This topic explains how to configure message proxies (and recording proxies) that send and receive messages over the JMS transport.
In this section:
See JMS Prerequisites.
When traffic is being exchanged over queues, the assumption is that there is a client application which sends a request to a client destination queue and a server application that receives that message from the queue, then sends another (reply) message onto a second queue for the client to receive.
With that scenario in mind, Parasoft Virtualize uses a "man-in-the-middle" (a.k.a. proxy) approach between the client and the server, so two extra queues are needed on the messaging provider in order to facilitate that mediation. Virtualize proxies will receive messages from where the client places them, record the message contents (if recording is enabled), then put the message on the queue where the server will receive it. Similarly, the server sends the message to a queue where the proxy picks it up, records it (if recording is enabled), and places it back on the queue where the client is expecting the reply response.
As a result, it is necessary to allocate two additional queues and either:
- Adjust the client application to communicate over these two new queues (with the proxy connections configured for them).
- Adjust the server application to use the two other queues.
Only one of the two application queues needs to be modified.
Specifying JMS Settings
Specify your JMS settings as follows:
- In the Proxy Connection Settings dialog, choose JMS for Proxy Type.
- Specify the JMS type (Queues/Point-to-Point or Topics/Publish-and-Subscribe).
If you are defining the connection settings in this panel (rather than referencing previously-defined global JMS settings as described in Using Global JMS Connections), enter JMS provider details in the Local Settings area. You can specify the Provider URL, Initial context class, and Connection factory (be sure to add the related jars to the Virtualize classpath), as well as authentication and any additional initial context JNDI properties you want to apply.
Using multiple JMS connections in a single proxy
If you want to configure connections to different JMS servers within a single proxy (e.g., you want a specific proxy connection use two queues that are deployed on two different JMS servers), create a global JMS connection for each connection, then select the appropriate connections as you configure the proxy.
- Specify the connection details. You can either enter the settings for each connection in this panel (via the Local Settings option) or reference a global JMS connection defined at the Virtualize server level (see Using Global JMS Connections for details).
For Queues (Point-to-Point): Virtualize will capture messages sent to the client Destination queue and forward them to the server Reply to queue for processing. The server Destination queue is the queue that the server will place a response message on (after processing the request message). Virtualize will capture these messages and forward them to the client Reply to queue.
Queue Configuration Details
See Configuring Queues For Recording for tips on how to configure recording in different scenarios.
- For Topics (Publish-and-Subscribe): Virtualize monitors incoming requests on the client Subscribe topic and outgoing responses on the server Publish topic.
- Modify the Use JMSReplyTo for Response setting if desired. It specifies whether to use the message's JMSReplyToQueueName header to determine where the proxy sends the response.
- If it is enabled, values from the incoming request will be used to determine where to send the response.
- If it is not enabled, the response will be sent to the queue specified in the UI; the values in the JMS message header will be ignored.
- Modify the Worker count setting if desired.
Adjusting the Worker Count
Each worker creates its own connection to the JMS provider. Whenever a proxy is deployed/redeployed with a worker count that is higher than the default value of 1, you should see messages like "Started x listener(s)" in the Console (where x is the number of workers configured).
Increasing the worker count can help performance under concurrency. The entire message processing chain of the proxy is parallelized, so each worker thread will do message correlations, response message generation, etc. in parallel with other threads. However, beware that if you provide a high worker count, deploying/undeploying/redeploying a proxy will take longer because there are more connections to create/destroy. Also, it is possible that the JMS provider has a limit on how many concurrent connections to allow. You should not exceed what is configured/allowed by your infrastructure.
The worker count feature is equivalent to the “maxThreads” attribute in Tomcat server.xml; see Configuring SSL (HTTPS) for the Virtualize Server for details on where to find the server.xml for Virtualize’s Tomcat.
When subjecting Virtualize to a high number of concurrent virtual users (i.e. during a load test), you can usually expect better performance by increasing these values.
Using Global JMS Connections
Global JMS settings that apply across a specific Virtualize server can be defined at the server level, then referenced here. See Connections Tab for details.
To use a global JMS connection, select it from the appropriate Queue or Topic box.
To review the details of a predefined global connection, click View settings.
Queue Configuration Tips
See Configuring Queues For Recording for tips on how to configure queues in different scenarios.