The cmt quickstart demonstrates Container-Managed Transactions (CMT), showing how to use transactions managed by the container.

What is it?

The cmt quickstart demonstrates how to use container-managed transactions (CMT), which are transactions managed by the container in Red Hat JBoss Enterprise Application Platform. It is a fairly typical scenario of updating a database and sending a JMS message in the same transaction. A simple MDB is provided that prints out the message sent but this is not a transactional MDB and is purely provided for debugging purposes.

Aspects touched upon in the code:

  • XA transaction control using the container managed transaction annotations

  • XA access to the standard default datasource using the JPA API

  • XA access to a JMS queue

After you complete this quickstart, you are invited to run through the following quickstarts:

  • jts - The jts quickstart builds upon this quickstart by distributing the CustomerManager and InvoiceManager.

  • jts-distributed-crash-rec - The crash recovery quickstart builds upon the jts quickstart by demonstrating the fault tolerance of JBoss EAP.

What are Container Managed Transactions?

Prior to EJB, getting the right incantation to ensure sound transactional operation of the business logic was a highly specialized skill. Although this still holds true to a great extent, EJB has provided a series of improvements to allow simplified transaction demarcation notation that is therefore easier to read and test.

With CMT, the EJB container sets the boundaries of a transaction. This differs from BMT (bean-managed transactions), where the developer is responsible for initiating and completing a transaction using the begin, commit, and rollback methods on a javax.transaction.UserTransaction.

What Makes This an Example of Container Managed Transactions?

Take a look at org.jboss.as.quickstarts.cmt.ejb.CustomerManagerEJB. You can see that this stateless session bean has been marked up with the @javax.ejb.TransactionAttribute annotation.

The following options are available for this annotation.

Required

As demonstrated in the quickstart. If a transaction does not already exist, this will initiate a transaction and complete it for you, otherwise the business logic will be integrated into the existing transaction.

RequiresNew

If there is already a transaction running, it will be suspended, the work performed within a new transaction which is completed at exit of the method and then the original transaction resumed.

Mandatory

If there is no transaction running, calling a business method with this annotation will result in an error.

NotSupported

If there is a transaction running, it will be suspended and no transaction will be initiated for this business method.

Supports

This will run the method within a transaction if a transaction exists, alternatively, if there is no transaction running, the method will not be executed within the scope of a transaction.

Never

If the client has a transaction running and does not suspend it but calls a method annotated with Never then an EJB exception will be raised.

Considerations for Use in a Production Environment

H2 Database

This quickstart uses the H2 database included with Red Hat JBoss Enterprise Application Platform 7.4. It is a lightweight, relational example datasource that is used for examples only. It is not robust or scalable, is not supported, and should NOT be used in a production environment.

System Requirements

The application this project produces is designed to be run on Red Hat JBoss Enterprise Application Platform 7.4 or later.

All you need to build this project is Java 8.0 (Java SDK 1.8) or later and Maven 3.3.1 or later. See Configure Maven to Build and Deploy the Quickstarts to make sure you are configured correctly for testing the quickstarts.

Use of the EAP_HOME and QUICKSTART_HOME Variables

In the following instructions, replace EAP_HOME with the actual path to your JBoss EAP installation. The installation path is described in detail here: Use of EAP_HOME and JBOSS_HOME Variables.

When you see the replaceable variable QUICKSTART_HOME, replace it with the path to the root directory of all of the quickstarts.

Start the JBoss EAP Standalone Server

  1. Open a terminal and navigate to the root of the JBoss EAP directory.

  2. Start the JBoss EAP server with the full profile by typing the following command.

    $ EAP_HOME/bin/standalone.sh -c standalone-full.xml
    Note
    		 For Windows, use the EAP_HOME\bin\standalone.bat script.

Build and Deploy the Quickstart

  1. Make sure you start the JBoss EAP server as described above.

  2. Open a terminal and navigate to the root directory of this quickstart.

  3. Type the following command to build the artifacts.

    $ mvn clean package wildfly:deploy

This deploys the cmt/target/cmt.war to the running instance of the server.

