E.g: {'0': Machine0}
+        :rtype: dict[str, Machine]
+        """
+        model = await self._get_model()
+
+        return {
+            machine.id: Machine(
+                machine_id=machine.id,
+                apps=tuple(
+                    unit.application
+                    for unit in self._model.units.values()
+                    if unit.machine.id == machine.id
+                ),
+                az=machine.hardware_characteristics.get("availability-zone"),
+            )
+            for machine in model.machines.values()
+        }