Author: rajika Date: Sat Jun 27 00:41:31 2009 New Revision: 40122 URL: http://wso2.org/svn/browse/wso2?view=rev&revision=40122
Log: Added endpoint guide. Added: trunk/esb/java/docs/resources/images/endpoint-info.png (contents, props changed) trunk/esb/java/docs/resources/images/endpoint-mbean.png (contents, props changed) trunk/esb/java/docs/resources/images/endpoint-off.png (contents, props changed) trunk/esb/java/docs/resources/images/endpoint-state.png (contents, props changed) trunk/esb/java/docs/resources/images/endpoint-turn-off.png (contents, props changed) trunk/esb/java/docs/resources/images/jconsole-mbean.png (contents, props changed) trunk/esb/java/docs/xdoc/endpoint_guide.xml Added: trunk/esb/java/docs/resources/images/endpoint-info.png URL: http://wso2.org/svn/browse/wso2/trunk/esb/java/docs/resources/images/endpoint-info.png?pathrev=40122 ============================================================================== Binary file. No diff available. Added: trunk/esb/java/docs/resources/images/endpoint-mbean.png URL: http://wso2.org/svn/browse/wso2/trunk/esb/java/docs/resources/images/endpoint-mbean.png?pathrev=40122 ============================================================================== Binary file. No diff available. Added: trunk/esb/java/docs/resources/images/endpoint-off.png URL: http://wso2.org/svn/browse/wso2/trunk/esb/java/docs/resources/images/endpoint-off.png?pathrev=40122 ============================================================================== Binary file. No diff available. Added: trunk/esb/java/docs/resources/images/endpoint-state.png URL: http://wso2.org/svn/browse/wso2/trunk/esb/java/docs/resources/images/endpoint-state.png?pathrev=40122 ============================================================================== Binary file. No diff available. Added: trunk/esb/java/docs/resources/images/endpoint-turn-off.png URL: http://wso2.org/svn/browse/wso2/trunk/esb/java/docs/resources/images/endpoint-turn-off.png?pathrev=40122 ============================================================================== Binary file. No diff available. Added: trunk/esb/java/docs/resources/images/jconsole-mbean.png URL: http://wso2.org/svn/browse/wso2/trunk/esb/java/docs/resources/images/jconsole-mbean.png?pathrev=40122 ============================================================================== Binary file. No diff available. Added: trunk/esb/java/docs/xdoc/endpoint_guide.xml URL: http://wso2.org/svn/browse/wso2/trunk/esb/java/docs/xdoc/endpoint_guide.xml?pathrev=40122 ============================================================================== --- (empty file) +++ trunk/esb/java/docs/xdoc/endpoint_guide.xml Sat Jun 27 00:41:31 2009 @@ -0,0 +1,506 @@ +<?xml version="1.0" encoding="iso-8859-1"?> +<!-- + ~ Copyright (c) 2005-2008, WSO2 Inc. (http://www.wso2.org) All Rights Reserved. + ~ + ~ WSO2 Inc. licenses this file to you 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. + ~ + --> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" + "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd";> +<html xmlns="http://www.w3.org/1999/xhtml";> +<head> + <meta http-equiv="content-type" content="text/html; charset=iso-8859-1" /> + <title>WSO2 ESB - Endpoint Guide </title> + <link href="css/esb-docs.css" rel="stylesheet" /> + <link href="styles/dist-docs.css" rel="stylesheet" type="text/css" + media="all" /> +</head> + + +<body xml:lang="en"> +<h2>Endpoint Guide</h2> +<h3>Endpoints</h3> +<p>An endpoint +defines an external destination for an outgoing message through WSO2 +ESB. An <endpoint> element defines an endpoint in the +configuration. An endpoint may be specified as an address endpoint, WSDL based endpoint, a load +balancing endpoint or a fail-over endpoint as follows: +</p> + +<pre xml:space="preserve"> + <endpoint [name="string"] [key="string"]> + address-endpoint | default-endpoint | wsdl-endpoint | load-balanced-endpoint | fail-over-endpoint + </endpoint> +</pre> +<p> +All the types of endpoints can have a name attribute which specify the name of the endpoint and such named endpoints + can be referred by other endpoints using a key attribute. For example if there is an endpoint named as "foo", +the following endpoint can be used in any place, where "foo" has to be used. +</p> + +<pre xml:space="preserve"> + <endpoint key="foo"/> +</pre> +<p>This let the users to reuse the already defined endpoints in several places.