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451 lines
27 KiB
XML
451 lines
27 KiB
XML
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<?xml version="1.0" encoding="UTF-8"?>
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<!-- ============================================================================= -->
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<!-- Copyright © 2009 Red Hat, Inc. and others. -->
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<!-- -->
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<!-- The text of and illustrations in this document are licensed by Red Hat under -->
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<!-- a Creative Commons Attribution–Share Alike 3.0 Unported license ("CC-BY-SA"). -->
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<!-- -->
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<!-- An explanation of CC-BY-SA is available at -->
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<!-- -->
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<!-- http://creativecommons.org/licenses/by-sa/3.0/. -->
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<!-- -->
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<!-- In accordance with CC-BY-SA, if you distribute this document or an adaptation -->
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<!-- of it, you must provide the URL for the original version. -->
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<!-- -->
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<!-- Red Hat, as the licensor of this document, waives the right to enforce, -->
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<!-- and agrees not to assert, Section 4d of CC-BY-SA to the fullest extent -->
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<!-- permitted by applicable law. -->
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<!-- ============================================================================= -->
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<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
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<!ENTITY % BOOK_ENTITIES SYSTEM "HornetQ_User_Manual.ent">
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%BOOK_ENTITIES;
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]>
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<chapter id="jms-bridge">
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<title>The JMS Bridge</title>
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<para>HornetQ includes a fully functional JMS message bridge.</para>
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<para>The function of the bridge is to consume messages from a source queue or topic, and
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send them to a target queue or topic, typically on a different server.</para>
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<para>The source and target servers do not have to be in the same cluster which makes
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bridging suitable for reliably sending messages from one cluster to another, for
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instance across a WAN, and where the connection may be unreliable.</para>
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<para>A bridge can be deployed as a standalone application, with HornetQ standalone server or inside a JBoss AS
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instance. The source and the target can be located in the same virtual machine or another one.</para>
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<para>The bridge can also be used to bridge messages from other non HornetQ JMS servers, as
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long as they are JMS 1.1 compliant.<note><para>Do not confuse a JMS bridge with a core
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bridge. A JMS bridge can be used to bridge any two JMS 1.1 compliant JMS
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providers and uses the JMS API. A core bridge (described in <xref
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linkend="core-bridges"/>) is used to bridge any two HornetQ instances and
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uses the core API. Always use a core bridge if you can in preference to a JMS
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bridge. The core bridge will typically provide better performance than a JMS
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bridge. Also the core bridge can provide <emphasis>once and only once</emphasis>
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delivery guarantees without using XA.</para></note></para>
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<para>The bridge has built-in resilience to failure so if the source or target server
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connection is lost, e.g. due to network failure, the bridge will retry connecting to the
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source and/or target until they come back online. When it comes back online it will
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resume operation as normal.</para>
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<para>The bridge can be configured with an optional JMS selector, so it will only consume
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messages matching that JMS selector</para>
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<para>It can be configured to consume from a queue or a topic. When it consumes from a topic
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it can be configured to consume using a non durable or durable subscription</para>
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<para>Typically, the bridge is deployed by the JBoss Micro Container via a beans configuration file.
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This would typically be deployed inside the JBoss Application Server and the following
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example shows an example of a beans file that bridges 2 destinations which are actually
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on the same server. </para>
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<programlisting>
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<?xml version="1.0" encoding="UTF-8"?>
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<deployment xmlns="urn:jboss:bean-deployer:2.0">
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<bean name="JMSBridge" class="org.hornetq.api.jms.bridge.impl.JMSBridgeImpl">
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<!-- HornetQ must be started before the bridge -->
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<depends>HornetQServer</depends>
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<constructor>
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<!-- Source ConnectionFactory Factory -->
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<parameter>
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<inject bean="SourceCFF"/>
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</parameter>
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<!-- Target ConnectionFactory Factory -->
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<parameter>
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<inject bean="TargetCFF"/>
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</parameter>
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<!-- Source DestinationFactory -->
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<parameter>
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<inject bean="SourceDestinationFactory"/>
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</parameter>
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<!-- Target DestinationFactory -->
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<parameter>
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<inject bean="TargetDestinationFactory"/>
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</parameter>
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<!-- Source User Name (no username here) -->
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<parameter><null /></parameter>
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<!-- Source Password (no password here)-->
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<parameter><null /></parameter>
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<!-- Target User Name (no username here)-->
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<parameter><null /></parameter>
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<!-- Target Password (no password here)-->
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<parameter><null /></parameter>
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<!-- Selector -->
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<parameter><null /></parameter>
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<!-- Failure Retry Interval (in ms) -->
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<parameter>5000</parameter>
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<!-- Max Retries -->
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<parameter>10</parameter>
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<!-- Quality Of Service -->
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<parameter>ONCE_AND_ONLY_ONCE</parameter>
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<!-- Max Batch Size -->
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<parameter>1</parameter>
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<!-- Max Batch Time (-1 means infinite) -->
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<parameter>-1</parameter>
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<!-- Subscription name (no subscription name here)-->
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<parameter><null /></parameter>
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<!-- Client ID (no client ID here)-->
