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| |
| <document> |
| <properties> |
| <title>Apache Synapse - Sample 651</title> |
| </properties> |
| <body> |
| <section name="Sample 651: Priority Based Dispatching at Transport Level"> |
| <p> |
| For this sample we will be using the same Synapse configuration used in |
| <a href="sample150.html">sample 150</a>. In addition we will be using the following |
| priority configuration for the Synapse NHTTP transport. |
| </p> |
| <div class="xmlConf"><priorityConfiguration> |
| <priorityExecutor> |
| <!-- two priorities specified with priority 10 and 1. Both priority messages has a queue depth of 100 --> |
| <queues isFixedCapacity="true" nextQueue="org.apache.synapse.commons.executors.PRRNextQueueAlgorithm"> |
| <queue size="100" priority="10"/> |
| <queue size="100" priority="1"/> |
| </queues> |
| <!-- these are the default values, values are put here to show their availability --> |
| <threads core="20" max="100" keep-alive="5"/> |
| </priorityExecutor> |
| |
| <!-- if a message comes that we cannot determine priority, we set a default priority of 1 --> |
| <conditions defaultPriority="1"> |
| <condition priority="10"> |
| <!-- check for the header named priority --> |
| <equal type="header" source="priority" value="5"/> |
| </condition> |
| <condition priority="1"> |
| <equal type="header" source="priority" value="1"/> |
| </condition> |
| </conditions> |
| </priorityConfiguration></div> |
| <subsection name="Objective"> |
| <p> |
| Demonstrate priority based dispatching capabilities of the Synapse NHTTP |
| transport |
| </p> |
| </subsection> |
| <subsection name="Pre-requisites"> |
| <p> |
| <ul> |
| <li> |
| Deploy the SimpleStockQuoteService in the sample Axis2 server and start Axis2 |
| </li> |
| <li> |
| Open axis2.xml file in repository/conf directory and uncomment the |
| following parameter in the NHTTP transport receiver configuration. |
| <br/><strong>priorityConfigFile</strong> |
| <br/>Set the value to repository/conf/sample/resources/priority/priority-configuration.xml |
| </li> |
| <li> |
| Start Synapse using the configuration numbered 150 (repository/conf/sample/synapse_sample_150.xml) |
| <div class="command"> |
| Unix/Linux: sh synapse.sh -sample 150<br/> |
| Windows: synapse.bat -sample 150 |
| </div> |
| </li> |
| </ul> |
| </p> |
| </subsection> |
| <subsection name="Executing the Client"> |
| <p> |
| Priority is applied only when synapse is loaded with enough messages to consume |
| all of its core worker threads. So to observe the priority based mediation, it is |
| required to use a load testing tool like JMeter, SOAP UI or Apache bench. |
| </p> |
| <p> |
| In this sample, client should send a HTTP header that specifies the priority of |
| the message.This header name is 'priority'. This header is retrieved in the synapse |
| configuration using the $trp:priority XPath expression. Then it is matched against |
| the value 1. If it has the value 1, message is executed with priority 1. Otherwise |
| the message is executed with priority 10. |
| </p> |
| <p> |
| Messages with different priorities are put into different priority queues. Then they |
| are mediated in a manner so that high priority messages are always processed first. |
| </p> |
| <p> |
| Here are two sample SOAP requests that can be used to invoke the service using a |
| tool like JMeter, or Apache Bench. For SOAP UI, user can use the WSDL |
| repository/conf/sample/resources/proxy/sample_proxy_1.wsdl to create the request. |
| The only difference between the two requests shown here is the symbol. One |
| has the symbol as IBM and other has MSFT. For one type of requests set the priority |
| header to 1 and for the next set the priority header to 10. Then load Synapse with |
| a large volume of traffic consisting of both types of requests using the load testing tool. |
| Back end Axis2 server prints the symbol of the incoming requests. User should be |
| able to see more of the high priority symbol. |
| </p> |
| <div class="xmlConf"><soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"> |
| <soapenv:Header xmlns:wsa="http://www.w3.org/2005/08/addressing"> |
| <wsa:To>http://localhost:8281/services/SimpleStockQuoteService</wsa:To> |
| <wsa:MessageID>urn:uuid:1B57D0B0BF770678DE1261165228620</wsa:MessageID> |
| <wsa:Action>urn:getQuote</wsa:Action> |
| </soapenv:Header> |
| <soapenv:Body> |
| <m0:getQuote xmlns:m0="http://services.samples"> |
| <m0:request> |
| <m0:symbol>IBM</m0:symbol> |
| </m0:request> |
| </m0:getQuote> |
| </soapenv:Body> |
| </soapenv:Envelope></div> |
| <div class="xmlConf"><soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"> |
| <soapenv:Header xmlns:wsa="http://www.w3.org/2005/08/addressing"> |
| <wsa:To>http://localhost:8281/services/SimpleStockQuoteService</wsa:To> |
| <wsa:MessageID>urn:uuid:1B57D0B0BF770678DE1261165228620</wsa:MessageID> |
| <wsa:Action>urn:getQuote</wsa:Action> |
| </soapenv:Header> |
| <soapenv:Body> |
| <m0:getQuote xmlns:m0="http://services.samples"> |
| <m0:request> |
| <m0:symbol>MSFT</m0:symbol> |
| </m0:request> |
| </m0:getQuote> |
| </soapenv:Body> |
| </soapenv:Envelope></div> |
| <p> |
| In this sample, priority based mediation takes place at the transport level |
| itself (before the message is even received by the mediation engine). High |
| priority messages will reach the service bus first. |
| </p> |
| </subsection> |
| </section> |
| <p><a href="../samples.html">Back to Catalog</a></p> |
| </body> |
| </document> |