You should see a message in the server log indicating that the archive deployed successfully.

Access the Application

The application will be running at the following URL: http://localhost:8080/cmt/

You are presented with a simple form for adding customers to a database.

After a customer is successfully added to the database, a message is produced containing the details of the customer. An example MDB dequeues this message and print the following contents.

Received Message: Created invoice for customer named:  Jack

If an existing customer name is provided, no JMS message is sent. Instead of the above message, a duplicate warning is displayed.

The customer name should match: letter & '-', otherwise an error is given. This is to show that a LogMessage entity is still stored in the database. That is because the logCreateCustomer method in the LogMessageManagerEJB EJB is decorated with the @TransactionAttribute(TransactionAttributeType.REQUIRES_NEW) annotation.

Server Log: Expected Warnings and Errors

You will see the following warnings in the server log. You can ignore these warnings.

HHH000431: Unable to determine H2 database version, certain features may not work

Undeploy the Quickstart

When you are finished testing the quickstart, follow these steps to undeploy the archive.

  1. Make sure you start the JBoss EAP server as described above.

  2. Open a terminal and navigate to the root directory of this quickstart.

  3. Type this command to undeploy the archive:

    $ mvn wildfly:undeploy

Run the Quickstart in Red Hat CodeReady Studio or Eclipse

You can also start the server and deploy the quickstarts or run the Arquillian tests in Red Hat CodeReady Studio or from Eclipse using JBoss tools. For general information about how to import a quickstart, add a JBoss EAP server, and build and deploy a quickstart, see Use Red Hat CodeReady Studio or Eclipse to Run the Quickstarts.

Note
 Within Red Hat CodeReady Studio, make sure you define a server runtime environment that uses the standalone-full.xml configuration file.

Debug the Application

If you want to debug the source code of any library in the project, run the following command to pull the source into your local repository. The IDE should then detect it.

$ mvn dependency:sources

Getting Started with JBoss EAP for OpenShift

This document contains the basic instructions to build and deploy this quickstart to JBoss EAP for OpenShift or JBoss EAP for OpenShift Online.

See Getting Started with JBoss EAP for OpenShift Container Platform for more detailed information about building and running applications on JBoss EAP for OpenShift.

See Getting Started with JBoss EAP for OpenShift Online for more detailed information about building and running applications on JBoss EAP for OpenShift Online.

Prepare OpenShift for Quickstart Deployment

  1. Log in to your OpenShift instance using the oc login command.

  2. Create a new project for the quickstart in OpenShift. You can create a project in OpenShift using the following command.

    $ oc new-project cmt-project

    Before you can import and use the OpenShift image for JBoss EAP for OpenShift , you must configure authentication to the Red Hat Container Registry.

Create an authentication token using a registry service account to configure access to the Red Hat Container Registry. You need not use or store your Red Hat account’s username and password in your OpenShift configuration when you use an authentication token.

Procedure

  1. Follow the instructions on Red Hat Customer Portal to create an authentication token using a registry service account.

  2. Download the YAML file containing the OpenShift secret for the token.

    You can download the YAML file from the OpenShift Secret tab on your token’s Token Information page.

  3. Create the authentication token secret for your OpenShift project using the YAML file that you downloaded:

    oc create -f 1234567_myserviceaccount-secret.yaml

  4. Configure the secret for your OpenShift project using the following commands, replacing the secret name below with the name of your secret created in the previous step.

    oc secrets link default 1234567-myserviceaccount-pull-secret --for=pull
oc secrets link builder 1234567-myserviceaccount-pull-secret --for=pull
    Additional resources

Import the Latest JBoss EAP for OpenShift Imagestreams and Templates

Important

If you are building and deploying this quickstart on JBoss EAP for OpenShift, you must configure authentication to the Red Hat Container Registry before you import the image streams and templates into your namespace. Getting Started with JBoss EAP for OpenShift Container Platform provides an example of one way to configure authentication to the registry. For additional information, see Red Hat Container Registry Authentication on the Red Hat Customer Portal.