</p> +<p>The endpoints also have a trace attribute which turns on detailed trace information for messages being sent to the + endpoint. These are available in the trace.log configured via the log4j.properties file(which can be found within + lib folder once you unzip wso2 ESB zip). Setting the trace log level to TRACE will dump detailed trace information + including message payloads. +</p> +<p> +At any given time an endpoint can be one of the following four states.</p> + +<p><b>[1] Active</b> - Endpoint is active and running.</p> +<p><b>[2] TimeOut </b>- The endpoint can be in TimeOut state if + we get a timeout error when invoking the endpoint (because the endpoint is currently unavailable or due to a + network failure) or if it returns a previously defined error code for timeout state, the endpoint said to be in + TimeOut state. The possible error codes can be found in the <a title="SynapseConstant class" target="_blank" + href="https://svn.apache.org/repos/asf/synapse/trunk/java/modules/core/src/main/java/org/apache/synapse/SynapseConstants.java"; + id="or6m">SynapseConstant class</a> (under the endpoint failure section). The configuration section for this + state called <b><i>markForSuspension</i></b>.If a previously defined error code is and if it does have a positive + retrieve count (see the configuration section below) the endpoint will be retrieve again(the number of time to + retrieve can be configured using the same configuration element) and if it fails in further attempts it will transfer + into <b>Suspended</b> state. </p> +<p><b>[3] Suspended</b> - When invoking the endpoint if a previously defined error code for Suspended state is returned + or a if a TimeOut endpoint fails in further attempts the endpoint is said to be in <b>Suspended</b> state. + The endpoint can goes into Active state once the suspend duration is over. The configuration section + called <b><i>suspendOnFailure</i></b>.</p> +<p><b>[4] Switch Off</b> - The endpoint is moved into maintains mode. +</p> + +<p> +A state transfer between any state to <b>Switch off</b> state can be done only manually using JMX based API. + And also an endpoint which is in <b>SwitchOff</b> state can only transfer into <b>Active state</b> again using + the JMX based API. See section on using JMX based API to learn how to do this. +</p> + +<p> +The state transition between states can be shown as follows. +</p> + +<div id="endpoint-state" style="text-align: left;"><img style="width: 648px; height: 267.568px;" + alt="endpoint-state-image" src="../resources/images/endpoint-state.png"/></div> +<p>Figure1: The state transition between states in an endpoint</p> + +<h4>Using jconsole to manage state transition between states</h4> + +<p>The jconsole tool is a JMX-compliant graphical tool for monitoring a Java virtual machine. If you have installed + java you'll automatically get this tool. We'll add an endpoint (name 'ep1') and monitor the states transition + between states in ep1 +</p> + +<p>1. Add an address endpoint called 'ep1'. Refer endpoint userguide to see how this can be done.</p> +<p>2. Start jconsole by typing jconsole at your termnial, if you encounter any problem please consult your operatying + system guide. You'll see the following console once you select Mbeans tab. </p> + +<div id="jconsole" style="text-align: left;"><img style="width: 648px; height: 414.212px;" + alt="jconsole-mbean-tab" src="../resources/images/jconsole-mbean.png"/></div> + +<p>Figure2: Jconsole Mbeans tab</p> +<p>3.Go to org.apache.synpase menu from left hand and expand it. You'll see the following figure with the + endpoint ep1 that we just added. +</p> + +<div id="jconsole-endpoint" style="text-align: left;"><img style="width: 648px; height: 560.852px;" + alt="endpoint-mbean-show" src="../resources/images/endpoint-mbean.png"/></div> +<p>Figure3: Endpoint Mbean is selected </p> + +<p>4. Select the ep1 endpoint and you'll see the information related to this endpoint and please note that the state + is given as active as the first entry and value is set to true. The endpoint is in active state. +</p> +<div id="endpoint-info" style="text-align: left;"><img style="width: 648px; height: 402.848px;" + alt="endpoint-information-image" src="../resources/images/endpoint-info.png"/></div> +<p>Figure4: The ep1 endpoint attributes. The endpoint is active.