From 3853a9b77db211762716a1cf48588de8edfa8442 Mon Sep 17 00:00:00 2001
From: James Peach <jpeach@vmware.com>
Date: Wed, 29 Jul 2020 01:10:41 +1000
Subject: [PATCH] Sync the informer cache on each test. (#9)

This change should have been made a long time ago. On test start up,
sync the informer caches right before we start to run any checks. This
ensures that cluster precondition checks are reliable.

Signed-off-by: James Peach <jpeach@vmware.com>
---
 pkg/driver/object.go | 22 ++++++++++++++++++++++
 pkg/test/runner.go   | 11 +++++++++--
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/pkg/driver/object.go b/pkg/driver/object.go
index 667a5df..9091a81 100644
--- a/pkg/driver/object.go
+++ b/pkg/driver/object.go
@@ -73,6 +73,10 @@ type ObjectDriver interface {
 	// watchers.
 	InformOn(gvr schema.GroupVersionResource) error
 
+	// WaitForCacheSync waits until all the informers created
+	// by the driver have synced.
+	WaitForCacheSync(timeout time.Duration) error
+
 	// Watch registers an event handler to receive events from
 	// all the informers managed by the driver.
 	Watch(cache.ResourceEventHandler) func()
@@ -217,6 +221,24 @@ func (o *objectDriver) InformOn(gvr schema.GroupVersionResource) error {
 	return nil
 }
 
+func (o *objectDriver) WaitForCacheSync(timeout time.Duration) error {
+	var synced []cache.InformerSynced
+
+	for _, i := range o.informerPool {
+		synced = append(synced, i.Informer().HasSynced)
+	}
+
+	stopChan := make(chan struct{})
+	timer := time.AfterFunc(timeout, func() { close(stopChan) })
+	defer timer.Stop()
+
+	if !cache.WaitForCacheSync(stopChan, synced...) {
+		return errors.New("informer cache sync timed out")
+	}
+
+	return nil
+}
+
 func (o *objectDriver) Apply(obj *unstructured.Unstructured) (*OperationResult, error) {
 	obj = obj.DeepCopy() // Copy in case we set the namespace.
 	gvk := obj.GetObjectKind().GroupVersionKind()
diff --git a/pkg/test/runner.go b/pkg/test/runner.go
index 68f9bd3..14db8e5 100644
--- a/pkg/test/runner.go
+++ b/pkg/test/runner.go
@@ -92,14 +92,14 @@ func PreserveObjectsOpt() RunOpt {
 	})
 }
 
-// WatchResourceOpt disables automatic object deletion.
+// WatchResourceOpt adds an explicit informer for the given resource.
 func WatchResourceOpt(gvr schema.GroupVersionResource) RunOpt {
 	return RunOpt(func(tc *testContext) {
 		tc.watchedResources = append(tc.watchedResources, gvr)
 	})
 }
 
-// DryRunOpt enables Kuberentes dry-run mode (TODO).
+// DryRunOpt enables Kubernetes dry-run mode (TODO).
 func DryRunOpt() RunOpt {
 	return RunOpt(func(tc *testContext) {
 		tc.dryRun = true
@@ -188,6 +188,13 @@ func Run(testDoc *doc.Document, opts ...RunOpt) error {
 		tc.objectDriver.InformOn(gvr)
 	}
 
+	// Let the informers sync. For most environments, this
+	// timeout is far too long. Eventually we can make it a flag
+	// to tune it down.
+	if err := tc.objectDriver.WaitForCacheSync(5 * time.Minute); err != nil {
+		return err
+	}
+
 	if err := storeResourceVersions(tc.kubeDriver, tc.regoDriver); err != nil {
 		return err
 	}