vendor files

vendor/k8s.io/kubernetes/pkg/kubelet/kubeletconfig/configsync.go

@@ -0,0 +1,183 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kubeletconfig
+
+import (
+	"fmt"
+	"os"
+
+	apiv1 "k8s.io/api/core/v1"
+	clientset "k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/tools/cache"
+	"k8s.io/kubernetes/pkg/kubelet/kubeletconfig/checkpoint"
+	"k8s.io/kubernetes/pkg/kubelet/kubeletconfig/status"
+	utillog "k8s.io/kubernetes/pkg/kubelet/kubeletconfig/util/log"
+)
+
+// pokeConfiSourceWorker tells the worker thread that syncs config sources that work needs to be done
+func (cc *Controller) pokeConfigSourceWorker() {
+	select {
+	case cc.pendingConfigSource <- true:
+	default:
+	}
+}
+
+// syncConfigSource checks if work needs to be done to use a new configuration, and does that work if necessary
+func (cc *Controller) syncConfigSource(client clientset.Interface, nodeName string) {
+	select {
+	case <-cc.pendingConfigSource:
+	default:
+		// no work to be done, return
+		return
+	}
+
+	// if the sync fails, we want to retry
+	var syncerr error
+	defer func() {
+		if syncerr != nil {
+			utillog.Errorf(syncerr.Error())
+			cc.pokeConfigSourceWorker()
+		}
+	}()
+
+	node, err := latestNode(cc.informer.GetStore(), nodeName)
+	if err != nil {
+		cc.configOK.SetFailSyncCondition(status.FailSyncReasonInformer)
+		syncerr = fmt.Errorf("%s, error: %v", status.FailSyncReasonInformer, err)
+		return
+	}
+
+	// check the Node and download any new config
+	if updated, reason, err := cc.doSyncConfigSource(client, node.Spec.ConfigSource); err != nil {
+		cc.configOK.SetFailSyncCondition(reason)
+		syncerr = fmt.Errorf("%s, error: %v", reason, err)
+		return
+	} else if updated {
+		// TODO(mtaufen): Consider adding a "currently restarting kubelet" ConfigOK message for this case
+		utillog.Infof("config updated, Kubelet will restart to begin using new config")
+		os.Exit(0)
+	}
+
+	// If we get here:
+	// - there is no need to restart to update the current config
+	// - there was no error trying to sync configuration
+	// - if, previously, there was an error trying to sync configuration, we need to clear that error from the condition
+	cc.configOK.ClearFailSyncCondition()
+}
+
+// doSyncConfigSource checkpoints and sets the store's current config to the new config or resets config,
+// depending on the `source`, and returns whether the current config in the checkpoint store was updated as a result
+func (cc *Controller) doSyncConfigSource(client clientset.Interface, source *apiv1.NodeConfigSource) (bool, string, error) {
+	if source == nil {
+		utillog.Infof("Node.Spec.ConfigSource is empty, will reset current and last-known-good to defaults")
+		updated, reason, err := cc.resetConfig()
+		if err != nil {
+			return false, reason, err
+		}
+		return updated, "", nil
+	}
+
+	// if the NodeConfigSource is non-nil, download the config
+	utillog.Infof("Node.Spec.ConfigSource is non-empty, will checkpoint source and update config if necessary")
+	remote, reason, err := checkpoint.NewRemoteConfigSource(source)
+	if err != nil {
+		return false, reason, err
+	}
+	reason, err = cc.checkpointConfigSource(client, remote)
+	if err != nil {
+		return false, reason, err
+	}
+	updated, reason, err := cc.setCurrentConfig(remote)
+	if err != nil {
+		return false, reason, err
+	}
+	return updated, "", nil
+}
+
+// checkpointConfigSource downloads and checkpoints the object referred to by `source` if the checkpoint does not already exist,
+// if a failure occurs, returns a sanitized failure reason and an error
+func (cc *Controller) checkpointConfigSource(client clientset.Interface, source checkpoint.RemoteConfigSource) (string, error) {
+	uid := source.UID()
+
+	// if the checkpoint already exists, skip downloading
+	if ok, err := cc.checkpointStore.Exists(uid); err != nil {
+		reason := fmt.Sprintf(status.FailSyncReasonCheckpointExistenceFmt, uid)
+		return reason, fmt.Errorf("%s, error: %v", reason, err)
+	} else if ok {
+		utillog.Infof("checkpoint already exists for object with UID %q, skipping download", uid)
+		return "", nil
+	}
+
+	// download
+	checkpoint, reason, err := source.Download(client)
+	if err != nil {
+		return reason, fmt.Errorf("%s, error: %v", reason, err)
+	}
+
+	// save
+	err = cc.checkpointStore.Save(checkpoint)
+	if err != nil {
+		reason := fmt.Sprintf(status.FailSyncReasonSaveCheckpointFmt, checkpoint.UID())
+		return reason, fmt.Errorf("%s, error: %v", reason, err)
+	}
+
+	return "", nil
+}
+
+// setCurrentConfig updates UID of the current checkpoint in the checkpoint store to `uid` and returns whether the
+// current UID changed as a result, or a sanitized failure reason and an error.
+func (cc *Controller) setCurrentConfig(source checkpoint.RemoteConfigSource) (bool, string, error) {
+	updated, err := cc.checkpointStore.SetCurrentUpdated(source)
+	if err != nil {
+		if source == nil {
+			return false, status.FailSyncReasonSetCurrentDefault, err
+		}
+		return false, fmt.Sprintf(status.FailSyncReasonSetCurrentUIDFmt, source.UID()), err
+	}
+	return updated, "", nil
+}
+
+// resetConfig resets the current and last-known-good checkpoints in the checkpoint store to their default values and
+// returns whether the current checkpoint changed as a result, or a sanitized failure reason and an error.
+func (cc *Controller) resetConfig() (bool, string, error) {
+	updated, err := cc.checkpointStore.Reset()
+	if err != nil {
+		return false, status.FailSyncReasonReset, err
+	}
+	return updated, "", nil
+}
+
+// latestNode returns the most recent Node with `nodeName` from `store`
+func latestNode(store cache.Store, nodeName string) (*apiv1.Node, error) {
+	obj, ok, err := store.GetByKey(nodeName)
+	if err != nil {
+		err := fmt.Errorf("failed to retrieve Node %q from informer's store, error: %v", nodeName, err)
+		utillog.Errorf(err.Error())
+		return nil, err
+	} else if !ok {
+		err := fmt.Errorf("Node %q does not exist in the informer's store, can't sync config source", nodeName)
+		utillog.Errorf(err.Error())
+		return nil, err
+	}
+	node, ok := obj.(*apiv1.Node)
+	if !ok {
+		err := fmt.Errorf("failed to cast object from informer's store to Node, can't sync config source for Node %q", nodeName)
+		utillog.Errorf(err.Error())
+		return nil, err
+	}
+	return node, nil
+}