pkg/k8sutil: Add utility function for getting a node with retry. Add a generic retry function that retries on any error.

Author: hankjacobs

pkg/k8sutil/metadata.go

@@ -35,6 +35,22 @@ func NodeAnnotationCondition(selector fields.Selector) watch.ConditionFunc {
 	}
 }
 
+// GetNodeRetry gets a node object, retrying up to DefaultBackoff number of times if it fails
+func GetNodeRetry(nc v1core.NodeInterface, node string) (*v1api.Node, error) {
+	var apiNode *v1api.Node
+	err := RetryOnError(DefaultBackoff, func() error {
+		n, getErr := nc.Get(node, v1meta.GetOptions{})
+		if getErr != nil {
+			return fmt.Errorf("failed to get node %q: %v", node, getErr)
+		}
+
+		apiNode = n
+		return nil
+	})
+
+	return apiNode, err
+}
+
 // UpdateNodeRetry calls f to update a node object in Kubernetes.
 // It will attempt to update the node by applying f to it up to DefaultBackoff
 // number of times.

pkg/k8sutil/retry.go

@@ -79,3 +79,21 @@ func RetryOnConflict(backoff wait.Backoff, fn func() error) error {
 	}
 	return err
 }
+
+// RetryOnError retries a function repeatedly with the specified backoff until it succeeds or times out
+func RetryOnError(backoff wait.Backoff, fn func() error) error {
+	var lastErr error
+	err := wait.ExponentialBackoff(backoff, func() (bool, error) {
+		lastErr := fn()
+		if lastErr == nil {
+			return true, nil
+		}
+
+		return false, nil
+	})
+
+	if err == wait.ErrWaitTimeout {
+		err = lastErr
+	}
+	return err
+}