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<parameter><null /></parameter>
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<!-- Add MessageID In Header -->
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<parameter>true</parameter>
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<!-- register the JMS Bridge in the AS MBeanServer -->
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<parameter>
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<inject bean="MBeanServer"/>
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</parameter>
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<parameter>org.hornetq:service=JMSBridge</parameter>
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</constructor>
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<property name="transactionManager">
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<inject bean="RealTransactionManager"/>
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</property>
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</bean>
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<!-- SourceCFF describes the ConnectionFactory used to connect to the source destination -->
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<bean name="SourceCFF"
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class="org.hornetq.api.jms.bridge.impl.JNDIConnectionFactoryFactory">
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<constructor>
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<parameter>
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<inject bean="JNDI" />
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</parameter>
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<parameter>/ConnectionFactory</parameter>
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</constructor>
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</bean>
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<!-- TargetCFF describes the ConnectionFactory used to connect to the target destination -->
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<bean name="TargetCFF"
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class="org.hornetq.api.jms.bridge.impl.JNDIConnectionFactoryFactory">
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<constructor>
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<parameter>
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<inject bean="JNDI" />
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</parameter>
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<parameter>/ConnectionFactory</parameter>
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</constructor>
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</bean>
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<!-- SourceDestinationFactory describes the Destination used as the source -->
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<bean name="SourceDestinationFactory" class="org.hornetq.api.jms.bridge.impl.JNDIDestinationFactory">
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<constructor>
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<parameter>
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<inject bean="JNDI" />
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</parameter>
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<parameter>/queue/source</parameter>
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</constructor>
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</bean>
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<!-- TargetDestinationFactory describes the Destination used as the target -->
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<bean name="TargetDestinationFactory" class="org.hornetq.api.jms.bridge.impl.JNDIDestinationFactory">
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<constructor>
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<parameter>
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<inject bean="JNDI" />
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</parameter>
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<parameter>/queue/target</parameter>
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</constructor>
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</bean>
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<!-- JNDI is a Hashtable containing the JNDI properties required -->
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<!-- to connect to the sources and targets JMS resrouces -->
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<bean name="JNDI" class="java.util.Hashtable">
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<constructor class="java.util.Map">
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<map class="java.util.Hashtable" keyClass="String"
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valueClass="String">
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<entry>
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<key>java.naming.factory.initial</key>
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<value>org.jnp.interfaces.NamingContextFactory</value>
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</entry>
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<entry>
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<key>java.naming.provider.url</key>
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<value>jnp://localhost:1099</value>
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</entry>
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<entry>
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<key>java.naming.factory.url.pkgs</key>
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<value>org.jboss.naming:org.jnp.interfaces"</value>
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</entry>
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<entry>
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<key>jnp.timeout</key>
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<value>5000</value>
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</entry>
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<entry>
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<key>jnp.sotimeout</key>
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<value>5000</value>
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</entry>
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</map>
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</constructor>
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</bean>
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<bean name="MBeanServer" class="javax.management.MBeanServer">
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<constructor factoryClass="org.jboss.mx.util.MBeanServerLocator" factoryMethod="locateJBoss"/>
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</bean>
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</deployment></programlisting>
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<section>
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<title>JMS Bridge Parameters</title>
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<para>The main bean deployed is the <literal>JMSBridge</literal> bean. The bean is
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configurable by the parameters passed to its constructor.</para>
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<note>
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<para>To let a parameter be unspecified (for example, if the authentication is
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anonymous or no message selector is provided), use <literal><null
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/></literal> for the unspecified parameter value.</para>
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</note>
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<itemizedlist>
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<listitem>
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<para>Source Connection Factory Factory</para>
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<para>This injects the <literal>SourceCFF</literal> bean (also defined in the
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beans file). This bean is used to create the <emphasis>source</emphasis>
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<literal>ConnectionFactory</literal>
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</para>
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</listitem>
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<listitem>
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<para>Target Connection Factory Factory</para>
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<para>This injects the <literal>TargetCFF</literal> bean (also defined in the
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beans file). This bean is used to create the <emphasis>target</emphasis>
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<literal>ConnectionFactory</literal>
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</para>
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</listitem>
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<listitem>
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<para>Source Destination Factory Factory</para>
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<para>This injects the <literal>SourceDestinationFactory</literal> bean (also
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defined in the beans file). This bean is used to create the
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<emphasis>source</emphasis>
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<literal>Destination</literal>
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</para>
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</listitem>
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<listitem>
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<para>Target Destination Factory Factory</para>
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<para>This injects the <literal>TargetDestinationFactory</literal> bean (also
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defined in the beans file). This bean is used to create the
