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Merge pull request #47 from divyenpatel/cns-csi-driver-common-code
Common library for CNS CSI driver
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,190 @@ | ||
| /* | ||
| Copyright 2019 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 node | ||
|
|
||
| import ( | ||
| "errors" | ||
| "strings" | ||
| "sync" | ||
|
|
||
| "k8s.io/klog" | ||
| ) | ||
|
|
||
| // ErrNodeAlreadyExists is returned if there's exists a node with | ||
| // the same name but different UUID. | ||
| var ErrNodeAlreadyExists = errors.New("another node with the same name exists") | ||
|
|
||
| // Cache provides thread-safe functionality to cache node information. Note that | ||
| // node names are handled in a case sensitive manner, and must be unique. | ||
| type Cache interface { | ||
| // DeleteNodeByUUID deletes a node entry by its UUID and returns its current name. | ||
| DeleteNodeByUUID(nodeUUID string) (string, error) | ||
| // DeleteNodeByName deletes a node entry by its name and returns its current UUID. | ||
| DeleteNodeByName(nodeName string) (string, error) | ||
| // LoadNodeNameByUUID returns a node's name given its UUID. | ||
| LoadNodeNameByUUID(nodeUUID string) (string, error) | ||
| // LoadNodeUUIDByName returns a node's UUID given its name. | ||
| LoadNodeUUIDByName(nodeName string) (string, error) | ||
| // Range calls f sequentially for each node entry. | ||
| Range(f func(nodeUUID, nodeName string) bool) | ||
| // Store associates the node UUID with its name. If the node UUID already | ||
| // exists in the Cache, the name associated with it is updated. | ||
| Store(nodeUUID, nodeName string) error | ||
| } | ||
|
|
||
| var ( | ||
| // cacheInstance is a Cache singleton. | ||
| cacheInstance *defaultCache | ||
| // onceForCache is used for initializing the Cache singleton. | ||
| onceForCache sync.Once | ||
| ) | ||
|
|
||
| // GetCache returns the Cache singleton. | ||
| func GetCache() Cache { | ||
| onceForCache.Do(func() { | ||
| klog.V(1).Info("Initializing node.defaultCache") | ||
| cacheInstance = &defaultCache{ | ||
| uuidsToNames: make(map[string]string), | ||
| namesToUUIDs: make(map[string]string), | ||
| } | ||
| klog.V(1).Info("node.defaultCache initialized") | ||
| }) | ||
| return cacheInstance | ||
| } | ||
|
|
||
| // defaultCache caches node information and provides functionality around it. | ||
| type defaultCache struct { | ||
| // mutex is used to ensure atomicity. | ||
| sync.Mutex | ||
| // uuidsToNames map node UUIDs to their names. | ||
| uuidsToNames map[string]string | ||
| // namesToUUIDs map node names to their UUIDs. | ||
| namesToUUIDs map[string]string | ||
| } | ||
|
|
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| func normalizeUUID(nodeUUID string) string { | ||
| return strings.ToLower(nodeUUID) | ||
| } | ||
|
|
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| func (c *defaultCache) DeleteNodeByUUID(nodeUUID string) (string, error) { | ||
| c.Lock() | ||
| defer c.Unlock() | ||
|
|
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| nodeUUID = normalizeUUID(nodeUUID) | ||
| nodeName, exists := c.uuidsToNames[nodeUUID] | ||
| if !exists { | ||
| klog.Warningf("Node entry wasn't found with nodeUUID %s", nodeUUID) | ||
| return "", ErrNodeNotFound | ||
| } | ||
|
|
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| delete(c.uuidsToNames, nodeUUID) | ||
| delete(c.namesToUUIDs, nodeName) | ||
| klog.V(2).Infof("Node entry was deleted with nodeUUID %s and nodeName %s", nodeUUID, nodeName) | ||
|
|
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| return nodeName, nil | ||
| } | ||
|
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| func (c *defaultCache) DeleteNodeByName(nodeName string) (string, error) { | ||
| c.Lock() | ||
| defer c.Unlock() | ||
|