</p> + +<p>5. Now go to the Operations tab and switch off the endpoint. You'll see a message saying the + operation was successful. +</p> +<div id="endpoin-off" style="text-align: left;"><img + alt="endpoint-off-image" style="width: 648px; height: 713.229px;" src="../resources/images/endpoint-off.png"/></div> +<p>Figure5: Switching off the endpoint.</p> + +<p>You'll also see a INFO level log message saying that the endpoint was switched off manually.</p> + +<p><font style="font-family: Courier New;" size="3">[2009-06-23 12:18:21,149] INFO - EndpointContext Manually switching off endpoint : ep1</font></p> + +<p>6. Next again switch back to Attributes tab and see the state of the endpoint after refreshing it. You'll see + endpoint is inactive and the endpoint is in switch off state. At this point if you try to use a client which + use this endpoint you'll see it fails since the endpoint is down. You can use a similar approach activate the + endpoint back. +</p> + +<div id="y.8h" style="text-align: left;"><img style="width: 648px; height: 336.767px;" + alt="endpoint-switched-off-image" src="../resources/images/endpoint-turn-off.png"/></div> +<p>Figure6: Endpoint is in Switch off state.</p> + +<h3>Address Endpoint</h3> +<p>Address endpoint is an endpoint defined by specifying the EPR (Endpoint Reference) and other attributes + of the configuration.</p> + +<h4>Address endpoint configuration</h4> + +<pre xml:space="preserve"> +<address uri="<i>endpoint address</i>" [format="soap11|soap12|pox|get"] [optimize="mtom|swa"] + [encoding="<i>charset encoding</i>"] + [statistics="enable|disable"] [trace="enable|disable"]> + + <enableRM [policy="<i>key</i>"]/>? + <enableSec [policy="<i>key</i>"]/>? + <enableAddressing [version="final|submission"] [separateListener="true|false"]/>? + + <timeout> + <duration><i>timeout duration in seconds</i></duration> + <action>discard|fault</action> + </timeout>? + + <markForSuspension> + [<errorCodes>xxx,yyy</errorCodes>] + <retriesBeforeSuspension>m</retriesBeforeSuspension> + <retryDelay>d</retryDelay> + </markForSuspension> + + <suspendOnFailure> + [<errorCodes>xxx,yyy</errorCodes>] + <initialDuration>n</initialDuration> + <progressionFactor>r</progressionFactor> + <maximumDuration>l</maximumDuration> + </suspendOnFailure> +</address> +</pre> + +<h5>Address endpoint attributes</h5> +<div><table class="" id="grrh" border="1" cellpadding="3" cellspacing="0" + width="1488"><tbody> + <tr><td width="50%">uri<br/></td><td width="50%">EPR of the target endpoint. + See the table below for a possible list of transports.<br/></td></tr> + <tr><td width="50%">format<br/></td><td width="50%">Message format for the endpoint.<br/></td></tr> + <tr><td width="50%">optimize<br/></td><td width="50%">Method to optimize the attachments.<br/></td></tr> + <tr><td width="50%">encoding<br/></td><td width="50%">The charset encoding to use for the endpoint.<br/></td></tr> + <tr><td width="50%">statistics<br/></td><td width="50%">This enables statistics for the endpoint.<br/></td></tr> + <tr><td width="50%">trace<br/></td><td width="50%">This enables trace for the endpoint.<br/></td></tr> +</tbody></table></div> + +<h5>QoS for the endpoint</h5> +<p>QoS (Quility of service) aspects such as WS-RM(WS-Reliable messaging), WS-Security and WS-Addressing may be + enabled on messages send to an endpoint using <b>enableRM, enableSec</b> and <b>enableAddressing</b> + elements. Optionally, the WS-RM and WS-Security policies could be specified using <i><b>policy</b></i> attribute. +</p> +<h5>QoS configuration</h5> + +<div><table class="" id="v1c." border="1" cellpadding="3" cellspacing="0" width="1490"> + <tbody> + <tr><td width="50%">enableRM [policy="<i>key</i>"]<br/></td><td width="50%">This enables WS-Reliable messaging + for the message which goes for the endpoint. The optional <i>policy</i> attribute specify the WS-RM + policy.<br/></td></tr> + <tr><td width="50%">enableSec [policy="<i>key</i>"]<br/></td><td width="50%">This enables WS-Security for + the message which goes for the endpoint. The optional <i>policy</i> attribute specify the WS-Security + policy.