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<emphasis>target</emphasis>
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<literal>Destination</literal>
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</para>
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</listitem>
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<listitem>
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<para>Source User Name</para>
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<para>this parameter is the username for creating the
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<emphasis>source</emphasis> connection</para>
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</listitem>
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<listitem>
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<para>Source Password</para>
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<para>this parameter is the parameter for creating the
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<emphasis>source</emphasis> connection</para>
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</listitem>
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<listitem>
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<para>Target User Name</para>
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<para>this parameter is the username for creating the
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<emphasis>target</emphasis> connection</para>
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</listitem>
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<listitem>
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<para>Target Password</para>
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<para>this parameter is the password for creating the
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<emphasis>target</emphasis> connection</para>
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</listitem>
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<listitem>
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<para>Selector</para>
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<para>This represents a JMS selector expression used for consuming messages from
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the source destination. Only messages that match the selector expression
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will be bridged from the source to the target destination</para>
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<para>The selector expression must follow the <ulink
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url="http://docs.oracle.com/javaee/6/api/javax/jms/Message.html">JMS
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selector syntax</ulink></para>
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</listitem>
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<listitem>
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<para>Failure Retry Interval</para>
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<para>This represents the amount of time in ms to wait between trying to
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recreate connections to the source or target servers when the bridge has
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detected they have failed</para>
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</listitem>
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<listitem>
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<para>Max Retries</para>
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<para>This represents the number of times to attempt to recreate connections to
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the source or target servers when the bridge has detected they have failed.
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The bridge will give up after trying this number of times. <literal
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>-1</literal> represents 'try forever'</para>
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</listitem>
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<listitem>
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<para>Quality Of Service</para>
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<para>This parameter represents the desired quality of service mode</para>
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<para>Possible values are:</para>
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<itemizedlist>
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<listitem>
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<para><literal>AT_MOST_ONCE</literal></para>
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</listitem>
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<listitem>
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<para><literal>DUPLICATES_OK</literal></para>
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</listitem>
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<listitem>
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<para><literal>ONCE_AND_ONLY_ONCE</literal></para>
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</listitem>
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</itemizedlist>
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<para>See <xref linkend="quality-of-service"/> for a explanation of these
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modes.</para>
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</listitem>
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<listitem>
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<para>Max Batch Size</para>
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<para>This represents the maximum number of messages to consume from the source
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destination before sending them in a batch to the target destination. Its
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value must <literal>>= 1</literal>
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</para>
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</listitem>
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<listitem>
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<para>Max Batch Time</para>
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<para>This represents the maximum number of milliseconds to wait before sending
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a batch to target, even if the number of messages consumed has not reached
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<literal>MaxBatchSize</literal>. Its value must be <literal>-1</literal>
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to represent 'wait forever', or <literal>>= 1</literal> to specify an actual
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time </para>
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</listitem>
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<listitem>
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<para>Subscription Name</para>
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<para>If the source destination represents a topic, and you want to consume from
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the topic using a durable subscription then this parameter represents the
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durable subscription name</para>
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</listitem>
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<listitem>
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<para>Client ID</para>
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<para>If the source destination represents a topic, and you want to consume from
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the topic using a durable subscription then this attribute represents the
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the JMS client ID to use when creating/looking up the durable
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subscription</para>
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</listitem>
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<listitem>
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<para>Add MessageID In Header</para>
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<para>If <literal>true</literal>, then the original message's message ID will be
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appended in the message sent to the destination in the header <literal
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|||
|
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>HORNETQ_BRIDGE_MSG_ID_LIST</literal>. If the message is bridged more
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than once, each message ID will be appended. This enables a distributed
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|||
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request-response pattern to be used</para>
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|||
|
|
<note>
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|||
|
|
<para>when you receive the message you can send back a response using the
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|||
|
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correlation id of the first message id, so when the original sender gets
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|||
|
|
it back it will be able to correlate it. </para>
|
|||
|
|
</note>
|
|||
|
|
</listitem>
|
|||
|
|
<listitem>
|
|||
|
|
<para>MBean Server</para>
|
|||
|
|
<para>To manage the JMS Bridge using JMX, set the MBeanServer where the JMS Bridge MBean
|
|||
|
|
must be registered (e.g. the JVM Platform MBeanServer or JBoss AS MBeanServer)</para>
|
|||
|
|
</listitem>
|
|||
|
|
<listitem>
|
|||
|
|
<para>ObjectName</para>
|
|||
|
|
<para>If you set the MBeanServer, you also need to set the ObjectName used to register
|
|||
|
|
the JMS Bridge MBean (must be unique)</para>
|
|||
|
|
</listitem>
|
|||
|
|
</itemizedlist>
|
|||
|
|
<para>The "transactionManager" property points to a JTA transaction manager implementation.
