From d68dec3b906bd200f7041744cf22a001c13150e8 Mon Sep 17 00:00:00 2001
From: Mike Graves <mgraves@redhat.com>
Date: Fri, 11 Mar 2022 12:32:12 -0500
Subject: [PATCH] Fix waiting on StatefulSet scale down (#391)
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Fix waiting on StatefulSet scale down

SUMMARY

When scaling a StatefulSet down to 0 replicas the wait will fail
because some properties of the status (readyReplicas, updatedReplicas)
will not exist. These are probably defined as omitempty in the API and
since the value is zero are not present in the response.

Fixes #203
ISSUE TYPE


Bugfix Pull Request

COMPONENT NAME

k8s_scale
ADDITIONAL INFORMATION

Reviewed-by: Gonéri Le Bouder <goneri@lebouder.net>
---
 .../fragments/391-fix-statefulset-wait.yaml   |  2 +
 plugins/module_utils/common.py                |  8 +++-
 .../targets/k8s_scale/tasks/main.yml          | 48 +++++++++++++++++++
 3 files changed, 56 insertions(+), 2 deletions(-)
 create mode 100644 changelogs/fragments/391-fix-statefulset-wait.yaml

diff --git a/changelogs/fragments/391-fix-statefulset-wait.yaml b/changelogs/fragments/391-fix-statefulset-wait.yaml
new file mode 100644
index 00000000..2fe84d84
--- /dev/null
+++ b/changelogs/fragments/391-fix-statefulset-wait.yaml
@@ -0,0 +1,2 @@
+bugfixes:
+  - k8s_scale - fix waiting on statefulset when scaled down to 0 replicas (https://github.com/ansible-collections/kubernetes.core/issues/203).
diff --git a/plugins/module_utils/common.py b/plugins/module_utils/common.py
index 9fec2f77..51343a9b 100644
--- a/plugins/module_utils/common.py
+++ b/plugins/module_utils/common.py
@@ -633,6 +633,10 @@ class K8sAnsibleMixin(object):
             )
 
         def _statefulset_ready(statefulset):
+            # These may be None
+            updated_replicas = statefulset.status.updatedReplicas or 0
+            ready_replicas = statefulset.status.readyReplicas or 0
+
             return (
                 statefulset.status
                 and statefulset.spec.updateStrategy.type == "RollingUpdate"
@@ -640,8 +644,8 @@ class K8sAnsibleMixin(object):
                 == (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 updated_replicas == statefulset.spec.replicas
+                and ready_replicas == statefulset.spec.replicas
                 and statefulset.status.replicas == statefulset.spec.replicas
             )
 
diff --git a/tests/integration/targets/k8s_scale/tasks/main.yml b/tests/integration/targets/k8s_scale/tasks/main.yml
index 81e2146e..d58a01bc 100644
--- a/tests/integration/targets/k8s_scale/tasks/main.yml
+++ b/tests/integration/targets/k8s_scale/tasks/main.yml
@@ -341,6 +341,54 @@
           - scale_out.changed
           - scale_out.results | map(attribute='result.status.replicas') | list | unique == [2]
 
+    - name: Create a StatefulSet
+      kubernetes.core.k8s:
+        wait: yes
+        wait_timeout: "{{ k8s_wait_timeout | default(omit) }}"
+        definition:
+          apiVersion: apps/v1
+          kind: StatefulSet
+          metadata:
+            namespace: "{{ scale_namespace }}"
+            name: scale-set
+          spec:
+            replicas: 2
+            selector:
+              matchLabels:
+                app: foo
+            template:
+              metadata:
+                labels:
+                  app: foo
+              spec:
+                terminationGracePeriodSeconds: 10
+                containers:
+                  - image: busybox
+                    name: busybox
+                    command:
+                      - sleep
+                      - "600"
+      register: output
+
+    - assert:
+        that:
+          - output.result.status.replicas == 2
+
+    - name: Wait for StatefulSet to scale down to 0
+      kubernetes.core.k8s_scale:
+        kind: StatefulSet
+        api_version: apps/v1
+        name: scale-set
+        namespace: "{{ scale_namespace }}"
+        replicas: 0
+        wait: yes
+        wait_timeout: "{{ k8s_wait_timeout | default(omit) }}"
+      register: output
+
+    - assert:
+        that:
+          - output.result.status.replicas == 0
+
   always:
     - name: Remove namespace
       k8s: