cics-java-liberty-springboot-asynchronous

This sample project demonstrates a Spring Boot application running asynchronous operations on CICS-enabled threads. It is intended for deployment inside an IBM CICS Liberty JVM server.

Prerequisites

CICS TS V5.3 or later
A configured Liberty JVM server in CICS
Java SE 1.8 or later on the workstation
An Eclipse development environment on the workstation (optional)
Either Gradle or Apache Maven on the workstation (optional if using Wrappers)

Downloading

Clone the repository using your IDEs support, such as the Eclipse Git plugin
or, download the sample as a ZIP and unzip onto the workstation

Tip: Eclipse Git provides an 'Import existing Projects' check-box when cloning a repository.

Check dependencies

Before building this sample, you should verify that the correct CICS TS bill of materials (BOM) is specified for your target release of CICS. The BOM specifies a consistent set of artifacts, and adds information about their scope. In the example below the version specified is compatible with CICS TS V5.5 with JCICS APAR PH25409, or newer. That is, the Java byte codes built by compiling against this version of JCICS will be compatible with later CICS TS versions and subsequent JCICS APARs.

You can browse the published versions of the CICS BOM at Maven Central.

Gradle (build.gradle):

compileOnly enforcedPlatform("com.ibm.cics:com.ibm.cics.ts.bom:5.5-20200519131930-PH25409")

Maven (POM.xml):

<dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>com.ibm.cics</groupId>
      <artifactId>com.ibm.cics.ts.bom</artifactId>
      <version>5.5-20200519131930-PH25409</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
</dependencyManagement>

Building

You can build the sample using an IDE of your choice, or you can build it from the command line. For both approaches, using the supplied Gradle or Maven wrapper is the recommended way to get a consistent version of build tooling.

On the command line, you simply swap the Gradle or Maven command for the wrapper equivalent, gradlew or mvnw respectively.

For an IDE, taking Eclipse as an example, the plug-ins for Gradle buildship and Maven m2e will integrate with the "Run As..." capability, allowing you to specify whether you want to build the project with a Wrapper, or a specific version of your chosen build tool.

The required build-tasks are typically clean bootWar for Gradle and clean package for Maven. Once run, Gradle will generate a WAR file in the build/libs directory, while Maven will generate it in the target directory.

Note: When building a WAR file for deployment to Liberty it is good practice to exclude Tomcat from the final runtime artifact. We demonstrate this in the pom.xml with the provided scope, and in build.gradle with the providedRuntime() dependency.

Note: If you import the project to your IDE, you might experience local project compile errors. To resolve these errors you should run a tooling refresh on that project. For example, in Eclipse: right-click on "Project", select "Gradle -> Refresh Gradle Project", or right-click on "Project", select "Maven -> Update Project...".

Tip: In Eclipse, Gradle (buildship) is able to fully refresh and resolve the local classpath even if the project was previously updated by Maven. However, Maven (m2e) does not currently reciprocate that capability. If you previously refreshed the project with Gradle, you'll need to manually remove the 'Project Dependencies' entry on the Java build-path of your Project Properties to avoid duplication errors when performing a Maven Project Update.

Gradle Wrapper (command line)

Run the following in a local command prompt:

On Linux or Mac:

./gradlew clean bootWar

On Windows:

gradlew.bat clean bootWar

This creates a WAR file inside the build/libs directory.

Maven Wrapper (command line)

Run the following in a local command prompt:

On Linux or Mac:

./mvnw clean package

On Windows:

mvnw.cmd clean package

This creates a WAR file inside the target directory.

Deploying to a CICS Liberty JVM server

Ensure you have the following features defined in your Liberty server.xml:

servlet-3.1 or servlet-4.0 depending on the version of Java EE in use.
concurrent-1.0.
cicsts:security-1.0 if CICS security is enabled.

A template server.xml is provided here.

Note: servlet-4.0 will only work for CICS TS V5.5 or later

Deploying with CICS bundles

Copy and paste the built WAR from your target or build/libs directory into a Eclipse CICS bundle project.
Create a new WAR bundlepart that references the WAR file.
Deploy the CICS bundle project from CICS Explorer using the Export Bundle Project to z/OS UNIX File System wizard.

Deploying with Liberty configuration

Manually upload the WAR file to zFS
Add an <application> element to the Liberty server.xml to define the web application with access to all authenticated users. For example the following application element can be used to install a WAR, and grant access to all authenticated users if security is enabled:

<application id="cics-java-liberty-springboot-asynchronous-0.1.0"
    location="${server.config.dir}/springapps/cics-java-liberty-springboot-asynchronous-0.1.0.war"
    name="cics-java-liberty-springboot-asynchronous-0.1.0" type="war">
    <application-bnd>
        <security-role name="cicsAllAuthenticated">
            <special-subject type="ALL_AUTHENTICATED_USERS"/>
        </security-role>
    </application-bnd>
</application>

Running the Sample

Ensure the web application started successfully in Liberty by checking for msg CWWKT0016I in the Liberty messages.log:
- A CWWKT0016I: Web application available (default_host): http://zos.example.com:9080/cics-java-liberty-springboot-asynchronous-0.1.0
- I SRVE0292I: Servlet Message - [cics-java-liberty-springboot-asynchronous-0.1.0]:.2 Spring WebApplicationInitializers detected on classpath
Copy the context root from message CWWKT0016I along with the REST service suffix 'test' into the browser e.g. http://zos.example.com:9080/cics-java-liberty-springboot-asynchronous-0.1.0/test.
If successful, the application will spawn 10 asynchronous requests (5 to each of two services). You can check the output from these asynchronous methods by viewing the TSQ called SPRINGTHREADS and/or messages.log. One way to achieve this is through the CICS command "CEBR SPRINGTHREADS". You should see a number of entries (one per thread) for each of the two services (methods) we call: "Task <number>: Hello from asynchronous service<no>(<thread>)". Although each service is spawned 5 times in round-robin fashion the execution of those services is asynchronous and on separate CICS-enabled threads - so the TSQ writes will be of an unpredictable order.

License

This project is licensed under Eclipse Public License - v 2.0.

cicsdev/cics-java-liberty-springboot-asynchronous