From 01519369f2d9b4c2c21b8157987da1d9f994918d Mon Sep 17 00:00:00 2001
From: Ian Booth <ian.booth@canonical.com>
Date: Mon, 22 Apr 2024 10:09:50 +1000
Subject: [PATCH] Do not render empty pod affinity info

---
 .../provider/application/constraints.go       | 25 +++++++++++--------
 .../provider/application/constraints_test.go  | 12 +++++++++
 2 files changed, 27 insertions(+), 10 deletions(-)

diff --git a/caas/kubernetes/provider/application/constraints.go b/caas/kubernetes/provider/application/constraints.go
index b3120f7c45f..68450f3d13c 100644
--- a/caas/kubernetes/provider/application/constraints.go
+++ b/caas/kubernetes/provider/application/constraints.go
@@ -159,13 +159,15 @@ func processNodeAffinity(pod *core.PodSpec, affinityLabels map[string]string) er
 	}
 	var nodeSelectorTerm core.NodeSelectorTerm
 	updateSelectorTerms(&nodeSelectorTerm, affinityTags)
-	if pod.Affinity == nil {
-		pod.Affinity = &core.Affinity{}
-	}
-	pod.Affinity.NodeAffinity = &core.NodeAffinity{
-		RequiredDuringSchedulingIgnoredDuringExecution: &core.NodeSelector{
-			NodeSelectorTerms: []core.NodeSelectorTerm{nodeSelectorTerm},
-		},
+	if len(nodeSelectorTerm.MatchExpressions) > 0 {
+		if pod.Affinity == nil {
+			pod.Affinity = &core.Affinity{}
+		}
+		pod.Affinity.NodeAffinity = &core.NodeAffinity{
+			RequiredDuringSchedulingIgnoredDuringExecution: &core.NodeSelector{
+				NodeSelectorTerms: []core.NodeSelectorTerm{nodeSelectorTerm},
+			},
+		}
 	}
 	return nil
 }
@@ -240,12 +242,12 @@ func processPodAffinity(pod *core.PodSpec, affinityLabels map[string]string) err
 			affinityTerm.TopologyKey = topologyKey
 		}
 	}
-	if pod.Affinity == nil {
-		pod.Affinity = &core.Affinity{}
-	}
 	var affinityTerm core.PodAffinityTerm
 	updateAffinityTerm(&affinityTerm, affinityTags)
 	if len(affinityTerm.LabelSelector.MatchExpressions) > 0 || affinityTerm.TopologyKey != "" {
+		if pod.Affinity == nil {
+			pod.Affinity = &core.Affinity{}
+		}
 		pod.Affinity.PodAffinity = &core.PodAffinity{
 			RequiredDuringSchedulingIgnoredDuringExecution: []core.PodAffinityTerm{affinityTerm},
 		}
@@ -254,6 +256,9 @@ func processPodAffinity(pod *core.PodSpec, affinityLabels map[string]string) err
 	var antiAffinityTerm core.PodAffinityTerm
 	updateAffinityTerm(&antiAffinityTerm, antiAffinityTags)
 	if len(antiAffinityTerm.LabelSelector.MatchExpressions) > 0 || antiAffinityTerm.TopologyKey != "" {
+		if pod.Affinity == nil {
+			pod.Affinity = &core.Affinity{}
+		}
 		pod.Affinity.PodAntiAffinity = &core.PodAntiAffinity{
 			RequiredDuringSchedulingIgnoredDuringExecution: []core.PodAffinityTerm{antiAffinityTerm},
 		}
diff --git a/caas/kubernetes/provider/application/constraints_test.go b/caas/kubernetes/provider/application/constraints_test.go
index ce39bb93c58..814e9a2863f 100644
--- a/caas/kubernetes/provider/application/constraints_test.go
+++ b/caas/kubernetes/provider/application/constraints_test.go
@@ -69,6 +69,8 @@ func (s *applyConstraintsSuite) TestPodAffinityJustTopologyKey(c *gc.C) {
 			TopologyKey:   "foo",
 		}},
 	})
+	c.Assert(pod.Affinity.PodAntiAffinity, gc.IsNil)
+	c.Assert(pod.Affinity.NodeAffinity, gc.IsNil)
 }
 
 func (s *applyConstraintsSuite) TestAffinityPod(c *gc.C) {
@@ -94,6 +96,8 @@ func (s *applyConstraintsSuite) TestAffinityPod(c *gc.C) {
 			},
 		}},
 	})
+	c.Assert(pod.Affinity.PodAntiAffinity, gc.IsNil)
+	c.Assert(pod.Affinity.NodeAffinity, gc.IsNil)
 }
 
 func (s *applyConstraintsSuite) TestPodAffinityAll(c *gc.C) {
@@ -135,6 +139,8 @@ func (s *applyConstraintsSuite) TestAntiPodAffinityJustTopologyKey(c *gc.C) {
 			TopologyKey:   "foo",
 		}},
 	})
+	c.Assert(pod.Affinity.PodAffinity, gc.IsNil)
+	c.Assert(pod.Affinity.NodeAffinity, gc.IsNil)
 }
 
 func (s *applyConstraintsSuite) TestAntiPodAffinity(c *gc.C) {
@@ -160,6 +166,8 @@ func (s *applyConstraintsSuite) TestAntiPodAffinity(c *gc.C) {
 			},
 		}},
 	})
+	c.Assert(pod.Affinity.PodAffinity, gc.IsNil)
+	c.Assert(pod.Affinity.NodeAffinity, gc.IsNil)
 }
 
 func (s *applyConstraintsSuite) TestAntiPodAffinityAll(c *gc.C) {
@@ -186,6 +194,8 @@ func (s *applyConstraintsSuite) TestAntiPodAffinityAll(c *gc.C) {
 			TopologyKey: "foo",
 		}},
 	})
+	c.Assert(pod.Affinity.PodAffinity, gc.IsNil)
+	c.Assert(pod.Affinity.NodeAffinity, gc.IsNil)
 }
 
 func (s *applyConstraintsSuite) TestNodeAntiAffinity(c *gc.C) {
@@ -210,4 +220,6 @@ func (s *applyConstraintsSuite) TestNodeAntiAffinity(c *gc.C) {
 			}},
 		},
 	})
+	c.Assert(pod.Affinity.PodAffinity, gc.IsNil)
+	c.Assert(pod.Affinity.PodAntiAffinity, gc.IsNil)
 }