Clean remote application when disabling observability

Clean remote applications coming from observability model when disabling
observability plugin.

LP: 2063183

sunbeam-python/sunbeam/plugins/observability/plugin.py

@@ -30,7 +30,7 @@
 from sunbeam.clusterd.service import ClusterServiceUnavailableException
 from sunbeam.commands.juju import JujuStepHelper
 from sunbeam.commands.k8s import CREDENTIAL_SUFFIX, K8SHelper
-from sunbeam.commands.openstack import PatchLoadBalancerServicesStep
+from sunbeam.commands.openstack import OPENSTACK_MODEL, PatchLoadBalancerServicesStep
 from sunbeam.commands.terraform import TerraformException, TerraformInitStep
 from sunbeam.jobs.common import (
     BaseStep,
@@ -178,6 +178,52 @@ def run(self, status: Optional[Status] = None) -> Result:
         return Result(ResultType.COMPLETED)
 
 
+class RemoveSaasApplicationsStep(BaseStep):
+    """Removes SAAS offers from given model."""
+
+    def __init__(self, jhelper: JujuHelper, model: str, offering_model: str):
+        super().__init__(
+            f"Purge SAAS Offers: {model}", f"Purging SAAS Offers from {model}"
+        )
+        self.jhelper = jhelper
+        self.model = model
+        self.offering_model = offering_model
+        self._remote_app_to_delete = []
+
+    def is_skip(self, status: Status | None = None) -> Result:
+        model = run_sync(self.jhelper.get_model(self.model))
+        remote_application = model.remote_applications
+        LOG.debug("Remote applications found: %s", ", ".join(remote_application.keys()))
+        if not remote_application:
+            return Result(ResultType.SKIPPED, "No remote applications found")
+
+        for name, remote_app in remote_application.items():
+            if not remote_app:
+                continue
+            offer = remote_app.offer_url
+            LOG.debug("Processing offer: %s", offer)
+            model_name = offer.split("/", 1)[1].split(".", 1)[0]
+            if model_name == self.offering_model:
+                self._remote_app_to_delete.append(name)
+
+        if len(self._remote_app_to_delete) == 0:
+            return Result(ResultType.SKIPPED, "No remote applications to remove")
+
+        return Result(ResultType.COMPLETED)
+
+    def run(self, status: Optional[Status] = None) -> Result:
+        """Execute configuration using terraform."""
+        if not self._remote_app_to_delete:
+            return Result(ResultType.COMPLETED)
+
+        model = run_sync(self.jhelper.get_model(self.model))
+
+        for saas in self._remote_app_to_delete:
+            LOG.debug("Removing remote application %s", saas)
+            run_sync(model.remove_saas(saas))
+        return Result(ResultType.COMPLETED)
+
+
 class DeployGrafanaAgentStep(BaseStep, JujuStepHelper):
     """Deploy Grafana Agent using Terraform"""
 
@@ -515,11 +561,15 @@ def run_disable_plans(self):
         agent_grafana_k8s_plan = [
             TerraformInitStep(self.manifest.get_tfhelper(self.tfplan)),
             DisableOpenStackApplicationStep(jhelper, self),
+            RemoveSaasApplicationsStep(jhelper, OPENSTACK_MODEL, OBSERVABILITY_MODEL),
         ]
 
         grafana_agent_plan = [
             TerraformInitStep(self.manifest.get_tfhelper(self.tfplan_grafana_agent)),
             RemoveGrafanaAgentStep(self, jhelper),
+            RemoveSaasApplicationsStep(
+                jhelper, self.deployment.infrastructure_model, OBSERVABILITY_MODEL
+            ),
         ]
 
         cos_plan = [

sunbeam-python/tests/unit/sunbeam/plugins/test_observability.py

@@ -13,7 +13,7 @@
 # limitations under the License.
 
 import asyncio
-from unittest.mock import AsyncMock, patch
+from unittest.mock import AsyncMock, Mock, patch
 
 import pytest
 
@@ -222,3 +222,45 @@ def test_run_waiting_timed_out(self, jhelper, observabilityplugin):
         jhelper.wait_application_gone.assert_called_once()
         assert result.result_type == ResultType.FAILED
         assert result.message == "timed out"
+
+
+class TestRemoveSaasApplicationsStep:
+    def test_is_skip(self, jhelper):
+        jhelper.get_model.return_value = AsyncMock(
+            remote_applications={
+                "test-1": Mock(offer_url="admin/offering_model.test-1")
+            }
+        )
+        step = observability_plugin.RemoveSaasApplicationsStep(
+            jhelper, "test", "offering_model"
+        )
+        result = step.is_skip()
+        assert result.result_type == ResultType.COMPLETED
+
+    def test_is_skip_no_remote_app(self, jhelper):
+        jhelper.get_model.return_value = AsyncMock(remote_applications={})
+        step = observability_plugin.RemoveSaasApplicationsStep(
+            jhelper, "test", "offering_model"
+        )
+        result = step.is_skip()
+        assert result.result_type == ResultType.SKIPPED
+
+    def test_is_skip_no_saas_app(self, jhelper):
+        jhelper.get_model.return_value = AsyncMock(
+            remote_applications={
+                "test-1": Mock(offer_url="admin/offering_model.test-1")
+            }
+        )
+        step = observability_plugin.RemoveSaasApplicationsStep(
+            jhelper, "test", "offering_model-no-apps"
+        )
+        result = step.is_skip()
+        assert result.result_type == ResultType.SKIPPED
+
+    def test_run(self, jhelper):
+        step = observability_plugin.RemoveSaasApplicationsStep(
+            jhelper, "test", "offering_model"
+        )
+        step._remote_app_to_delete = ["test-1"]
+        result = step.run()
+        assert result.result_type == ResultType.COMPLETED