<br/></td></tr> + <tr><td width="50%">enableAddressing [version="final | submission"] [seperateListener=" true | false"]<br/> + </td><td width="50%">This enables WS-Addressing for the message which goes for the endpoint. User can specify + to have seperate listener with version final or submission. <br/></td></tr> + </tbody></table></div> + +<h5>Endpoint timeout</h5> +<p>Address(and also WSDL) endpoints can timeout if the response fails to arrive at Synapse by a predefined + timeout duration specified in seconds. The timeout action specifies whether to discard reponse that arives + later, or to trigger a fault. Synapse has a periodic timeout handler that triggers itself at each 15 seconds + interval. Thus endpoint timeout will have a +/- erroce on trigger time. Though this can be minimized by + setting a System property "synapse.timeout_handler_interval"(This property can be set in synapse.properties + synpase property file which is located in conf directory inside repository once you unzipped WSO2 ESB ) + to a millisecond duration below the desired endpoint timeout, <b>care must be taken as a lesser value may have a + higher overhead on the system.</b></p> + +<h5>timeout configuration</h5> +<div><table class="" id="cs2_" border="1" cellpadding="3" cellspacing="0" width="1493"> + <tbody> + <tr><td width="50%">duration<br/></td><td width="50%">Timeout duration in second. <br/></td></tr> + <tr><td width="50%">action<br/></td><td width="50%">Once a timeout occurs the action to perform, avilable + options are <i>discard</i> (discard the response which arrives late) or <i>fault</i> (trigger a fault) + .<br/></td></tr> + </tbody></table></div> + +<h5>Marking endpoint for suspension</h5> +<p>As described before (see description on Timeout state above) this configuration element describes the configuration + for a timeout endpoint. +</p> +<h5>markForSuspension configuration</h5> +<div><table class="" id="aliw" border="1" cellpadding="3" cellspacing="0" width="1496"> + <tbody><tr><td width="50%">errorCodes<br/></td><td width="50%">A comma separated error code list which can be + returned by the endpoint. See <a title="SynpaseConstant" target="_blank" + href="https://svn.apache.org/repos/asf/synapse/trunk/java/modules/core/src/main/java/org/apache/synapse/SynapseConstants.java"; + >SynpaseConstant</a> class for a possible list of error codes. <br/></td></tr> + <tr><td>retriesBeforeSuspension</td><td>Number of retries before go into suspended + state.<br/></td></tr> + <tr><td>retryDelay</td><td><font size="3">The delay between each try.<br/></font></td></tr> + </tbody></table></div> +<h5>Suspending endpoint on failure</h5> +<p>Address (and also WSDL) endpoint can be put into suspended state if it is detected as failed. An endpoint that + fails may be suspended for a specified duration after such a failure, during which new messages will not be + processed through the endpoint. The amount of time waiting before next attempt follows a + <a title="geometric series" target="_blank" href="http://en.wikipedia.org/wiki/Geometric_series"; id="r-md">geometric series.</a> + <br/> +Ex: Suppose T<sub>1</sub>, T<sub>2</sub>, T<sub>3</sub>....T<sub>n</sub> are suspended duration before next + attempt. The T<sub>1</sub>, T<sub>2</sub>, T<sub>3</sub>...T<sub>n</sub> can be defined as follows:<br/> +T<sub>1</sub> = a <br/> +T<sub>2</sub> = a + ar<br/> +T<sub>3</sub> = a + ar + ar<sup>2</sup><br/> +.<br/> +.<br/> +.<br/> +T<sub>n</sub> = a + ar<sup>2</sup> + ... + ar<sup>n</sup><br/> +<br/> +where 'a' is the initially defined duration to suspend the endpoint for first fail attempt and 'r' is the + progression factor (which is specified by the user) by which the user need to increase the previous value. + <br/> +</p> + +<h5>suspendOnFailure configuration</h5> +<div> +<table class="" id="ieu9" border="1" cellpadding="3" cellspacing="0" width="1499"> +<tbody> +<tr> +<td width="50%">errorCode<br/> +</td> +<td width="50%">A comma separated error code list which can be returned by the endpoint. See <a title="SynpaseConstant" target="_blank" + href="https://svn.apache.org/repos/asf/synapse/trunk/java/modules/core/src/main/java/org/apache/synapse/SynapseConstants.java"; + >SynpaseConstant</a> class for a possible list of error codes. <br/> +</td> +</tr> +<tr> +<td width="50%"> +initialDuration +</td> +<td width="50%">Initial duration to suspend the endpoint.<br/> +</td> +</tr> +<tr> +<td width="50%"> +progressionFactor +</td> +<td width="50%">The progression factor for the geometric series. See above for a more detailed description.