Merge pull request #49688 from wojtek-t/skip_cacher_if_not_initialized

Automatic merge from submit-queue (batch tested with PRs 49581, 49652, 49681, 49688, 44655)

Don't use cacher if uninitialized

Ref #49684

staging/src/k8s.io/apiserver/pkg/storage/cacher.go

@@ -369,6 +369,12 @@ func (c *Cacher) Get(ctx context.Context, key string, resourceVersion string, ob
 		return err
 	}
 
+	if getRV == 0 && !c.ready.check() {
+		// If Cacher is not yet initialized and we don't require any specific
+		// minimal resource version, simply forward the request to storage.
+		return c.storage.Get(ctx, key, resourceVersion, objPtr, ignoreNotFound)
+	}
+
 	// Do not create a trace - it's not for free and there are tons
 	// of Get requests. We can add it if it will be really needed.
 	c.ready.wait()
@@ -414,6 +420,12 @@ func (c *Cacher) GetToList(ctx context.Context, key string, resourceVersion stri
 		return err
 	}
 
+	if listRV == 0 && !c.ready.check() {
+		// If Cacher is not yet initialized and we don't require any specific
+		// minimal resource version, simply forward the request to storage.
+		return c.storage.GetToList(ctx, key, resourceVersion, pred, listObj)
+	}
+
 	trace := utiltrace.New(fmt.Sprintf("cacher %v: List", c.objectType.String()))
 	defer trace.LogIfLong(500 * time.Millisecond)
 
@@ -470,6 +482,12 @@ func (c *Cacher) List(ctx context.Context, key string, resourceVersion string, p
 		return err
 	}
 
+	if listRV == 0 && !c.ready.check() {
+		// If Cacher is not yet initialized and we don't require any specific
+		// minimal resource version, simply forward the request to storage.
+		return c.storage.List(ctx, key, resourceVersion, pred, listObj)
+	}
+
 	trace := utiltrace.New(fmt.Sprintf("cacher %v: List", c.objectType.String()))
 	defer trace.LogIfLong(500 * time.Millisecond)
 
@@ -966,6 +984,14 @@ func (r *ready) wait() {
 	r.c.L.Unlock()
 }
 
+// TODO: Make check() function more sophisticated, in particular
+// allow it to behave as "waitWithTimeout".
+func (r *ready) check() bool {
+	r.c.L.Lock()
+	defer r.c.L.Unlock()
+	return r.ok
+}
+
 func (r *ready) set(ok bool) {
 	r.c.L.Lock()
 	defer r.c.L.Unlock()