Add support for waiting on a StatefulSet. (#195)

Add support for waiting on a StatefulSet.

SUMMARY
This PR implements support for waiting on StatefulSet for readiness similar to how the other waiters currently work.
ISSUE TYPE

Feature Pull Request

ADDITIONAL INFORMATION
This was designed to (mostly) mimic the behaviour of the StatefulSetStatusViewer used by kubectl rollout status -w.

Reviewed-by: Abhijeet Kasurde <None>
Reviewed-by: Joshua K <None>
Reviewed-by: None <None>
Reviewed-by: Mike Graves <mgraves@redhat.com>
Reviewed-by: None <None>

changelogs/fragments/195-k8s-add-wait-statefulsets.yml

@@ -0,0 +1,2 @@
+minor_changes:
+  - k8s - add support for waiting on statefulsets (https://github.com/ansible-collections/kubernetes.core/pull/195).

molecule/default/tasks/waiter.yml

@@ -140,6 +140,111 @@
           - ds.result.status.currentNumberScheduled == ds.result.status.desiredNumberScheduled
           - updated_ds_pods.resources[0].spec.containers[0].image.endswith(":3")
 
+    - name: Add a statefulset
+      k8s:
+        definition:
+          apiVersion: apps/v1
+          kind: StatefulSet
+          metadata:
+            name: wait-statefulset
+            namespace: "{{ wait_namespace }}"
+          spec:
+            selector:
+              matchLabels:
+                app: "{{ k8s_pod_name }}"
+            template: "{{ k8s_pod_template }}"
+        wait: yes
+        wait_sleep: 5
+        wait_timeout: 180
+      vars:
+        k8s_pod_name: wait-sts
+        k8s_pod_image: gcr.io/kuar-demo/kuard-amd64:1
+        k8s_pod_command:
+          - sleep
+          - "600"
+      register: sts
+
+    - name: Check that statefulset wait worked
+      assert:
+        that:
+          - sts.result.spec.replicas == sts.result.status.readyReplicas
+
+    - name: Update a statefulset in check_mode
+      k8s:
+        definition:
+          apiVersion: apps/v1
+          kind: StatefulSet
+          metadata:
+            name: wait-statefulset
+            namespace: "{{ wait_namespace }}"
+          spec:
+            selector:
+              matchLabels:
+                app: "{{ k8s_pod_name }}"
+            updateStrategy:
+              type: RollingUpdate
+            template: "{{ k8s_pod_template }}"
+        wait: yes
+        wait_sleep: 3
+        wait_timeout: 180
+      vars:
+        k8s_pod_name: wait-sts
+        k8s_pod_image: gcr.io/kuar-demo/kuard-amd64:2
+        k8s_pod_command:
+          - sleep
+          - "600"
+      register: update_sts_check_mode
+      check_mode: yes
+
+    - name: Check that check_mode result contains the changes
+      assert:
+        that:
+          - update_sts_check_mode is changed
+          - "update_sts_check_mode.result.spec.template.spec.containers[0].image == 'gcr.io/kuar-demo/kuard-amd64:2'"
+
+    - name: Update a statefulset
+      k8s:
+        definition:
+          apiVersion: apps/v1
+          kind: StatefulSet
+          metadata:
+            name: wait-statefulset
+            namespace: "{{ wait_namespace }}"
+          spec:
+            selector:
+              matchLabels:
+                app: "{{ k8s_pod_name }}"
+            updateStrategy:
+              type: RollingUpdate
+            template: "{{ k8s_pod_template }}"
+        wait: yes
+        wait_sleep: 3
+        wait_timeout: 180
+      vars:
+        k8s_pod_name: wait-sts
+        k8s_pod_image: gcr.io/kuar-demo/kuard-amd64:3
+        k8s_pod_command:
+          - sleep
+          - "600"
+      register: sts
+
+    - name: Get updated pods
+      k8s_info:
+        api_version: v1
+        kind: Pod
+        namespace: "{{ wait_namespace }}"
+        label_selectors:
+          - app=wait-sts
+        field_selectors:
+          - status.phase=Running
+      register: updated_sts_pods
+
+    - name: Check that statefulset wait worked
+      assert:
+        that:
+          - sts.result.spec.replicas == sts.result.status.readyReplicas
+          - updated_sts_pods.resources[0].spec.containers[0].image.endswith(":3")
+
     - name: Add a crashing pod
       k8s:
         definition:

plugins/module_utils/common.py

@@ -401,6 +401,14 @@ class K8sAnsibleMixin(object):
                     and daemonset.status.observedGeneration == daemonset.metadata.generation
                     and not daemonset.status.unavailableReplicas)
 
+        def _statefulset_ready(statefulset):
+            return (statefulset.status and statefulset.spec.updateStrategy.type == "RollingUpdate"
+                    and statefulset.status.observedGeneration == (statefulset.metadata.generation or 0)
+                    and statefulset.status.updateRevision == statefulset.status.currentRevision
+                    and statefulset.status.updatedReplicas == statefulset.spec.replicas
+                    and statefulset.status.readyReplicas == statefulset.spec.replicas
+                    and statefulset.status.replicas == statefulset.spec.replicas)
+
         def _custom_condition(resource):
             if not resource.status or not resource.status.conditions:
                 return False
@@ -427,6 +435,7 @@ class K8sAnsibleMixin(object):
             return not resource or (resource.kind.endswith('List') and resource.items == [])
 
         waiter = dict(
+            StatefulSet=_statefulset_ready,
             Deployment=_deployment_ready,
             DaemonSet=_daemonset_ready,
             Pod=_pod_ready