<br/> +</td> +</tr> +<tr> +<td width="50%"> +maximumDuration +</td> +<td width="50%">Maximum duration to suspend the endpoint. <br/> +</td> +</tr> +</tbody> +</table> +</div> + +<h5>Following are the sample address URI definitions. </h5> +<div> +<table class="" id="aq95" border="1" cellpadding="3" cellspacing="0" width="1495"> +<tbody> +<tr> +<td width="50%">Transport<br/> +</td> +<td width="50%">Sample Address<br/> +</td> +</tr> +<tr> +<td width="50%">HTTP<br/> +</td> +<td width="50%">http://localhost:9000/services/SimpleStockQuoteService</td> +</tr> +<tr> +<td width="50%">JMS<br/> +</td> +<td width="50%">jms:/SimpleStockQuoteService?<br/> + transport.jms.ConnectionFactoryJNDIName=QueueConnectionFactory&<br/> + java.naming.factory.initial=org.apache.activemq.jndi.ActiveMQInitialContextFactory&<br/> + java.naming.provider.url=tcp://localhost:61616&<br/> + transport.jms.DestinationType=topic</td> +</tr> +<tr> +<td width="50%">Mail<br/> +</td> +<td width="50%">mailto:gu...@host</td> +</tr> +<tr> +<td width="50%">VFS<br/> +</td> +<td width="50%">vfs:file:///home/user/directory<br/> + vfs:file:///home/user/file<br/> + vfs:ftp://guest:gu...@localhost/directory?vfs.passive=true +</td> +</tr> +<tr> +<td width="50%">FIX<br/> +</td> +<td width="50%">fix://host:port?BeginString=FIX4.4&SenderCompID=WSO2&TargetCompID=APACHE<br/> +<br/> +</td> +</tr> +</tbody> +</table> +</div> + +<h3>Default Endpoint</h3> +<p>Default endpoint is an endpoint defined for adding QoS and other configurations + to the endpoint which is resolved from the 'To' address of the message context. + All the configurations such as message format for the endpoint, the method + to optimize attachments, reliable messaging, security policies for the endpoint + can be specified as in the Address Endpoint. This endpoint differs from the address + endpoint only in the uri attribute which will not be present in this endpoint. + Following section describes the configuration of a default endpoint.</p> +<h4>Default endpoint configuration</h4> +<pre xml:space="preserve"> +<default [format="soap11|soap12|pox|get"] [optimize="mtom|swa"] + [encoding="<i>charset encoding</i>"] + [statistics="enable|disable"] [trace="enable|disable"]> + + <enableRM [policy="<i>key</i>"]/>? + <enableSec [policy="<i>key</i>"]/>? + <enableAddressing [version="final|submission"] [separateListener="true|false"]/>? + + <timeout> + <duration><i>timeout duration in seconds</i></duration> + <action>discard|fault</action> + </timeout>? + + <markForSuspension> + [<errorCodes>xxx,yyy</errorCodes>] + <retriesBeforeSuspension>m</retriesBeforeSuspension> + <retryDelay>d</retryDelay> + </markForSuspension> + + <suspendOnFailure> + [<errorCodes>xxx,yyy</errorCodes>] + <initialDuration>n</initialDuration> + <progressionFactor>r</progressionFactor> + <maximumDuration>l</maximumDuration> + </suspendOnFailure> +</default> +</pre> + +<h3>WSDL endpoint</h3> +<p>WSDL endpoint is an endpoint definition based on a specified WSDL document. The WSDL document can be specified + either as a URI or as an inlined definition within the configuration. The service and port name + containing the target EPR has to be specified with the 'service' and 'port' (or 'endpoint') attributes + respectively. enableRM, enableSec, enableAddressing, suspendDurationOnFailure and timeout elements are same + as for an Address endpoint.</p> + +<h4>WSDL endpoint configuration</h4> +<pre xml:space="preserve"> +<wsdl [uri="wsdl-uri"] service="qname" port/endpoint="qname"> + <wsdl:definition>...</wsdl:definition>? + <wsdl20:description>...</wsdl20:description>? + <enableRM [policy="key"]/>? + <enableSec [policy="key"]/>? + <enableAddressing/>? + + <timeout> + <duration><i>timeout duration in seconds</i></duration> + <action>discard|fault</action> + </timeout>? + + <markForSuspension> + [<errorCodes>xxx,yyy</errorCodes>] + <retriesBeforeSuspension>m</retriesBeforeSuspension> + <retryDelay>d</retryDelay> + </markForSuspension> + + <suspendOnFailure> + [<errorCodes>xxx,yyy</errorCodes>] + <initialDuration>n</initialDuration> + <progressionFactor>r</progressionFactor> + <maximumDuration>l</maximumDuration> + </suspendOnFailure> +</wsdl> +</pre> + +<h3>Load balance Endpoint</h3> +<p>A Load balanced endpoint distributes the messages (load) arriving at it + among a set of listed endpoints or static members by evaluating the load balancing policy + and any other relevant parameters. The policy attribute of the load balance + element specifies the load balance policy (algorithm) to