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| nodeUUID, exists := c.namesToUUIDs[nodeName] | ||
| if !exists { | ||
| klog.Warningf("Node entry wasn't found with nodeName %s", nodeName) | ||
| return "", ErrNodeNotFound | ||
| } | ||
|
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| delete(c.namesToUUIDs, nodeName) | ||
| delete(c.uuidsToNames, nodeUUID) | ||
| klog.V(2).Infof("Node entry was deleted with nodeUUID %s and nodeName %s", nodeUUID, nodeName) | ||
| return nodeUUID, nil | ||
| } | ||
|
|
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| func (c *defaultCache) LoadNodeNameByUUID(nodeUUID string) (string, error) { | ||
| nodeUUID = normalizeUUID(nodeUUID) | ||
| c.Lock() | ||
| nodeName, exists := c.uuidsToNames[nodeUUID] | ||
| c.Unlock() | ||
|
|
||
| if !exists { | ||
| klog.Warningf("Node entry wasn't found with nodeUUID %s", nodeUUID) | ||
| return "", ErrNodeNotFound | ||
| } | ||
| klog.V(2).Infof("Node entry was loaded with nodeUUID %s and nodeName %s", nodeUUID, nodeName) | ||
| return nodeName, nil | ||
| } | ||
|
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| func (c *defaultCache) LoadNodeUUIDByName(nodeName string) (string, error) { | ||
| c.Lock() | ||
| nodeUUID, exists := c.namesToUUIDs[nodeName] | ||
| c.Unlock() | ||
|
|
||
| if !exists { | ||
| klog.Warningf("Node entry wasn't found with nodeName %s", nodeName) | ||
| return "", ErrNodeNotFound | ||
| } | ||
|
|
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| klog.V(2).Infof("Node entry was loaded with nodeUUID %s and nodeName %s", nodeUUID, nodeName) | ||
| return nodeUUID, nil | ||
| } | ||
|
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| func (c *defaultCache) Range(findNodeEntry func(string, string) bool) { | ||
| c.Lock() | ||
| defer c.Unlock() | ||
|
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| for nodeUUID, nodeName := range c.uuidsToNames { | ||
| klog.V(4).Infof("Calling findNodeEntry func for node entry with nodeUUID %s and nodeName %s", | ||
| nodeUUID, nodeName) | ||
|
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| if !findNodeEntry(nodeUUID, nodeName) { | ||
| klog.V(4).Infof("findNodeEntry func returned false for node entry with nodeUUID %s and nodeName %s, "+ | ||
| "breaking", nodeUUID, nodeName) | ||
| break | ||
| } | ||
| } | ||
| } | ||
|
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| func (c *defaultCache) Store(nodeUUID, nodeName string) error { | ||
| c.Lock() | ||
| defer c.Unlock() | ||
|
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| // Return an error if there exists a node with the same name but different UUID. | ||
| nodeUUID = normalizeUUID(nodeUUID) | ||
| prevNameForUUID, prevNameExistsForUUID := c.uuidsToNames[nodeUUID] | ||
| prevUUIDForName, prevUUIDExistsForName := c.namesToUUIDs[nodeName] | ||
| if prevNameExistsForUUID && prevUUIDExistsForName && prevUUIDForName != nodeUUID { | ||
| klog.Errorf("Another node with the same name %s exists with nodeUUID %s and prevUUIDForName %s", | ||
| nodeName, nodeUUID, prevUUIDForName) | ||
| return ErrNodeAlreadyExists | ||
| } | ||
|
|
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| // Clear cache entry for the given UUID and name, along with previously associated values. | ||
| delete(c.uuidsToNames, nodeUUID) | ||
| delete(c.namesToUUIDs, nodeName) | ||
| if prevNameExistsForUUID { | ||
| delete(c.namesToUUIDs, prevNameForUUID) | ||
| } | ||
| if prevUUIDExistsForName { | ||
| delete(c.uuidsToNames, prevUUIDForName) | ||
| } | ||
|
|
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| // Store the new node UUID and name. | ||
| c.uuidsToNames[nodeUUID] = nodeName | ||
| c.namesToUUIDs[nodeName] = nodeUUID | ||
| klog.V(2).Infof("Node entry was stored with nodeUUID %s and nodeName %s", nodeUUID, nodeName) | ||
| return nil | ||
| } |
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