|
|||
|
|
HornetQ doesn't ship with such an implementation, but one is available in the JBoss
|
|||
|
|
Community. If you are running HornetQ in standalone mode and wish to use a JMS bridge
|
|||
|
|
simply download the latest version of JBossTS from http://www.jboss.org/jbosstm/downloads
|
|||
|
|
and add it to HornetQ's classpath. If you are running HornetQ with JBoss AS then you
|
|||
|
|
won't need to do this as JBoss AS ships with a JTA transaction manager already. The
|
|||
|
|
bean definition for the transaction manager would look something like this:
|
|||
|
|
</para>
|
|||
|
|
<programlisting><bean name="RealTransactionManager" class="com.arjuna.ats.internal.jta.transaction.arjunacore.TransactionManagerImple"/></programlisting>
|
|||
|
|
</section>
|
|||
|
|
<section>
|
|||
|
|
<title>Source and Target Connection Factories</title>
|
|||
|
|
<para>The source and target connection factory factories are used to create the
|
|||
|
|
connection factory used to create the connection for the source or target
|
|||
|
|
server.</para>
|
|||
|
|
<para>The configuration example above uses the default implementation provided by
|
|||
|
|
HornetQ that looks up the connection factory using JNDI. For other Application
|
|||
|
|
Servers or JMS providers a new implementation may have to be provided. This can
|
|||
|
|
easily be done by implementing the interface <literal
|
|||
|
|
>org.hornetq.jms.bridge.ConnectionFactoryFactory</literal>.</para>
|
|||
|
|
</section>
|
|||
|
|
<section>
|
|||
|
|
<title>Source and Target Destination Factories</title>
|
|||
|
|
<para>Again, similarly, these are used to create or lookup up the destinations.</para>
|
|||
|
|
<para>In the configuration example above, we have used the default provided by HornetQ
|
|||
|
|
that looks up the destination using JNDI.</para>
|
|||
|
|
<para>A new implementation can be provided by implementing <literal
|
|||
|
|
>org.hornetq.jms.bridge.DestinationFactory</literal> interface.</para>
|
|||
|
|
</section>
|
|||
|
|
<section id="quality-of-service">
|
|||
|
|
<title>Quality Of Service</title>
|
|||
|
|
<para>The quality of service modes used by the bridge are described here in more
|
|||
|
|
detail.</para>
|
|||
|
|
<section>
|
|||
|
|
<title>AT_MOST_ONCE</title>
|
|||
|
|
<para>With this QoS mode messages will reach the destination from the source at most
|
|||
|
|
once. The messages are consumed from the source and acknowledged before sending
|
|||
|
|
to the destination. Therefore there is a possibility that if failure occurs
|
|||
|
|
between removing them from the source and them arriving at the destination they
|
|||
|
|
could be lost. Hence delivery will occur at most once.</para>
|
|||
|
|
<para>This mode is available for both durable and non-durable messages.</para>
|
|||
|
|
</section>
|
|||
|
|
<section>
|
|||
|
|
<title>DUPLICATES_OK</title>
|
|||
|
|
<para>With this QoS mode, the messages are consumed from the source and then
|
|||
|
|
acknowledged after they have been successfully sent to the destination.
