Service types

The IBM® MQ service provider exposes IBM MQ queues and topics, and the applications that are behind them, as services.

zosConnect-2.0 Applies to zosConnect-2.0.

Services can be one-way or two-way and are created by using the API toolkit. For more information, see Build a service archive with the build toolkit. After a service is created using the API toolkit, the build toolkit can then be used to create this service for use in a DevOps workflow environment.

Services can be created by one of the following methods:
  1. Use the API toolkit. This method is preferred, because it provides enhanced capabilities such as enabling MQ messages to be greater than 32K. When a service is created with the API toolkit, it can later be built by the build toolkit. For more information, see Build a service archive with the build toolkit.
  2. Manually create a properties file that describes the service. The properties file is then used by the build toolkit to create the service.
One-way service
A one-way service can be used to provide a RESTful API for a single IBM MQ queue or topic and supports the sending of messages to either a queue or a topic, or receiving messages from a queue.
Figure 1. One-way service
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One-way services for sending messages can be created in the API toolkit by creating a service project of type MQ One-Way Service for Sending Messages, or by using a properties file with a messagingAction value of mqput. When a RESTful client sends an HTTP request with a JSON payload to a service of this type, the service sends a message with the payload as the message body, to the target queue or topic.

One-way services for receiving messages can be created in the API toolkit by creating a service project of type MQ One-Way Service for Receiving Messages, or by using a properties file with a messagingAction value of mqget. When a RESTful client sends an HTTP request with no payload to a service of this type, the service attempts to destructively get an available message from an IBM MQ queue. If a message was available, the payload of the message is returned as the response body of the HTTP request.

Two-way service
A two-way service allows a RESTful client to perform request-reply messaging on a pair of queues.
Figure 2. Two-way service
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The client sends an HTTP request, specifying a JSON payload. The service takes the payload, optionally converts it to a different format such as a COBOL copybook, and sends it as a message to a request queue.

A backend application gets the message, processes it and generates a response, which is placed on a reply queue. The service locates this message, takes its payload, optionally converts it to JSON and returns it as the response body of the HTTP request.