作者简介：鸿哥，硕士研究生，国内某通信设备公司软件研发工程师，主要从事云计算、SDN技术开发
前言
在上一篇文章《ODL中拓扑展现功能总结》中提到inventory-manager模块，现在来分析下inventory-manager模块。inventory-manager模块也是作为openflowplugin的应用层程序，位于openflowplugin-release-lithium-sr3文件夹的applications当中，负责处理operational数据库下的opendaylight-inventory数据节点（datastore数据库）的增删改查，比如odl控制器新加一台openflow交换机或者移除一台交换机。同时opendaylight-inventory数据节点还为前端提供数据支撑，首先来看yang模型。
1 YANG数据模型
ODL在controller\opendaylight\md-sal\model\model-inventory\src\main\yang\opendaylight-inventory.yang文件当中定义了inventory的数据节点的树形结构：
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container nodes { description "The root container of all nodes."; list node { key "id"; ext:context-instance "node-context"; description "A list of nodes (as defined by the 'grouping node')."; uses node; //this refers to the 'grouping node' defined above. } } grouping node { description "Describes the contents of a generic node - essentially an ID and a list of node-connectors. Acts as an augmentation point where other yang files can add additional information."; leaf id { type node-id; description "The unique identifier for the node."; } list "node-connector" { key "id"; description "A list of node connectors that belong this node."; ext:context-instance "node-connector-context"; uses node-connector; } } grouping node-connector { description "Describes a generic node connector which consists of an ID. Acts as an augmentation point where other yang files can add additional information."; leaf id { type node-connector-id; description "The unique identifier for the node-connector."; } } |
并且在yang语法当中还可以使用Augmentation来在某个节点下插入其他数据。同时还定义了以下notification通告：
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node-updated //交换机节点添加消息 node-removed //交换机节点删除消息 node-connector-updated //交换机端口up消息 node-connector-removed //交换机端口down消息 |
这样在openflowplugin基础模块中发通告，在inventory-manager中接收通告并处理交换机节点信息。
2 相关依赖
ODL控制器与openflow交换机通过openflow协议建立连接（注意此时的链接已经实现TLS加密，所以可以在配置文件当中启用）之后，openflowplugin会通过notification的形式发布通告，具体在org.opendaylight.openflowplugin.openflow.md.core.sal包下的SalRegistrationManager.java文件当中的以下两个函数。
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public void onSessionAdded(final SwitchSessionKeyOF sessionKey, final SessionContext context) //与交换机建立连接 public void onSessionRemoved(final SessionContext context) //与交换机失去连接 |
例如进入onSessionAdded函数，将会发出NodeUpdated的notification，而inventory-manager管理模块因为事先注册接收该通告，所以能够收到该通告并进入inventory-manager的处理逻辑。
3 代码流程
inventory-manager的入口在InventoryManagerImplModule.java文件的createInstance（）函数，进入该函数后new出NodeChangeCommiter对象，并注册OpendaylightInventoryListener通告的接收器，因此NodeChangeCommiter对象专门处理以下几类通告：
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onNodeUpdated //交换机节点上线事件 onNodeRemoved //交换机节点下线事件 onNodeConnectorRemoved //交换机端口down事件 onNodeConnectorUpdated //交换机端口up事件 |
3.1 onNodeUpdated事件
当ODL控制器与openflow交换机建立连接之后，就会触发onNodeUpdated函数，此时Inventory-manager模块做的事情就是将该节点写入yang的node节点（datastore数据库）。
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public synchronized void onNodeUpdated(final NodeUpdated node) { //判断该节点是否是需要delete的节点 if (deletedNodeCache.getIfPresent(node.getNodeRef()) != null){ deletedNodeCache.invalidate(node.getNodeRef()); } //获取需要写入的数据树节点位置 final FlowCapableNodeUpdated flowNode = node.getAugmentation(FlowCapableNodeUpdated.class); if (flowNode == null) { return; } LOG.debug("Node updated notification received,{}", node.getNodeRef().getValue()); manager.enqueue(new InventoryOperation() { @Override public void applyOperation(ReadWriteTransaction tx) { final NodeRef ref = node.getNodeRef(); @SuppressWarnings("unchecked") //组装node数据 InstanceIdentifierBuilder<Node> builder = ((InstanceIdentifier<Node>) ref.getValue()).builder(); InstanceIdentifierBuilder<FlowCapableNode> augmentation = builder.augmentation(FlowCapableNode.class); final InstanceIdentifier<FlowCapableNode> path = augmentation.build(); CheckedFuture<Optional<FlowCapableNode>, ?> readFuture = tx.read(LogicalDatastoreType.OPERATIONAL, path); Futures.addCallback(readFuture, new FutureCallback<Optional<FlowCapableNode>>() { @Override public void onSuccess(Optional<FlowCapableNode> optional) { enqueueWriteNodeDataTx(node, flowNode, path); if (!optional.isPresent()) { enqueuePutTable0Tx(ref); } } @Override public void onFailure(Throwable throwable) { LOG.debug(String.format("Can't retrieve node data for node %s. Writing node data with table0.", node)); enqueueWriteNodeDataTx(node, flowNode, path); enqueuePutTable0Tx(ref); } }); } }); } |