|
|||
|
|
Therefore there is a possibility that if failure occurs after sending to the
|
|||
|
|
destination but before acknowledging them, they could be sent again when the
|
|||
|
|
system recovers. I.e. the destination might receive duplicates after a
|
|||
|
|
failure.</para>
|
|||
|
|
<para>This mode is available for both durable and non-durable messages.</para>
|
|||
|
|
</section>
|
|||
|
|
<section>
|
|||
|
|
<title>ONCE_AND_ONLY_ONCE</title>
|
|||
|
|
<para>This QoS mode ensures messages will reach the destination from the source once
|
|||
|
|
and only once. (Sometimes this mode is known as "exactly once"). If both the
|
|||
|
|
source and the destination are on the same HornetQ server instance then this can
|
|||
|
|
be achieved by sending and acknowledging the messages in the same local
|
|||
|
|
transaction. If the source and destination are on different servers this is
|
|||
|
|
achieved by enlisting the sending and consuming sessions in a JTA transaction.
|
|||
|
|
The JTA transaction is controlled by JBoss Transactions JTA * implementation
|
|||
|
|
which is a fully recovering transaction manager, thus providing a very high
|
|||
|
|
degree of durability. If JTA is required then both supplied connection factories
|
|||
|
|
need to be XAConnectionFactory implementations. This is likely to be the slowest
|
|||
|
|
mode since it requires extra persistence for the transaction logging.</para>
|
|||
|
|
<para>This mode is only available for durable messages.</para>
|
|||
|
|
<note>
|
|||
|
|
<para>For a specific application it may possible to provide once and only once
|
|||
|
|
semantics without using the ONCE_AND_ONLY_ONCE QoS level. This can be done
|
|||
|
|
by using the DUPLICATES_OK mode and then checking for duplicates at the
|
|||
|
|
destination and discarding them. Some JMS servers provide automatic
|
|||
|
|
duplicate message detection functionality, or this may be possible to
|
|||
|
|
implement on the application level by maintaining a cache of received
|
|||
|
|
message ids on disk and comparing received messages to them. The cache would
|
|||
|
|
only be valid for a certain period of time so this approach is not as
|
|||
|
|
watertight as using ONCE_AND_ONLY_ONCE but may be a good choice depending on
|
|||
|
|
your specific application.</para>
|
|||
|
|
</note>
|
|||
|
|
</section>
|
|||
|
|
<section>
|
|||
|
|
<title>Time outs and the JMS bridge</title>
|
|||
|
|
<para>There is a possibility that the target or source server will not be available at some point in time.
|
|||
|
|
If this occurs then the bridge will try <literal>Max Retries</literal> to reconnect every
|
|||
|
|
<literal>Failure Retry Interval</literal> milliseconds as specified in the JMS Bridge definition.</para>
|
|||
|
|
<para>However since a third party JNDI is used, in this case the JBoss naming server, it is possible for the
|
|||
|
|
JNDI lookup to hang if the network were to disappear during the JNDI lookup. To stop this from occurring the JNDI
|
|||
|
|
definition can be configured to time out if this occurs. To do this set the <literal>jnp.timeout</literal>
|
|||
|
|
and the <literal>jnp.sotimeout</literal> on the Initial Context definition. The first sets the connection
|
|||
|
|
timeout for the initial connection and the second the read timeout for the socket.</para>
|
|||
|
|
<note>
|
|||
|
|
<para>Once the initial JNDI connection has succeeded all calls are made using RMI. If you want to control
|
|||
|
|
the timeouts for the RMI connections then this can be done via system properties. JBoss uses Sun's RMI
|
|||
|
|
and the properties can be found <ulink
|
|||
|
|
url="http://docs.oracle.com/javase/6/docs/technotes/guides/rmi/sunrmiproperties.html">here</ulink>.
|
|||
|
|
The default connection timeout is 10 seconds and the default read timeout is 18 seconds.</para>
|
|||
|
|
</note>
|
|||
|
|
<para>If you implement your own factories for looking up JMS resources then you will have to bear in mind timeout issues.</para>
|
|||
|
|
</section>
|
|||
|
|
<section>
|
|||
|
|
<title>Examples</title>
|
|||
|
|
<para>Please see <xref linkend="examples.javaee.jms-bridge"/> which shows how to configure
|
|||
|
|
and use a JMS Bridge with JBoss AS to send messages to the source destination and consume them
|
|||
|
|
from the target destination.</para>
|
|||
|
|
<para>Please see <xref linkend="examples.jms.jms-bridge"/> which shows how to configure
|
|||
|
|
and use a JMS Bridge between two standalone HornetQ servers.</para>
|
|||
|
|
</section>
|
|||
|
|
</section>
|
|||
|
|
</chapter>
|