From e153b8a3df1be332862bfa1666ec8c4a0cfa71fe Mon Sep 17 00:00:00 2001
From: sopida-chotwanwirach <sopida.chotwanwirach@offerup.com>
Date: Wed, 13 Mar 2024 17:22:05 -0700
Subject: [PATCH] fix(gloo): Update reconciler to detect change in gloo
 upstream spec Signed-off-by: sopida-chotwanwirach
 <sopida.chotwanwirach@offerup.com>

---
 pkg/router/gloo.go       | 33 +++++++++++++++++++++++++++++++-
 test/gloo/test-canary.sh | 41 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+), 1 deletion(-)

diff --git a/pkg/router/gloo.go b/pkg/router/gloo.go
index 23658145c..b8a415280 100644
--- a/pkg/router/gloo.go
+++ b/pkg/router/gloo.go
@@ -275,7 +275,8 @@ func (gr *GlooRouter) createFlaggerUpstream(canary *flaggerv1.Canary, upstreamNa
 	if err != nil {
 		return fmt.Errorf("service %s.%s get query error: %w", svcName, canary.Namespace, err)
 	}
-	_, err = upstreamClient.Get(context.TODO(), upstreamName, metav1.GetOptions{})
+	curUpstream, err := upstreamClient.Get(context.TODO(), upstreamName, metav1.GetOptions{})
+
 	if errors.IsNotFound(err) {
 		glooUpstreamWithConfig, err := gr.getGlooConfigUpstream(canary)
 		if err != nil {
@@ -288,7 +289,37 @@ func (gr *GlooRouter) createFlaggerUpstream(canary *flaggerv1.Canary, upstreamNa
 		}
 	} else if err != nil {
 		return fmt.Errorf("upstream %s.%s get query error: %w", upstreamName, canary.Namespace, err)
+	} else {
+		return gr.syncUpstreamSpec(curUpstream, canary)
+	}
+	return nil
+}
+
+func (gr *GlooRouter) syncUpstreamSpec(curUpstream *gloov1.Upstream, canary *flaggerv1.Canary) error {
+	glooUpstreamWithConfig, err := gr.getGlooConfigUpstream(canary)
+	if err != nil {
+		return err
+	}
+
+	if glooUpstreamWithConfig == nil {
+		return nil
 	}
+
+	glooUpstreamLB := glooUpstreamWithConfig.Spec.LoadBalancerConfig
+	loadBalancerDiff := cmp.Diff(glooUpstreamLB, curUpstream.Spec.LoadBalancerConfig)
+
+	if loadBalancerDiff != "" {
+		gr.logger.Debugf("detect diff in upstream spec %s.%s %s", curUpstream.Name, canary.Namespace, loadBalancerDiff)
+
+		cloneUpstream := curUpstream.DeepCopy()
+		cloneUpstream.Spec.LoadBalancerConfig = glooUpstreamLB
+
+		_, err = gr.glooClient.GlooV1().Upstreams(canary.Namespace).Update(context.TODO(), cloneUpstream, metav1.UpdateOptions{})
+		if err != nil {
+			return fmt.Errorf("upstream %s.%s spec update error: %w", curUpstream.Name, canary.Namespace, err)
+		}
+	}
+
 	return nil
 }
 
diff --git a/test/gloo/test-canary.sh b/test/gloo/test-canary.sh
index f3afd257b..047c58b9f 100755
--- a/test/gloo/test-canary.sh
+++ b/test/gloo/test-canary.sh
@@ -117,6 +117,47 @@ done
 
 echo '✔ Canary initialization test passed'
 
+echo '>>> Waiting for primary spec to be updated'
+
+# Update gloo upstream on slow start config which will trigger update on flagger upstreams
+cat <<EOF | kubectl apply -f -
+apiVersion: gloo.solo.io/v1
+kind: Upstream
+metadata:
+  name: config-upstream
+  namespace: gloo-system
+spec:
+  static:
+    hosts:
+    - addr: "example.com"
+      port: 80
+  connectionConfig:
+    connectTimeout: 2s
+    maxRequestsPerConnection: 51
+  loadBalancerConfig:
+    roundRobin:
+      slowStartConfig:
+        slowStartWindow: 2m
+        minWeightPercent: 20
+EOF
+
+retries=50
+count=0
+ok=false
+until ${ok}; do
+    kubectl -n test get upstream/test-podinfo-canaryupstream-80 -ojson | jq '.spec.loadBalancerConfig.roundRobin.slowStartConfig.minWeightPercent' | grep '20' && ok=true || ok=false
+    
+    sleep 5
+    count=$(($count + 1))
+    if [[ ${count} -eq ${retries} ]]; then
+        kubectl -n gloo-system logs deployment/flagger
+        echo "No more retries left"
+        exit 1
+    fi
+done
+
+echo '✔ Canary reconcilation test passed'
+
 echo '>>> Triggering canary deployment'
 kubectl -n test set image deployment/podinfo podinfod=ghcr.io/stefanprodan/podinfo:6.0.1