3.2 onNodeRemoved事件
ODL控制器与openflow交换机断开连接之后，就会触发onNodeRemoved函数，此时Inventory-manager模块需要将该节点从数据库datastore删除该node节点。
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public synchronized void onNodeRemoved(final NodeRemoved node) { if(deletedNodeCache.getIfPresent(node.getNodeRef()) == null){ deletedNodeCache.put(node.getNodeRef(), Boolean.TRUE); } else { //its been noted that creating an operation for already removed node, fails // the entire transaction chain, there by failing deserving removals LOG.debug("Already received notification to remove node, {} - Ignored", node.getNodeRef().getValue()); return; } LOG.debug("Node removed notification received, {}", node.getNodeRef().getValue()); //删除节点 manager.enqueue(new InventoryOperation() { @Override public void applyOperation(final ReadWriteTransaction tx) { final NodeRef ref = node.getNodeRef(); LOG.debug("removing node : {}", ref.getValue()); tx.delete(LogicalDatastoreType.OPERATIONAL, ref.getValue()); } }); } |
3.3 onNodeConnectorRemoved事件
当openflow交换机端口变成down之后，就会触发onNodeConnectorRemoved函数，此时Inventory-manager模块需要将该节点从数据库datastore删除该NodeConnector节点。
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public synchronized void onNodeConnectorRemoved(final NodeConnectorRemoved connector) { if(deletedNodeConnectorCache.getIfPresent(connector.getNodeConnectorRef()) == null){ deletedNodeConnectorCache.put(connector.getNodeConnectorRef(), Boolean.TRUE); } else { //its been noted that creating an operation for already removed node-connectors, fails // the entire transaction chain, there by failing deserving removals LOG.debug("Already received notification to remove nodeConnector, {} - Ignored", connector.getNodeConnectorRef().getValue()); return; } LOG.debug("Node connector removed notification received, {}", connector.getNodeConnectorRef().getValue()); manager.enqueue(new InventoryOperation() { @Override public void applyOperation(final ReadWriteTransaction tx) { final NodeConnectorRef ref = connector.getNodeConnectorRef(); LOG.debug("removing node connector {} ", ref.getValue()); tx.delete(LogicalDatastoreType.OPERATIONAL, ref.getValue()); } }); } |
3.4 onNodeConnectorUpdated事件
当openflow交换机端口变成up之后，就会触发onNodeConnectorUpdated函数，此时Inventory-manager模块需要添加该NodeConnector节点到数据库datastore。
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public synchronized void onNodeConnectorUpdated(final NodeConnectorUpdated connector) { if (deletedNodeConnectorCache.getIfPresent(connector.getNodeConnectorRef()) != null){ deletedNodeConnectorCache.invalidate(connector.getNodeConnectorRef()); } LOG.debug("Node connector updated notification received."); manager.enqueue(new InventoryOperation() { @Override public void applyOperation(final ReadWriteTransaction tx) { final NodeConnectorRef ref = connector.getNodeConnectorRef(); final NodeConnectorBuilder data = new NodeConnectorBuilder(connector); data.setKey(new NodeConnectorKey(connector.getId())); final FlowCapableNodeConnectorUpdated flowConnector = connector .getAugmentation(FlowCapableNodeConnectorUpdated.class); if (flowConnector != null) { final FlowCapableNodeConnector augment = InventoryMapping.toInventoryAugment(flowConnector); data.addAugmentation(FlowCapableNodeConnector.class, augment); } InstanceIdentifier<NodeConnector> value = (InstanceIdentifier<NodeConnector>) ref.getValue(); LOG.debug("updating node connector : {}.", value); NodeConnector build = data.build(); tx.merge(LogicalDatastoreType.OPERATIONAL, value, build, true); } }); |
4 总结
inventory-manager同样作为ODL的APP形式管理inventory节点信息，位于Openflowplguin的applications文件夹，而Openflowplguin模块当中的applications是建立在Openflowplguin基础模块之上的，比如openflowplugin-impl、openflowplugin等，由Openflowplguin基础模块处理好openflow协议最后发出node新加、更新、删除等通告。
一旦inventory-manager模块更新datastore数据树，topology-manager模块会监听此变化，并且更新自己的数据树，需要注意的是在web上显示的拓扑图都是拿topology-manager模块的数据树而非拿inventory-manager数据树进行展现。
