【ZStack】5.通用插件系统

public static L2NetworkType type = new L2NetworkType("Openvswitch");

/* once the type is declared as above, there will be a new L2 network type called 'Openvswitch' that can be retrieved by API */（一旦类型被声明，一个新的叫做“Openvswitch”的l2网络类型可以被API检索）

public class OpenvswitchL2NetworkFactory implements L2NetworkFactory {
    @Override
    public L2NetworkType getType() {
        /* return type defined in 1.1 */
        return type;
    }

    @Override
    public L2NetworkInventory createL2Network(L2NetworkVO vo, APICreateL2NetworkMsg msg) {
        /*
         * new resource will normally have own creational API APICreateOpenvswitchL2NetworkMsg that
         * usually inherits APICreateL2NetworkMsg, and own database object OpenvswitchL2NetworkVO that
         * usually inherits L2NetworkVO, and a java bean OpenvswitchL2NetworkInventory that usually inherits
         * L2NetworkInventory representing all properties of Openvswitch L2 network.
         */（新的资源将通常有一个创建的API APICreateOpenvswitchL2NetworkMsg，通常继承自APICreateL2NetworkMsg，还将有自己的数据库对象，OpenvswitchL2NetworkVO，通常继承自L2NetworkVO，和一个java bean OpenvswitchL2NetworkInventory，通常在L2NetworkInventory中表示Openvswitch L2网络的所有属性）

         APICreateOpenvswitchL2NetworkMsg cmsg = (APICreateOpenvswitchL2NetworkMsg)APICreateL2NetworkMsg;
         OpenvswitchL2NetworkVO cvo = new OpenvswitchL2NetworkVO(vo);
         evaluate_OpenvswitchL2NetworkVO_with_parameters_in_API(cvo, cmsg);
         save_to_database(cvo);
         return OpenvswitchL2NetworkInventory.valueOf(cvo);
    }

    @Override
    public L2Network getL2Network(L2NetworkVO vo) {
        /* return the concrete implementation defined in 1.3 */
        return new OpenvswitchL2Network(vo);
    }
}

public class OpenvswitchL2Network extends L2NoVlanNetwork {
    public OpenvswitchL2Network(L2NetworkVO self) {
        super(self);
    }

    @Override
    public void handleMessage(Message msg) {
        /* handle Openvswitch L2 network specific messages(both API and non API) and delegate
         * others to the base class L2NoVlanNetwork; so the implementation can focus on own business
         * logic and let the base class handle things like attaching cluster, detaching cluster;
         * of course, the implementation can override any message handler if it wants, for example,
         * override L2NetworkDeletionMsg to do some cleanup work before being deleted.
（处理和Openvswitch L2网络相关的特定消息（API消息或不是API的消息），并把其他消息交给L2NoVlanNetwork的基础类处理；所以它的实现可以关注它自身的业务逻辑，并让基础类处理一些如绑定集群，解绑集群，的事情。当然，实现方法也可以覆盖任何消息处理器，例如，覆盖L2NetworkDeletionMsg在删除前做一些清理工作。）
         */
        if (msg instanceof OpenvswitchL2NetworkSpecificMsg1) {
            handle((OpenvswitchL2NetworkSpecificMsg1)msg);
        } else if (msg instanceof OpenvswitchL2NetworkSpecificMsg2) {
            handle((OpenvswitchL2NetworkSpecificMsg2)msg);
        } else {
            super.handleMessage(msg);
        }
    }
}

PreVmInstantiateResourceExtensionPoint:
public class OpenvswitchL2NetworkCreateGRETunnel implements PreVmInstantiateResourceExtensionPoint {
    @Override
    public void preBeforeInstantiateVmResource(VmInstanceSpec spec) throws VmInstantiateResourceException {
       /*
       * you can do some check here; if any condition makes you think the VM should not be created/started,
       * you can throw VmInstantiateResourceException to stop it
       */
    }

    @Override
    public void preInstantiateVmResource(VmInstanceSpec spec, Completion completion) {
        /* create the GRE tunnel, you can get all necessary information about the VM from VmInstanceSpec */
        completion.success();
    }

    @Override
    public void preReleaseVmResource(VmInstanceSpec spec, Completion completion) {
       /*
       *in case VM fails to create/start for some reason, for cleanup, you can delete the prior created GRE tunnel here
       */
        completion.success();
    }
}

public class OpenvswitchL2NetworkKVMHostConnectedExtension implements KVMHostConnectExtensionPoint {
    @Override
    public void kvmHostConnected(KVMHostConnectedContext context) throws KVMHostConnectException {
        /*
         * you can use various methods like SSH login, HTTP call to KVM agent to check the Openvswitch daemon你可以使用很多方式（如SSH登录，KVM代理的HTTP调用）通过使用在KVMHostConnectedContext上的信息，去检查在主机上的Openvswitch的守护进程。如果任意状态让你认为主机不能提供Openvswitch L2网络方法，你可以抛出KVMHostConnectExtensionPoint去阻止主机连接。
         * on the host, using information in KVMHostConnectedContext. If any condition makes you think the
         * host cannot provide Openvswitch L2 network function, you can throw KVMHostConnectExtensionPoint to
         * stop the host from being connected.
         */
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx" xmlns:zstack="http://zstack.org/schema/zstack"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
    http://www.springframework.org/schema/aop
    http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
    http://www.springframework.org/schema/tx
    http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
    http://zstack.org/schema/zstack
    http://zstack.org/schema/zstack/plugin.xsd"
    default-init-method="init" default-destroy-method="destroy">

    <bean id="OpenvswitchL2NetworkCreateGRETunnel" class="org.zstack.network.l2.ovs.OpenvswitchL2NetworkCreateGRETunnel">
        <zstack:plugin>
            <zstack:extension interface="org.zstack.header.vm.PreVmInstantiateResourceExtensionPoint" />
        </zstack:plugin>
    </bean>

    <bean id="OpenvswitchL2NetworkKVMHostConnectedExtension"
          class="org.zstack.network.l2.ovs.OpenvswitchL2NetworkKVMHostConnectedExtension">
        <zstack:plugin>
            <zstack:extension interface="org.zstack.kvm.KVMHostConnectExtensionPoint" />
        </zstack:plugin>
    </bean>

</beans>