be used for + selecting the target endpoint or static member. Currently only the roundRobin policy is + supported. The failover attribute determines if the next endpoint or static member should be + selected once the currently selected endpoint or static member has failed, and defaults to + true. The set of endpoints or static members amongst which the load has to be distributed + can be listed under the 'loadBalance' element. These endpoints can belong to any + endpoint type mentioned in this document. For example, failover endpoints + can be listed inside the load balance endpoint to load balance between + failover groups etc. The loadbalance element cannot have both endpoint & member child + elements in the same configuration. In the case of the member child element, the <i>hostName</i>, + <i>httpPort</i> and/or <i>httpsPort</i> attributes could be specified.</p> + <p> + The optional 'session' element makes the endpoint a session affinity based + load balancing endpoint. If it is specified, sessions are bound to + endpoints in the first message and all successive messages for those + sessions are directed to their associated endpoints. Currently there are two types + of sessions supported in SAL endpoints. Namely HTTP transport based session + which identifies the sessions based on http cookies and the client session which + identifies the session by looking at a SOAP header sent by the client with the QName + '{http://ws.apache.org/ns/synapse}ClientID'. The 'failover' attribute mentioned above + is not applicable for session affinity based endpoints and it is always + considered as set to false. If it is required to have failover behavior in session + affinity based load balance endpoints, list failover endpoints as the target endpoints. + </p> + +<h4>Load balance endpoint configuration</h4> +<pre xml:space="preserve"> +<session type="http|simpleClientSession"/>? +<loadBalance [policy="roundRobin"] [algorithm="impl of org.apache.synapse.endpoints.algorithms.LoadbalanceAlgorithm"] + [failover="true|false"]> + <endpoint .../>+ + <member hostName="host" [httpPort="port"] [httpsPort="port2"]>+ +</loadBalance> +</pre> + + +<h3>Failover Endpoint</h3> +<p>Failover endpoints send messages to the listed endpoints with the following failover behavior. At the start, the + first listed endpoint is selected as the primary and all other endpoints are treated as backups. + Incoming messages are always sent only to the primary endpoint. If the primary endpoint fails, + next active endpoint is selected as the primary and failed endpoint is marked as inactive. + Thus it sends messages successfully as long as there is at least one active endpoint among the listed + endpoints.</p> + +<h4>Failover endpoint configuration</h4> +<pre xml:space="preserve"> +<failover> + <endpoint .../>+ +</failover> +</pre> + +<h3>Dynamic Load balance Endpoint</h3> +<p>A Dynamic Load balanced endpoint distributes the messages (load) arriving at it among a application members by + evaluating the load balancing policy and any other relevant parameters. These application members will be + discovered using the membershipHandler class. Generally, this class will use a group communication mechanism + to discover the application members. The class attribute of the membershipHandler element should be an + implementation of org.apache.synapse.core.LoadBalanceMembershipHandler. membershipHandler specific properties + can be specified using the property elements. The policy attribute of the dynamicLoadbalance element specifies + the load balance policy (algorithm) to be used for selecting the next member to which the message has to be + forwaded to. Currently only the roundRobin policy is supported. The failover attribute determines if the next + member should be selected once the currently selected member has failed, and defaults to true.</p> +<h4>Dynamic Load balance endpoint configuration</h4> +<pre xml:space="preserve"> +<dynamicLoadBalance [policy="roundRobin"] [failover="true|false"]> + <membershipHandler + class="impl of org.apache.synapse.core.LoadBalanceMembershipHandler"> + <property name="name" value="value"/> + </membershipHandler> +</dynamicLoadBalance> +</pre> + + + +</body> +</html> \ No newline at end of file _______________________________________________ Esb-java-dev mailing list [email protected] https://wso2.org/cgi-bin/mailman/listinfo/esb-java-dev