Configuration of authentication to the registry is not necessary if you are building and deploying this quickstart on JBoss EAP for OpenShift Online.
Procedure

  1. Use the following commands to import the latest JDK 8 and JDK 11 image streams and templates for the OpenShift image for JBoss EAP for OpenShift, into your OpenShift project’s namespace.

    1. Import JDK 8 image streams:

      oc replace --force -f https://raw.githubusercontent.com/jboss-container-images/jboss-eap-openshift-templates/eap74/eap74-openjdk8-image-stream.json

      This command imports the following imagestreams:

      • The JDK 8 builder imagestream: jboss-eap74-openjdk8-openshift

      • The JDK 8 runtime imagestream: jboss-eap74-openjdk8-runtime-openshift

    2. Import JDK 11 image stream:

      oc replace --force -f https://raw.githubusercontent.com/jboss-container-images/jboss-eap-openshift-templates/eap74/eap74-openjdk11-image-stream.json

      This command imports the following imagestreams:

      • The JDK 11 builder imagestream: jboss-eap74-openjdk11-openshift

      • The JDK 11 runtime imagestream: jboss-eap74-openjdk11-runtime-openshift

    3. Import the JDK 8 and JDK 11 templates:

      for resource in \
  eap74-amq-persistent-s2i.json \
  eap74-amq-s2i.json \
  eap74-basic-s2i.json \
  eap74-https-s2i.json \
  eap74-sso-s2i.json \
  eap74-starter-s2i.json \
  eap74-third-party-db-s2i.json \
  eap74-tx-recovery-s2i.json
do
  oc replace --force -f \
https://raw.githubusercontent.com/jboss-container-images/jboss-eap-openshift-templates/eap74/templates/${resource}
done
Note

The JBoss EAP image streams and templates imported using the above command are only available within that OpenShift project.

If you have administrative access to the general openshift namespace and want the image streams and templates to be accessible by all projects, add -n openshift to the oc replace line of the command. For example:

...
oc replace -n openshift --force -f \
...

Deploy the JBoss EAP Source-to-Image (S2I) Quickstart to OpenShift

Procedure

  1. Create a new OpenShift application using the JBoss EAP for OpenShift image and the quickstart’s source code. Use the following command to use the eap74-basic-s2i template with the JDK 8 images and the cmt source code on GitHub.

    $ oc new-app --template=eap74-basic-s2i \
 -p EAP_IMAGE_NAME=jboss-eap74-openjdk8-openshift:latest \
 -p EAP_RUNTIME_IMAGE_NAME=jboss-eap74-openjdk8-runtime-openshift:latest \
 -p IMAGE_STREAM_NAMESPACE="cmt-project" \
 -p SOURCE_REPOSITORY_URL="https://github.com/jboss-developer/jboss-eap-quickstarts" \
 -p SOURCE_REPOSITORY_REF="7.4.x" \
 -p ENABLE_GENERATE_DEFAULT_DATASOURCE="true" \
 -p CONTEXT_DIR="cmt"

    • --template The template to use.

    • -p IMAGE_STREAM_NAMESPACE The latest images streams and templates were imported into the project’s namespace, so you must specify the namespace of where to find the image stream. This is usually the OpenShift project’s name.

    • -p SOURCE_REPOSITORY_URL The URL to the repository containing the application source code.

    • -p SOURCE_REPOSITORY_REF The Git repository reference to use for the source code. This can be a Git branch or tag reference.

    • -p ENABLE_GENERATE_DEFAULT_DATASOURCE Enables the default datasource, which is required by this quickstart.

    • -p CONTEXT_DIR The directory within the source repository to build.

    Alternatively, to create the quickstart application using the JDK 11 images enter the following command.

    $ oc new-app --template=eap74-basic-s2i \
 -p EAP_IMAGE_NAME=jboss-eap74-openjdk11-openshift:latest \
 -p EAP_RUNTIME_IMAGE_NAME=jboss-eap74-openjdk11-runtime-openshift:latest \
 -p IMAGE_STREAM_NAMESPACE="cmt-project" \
 -p SOURCE_REPOSITORY_URL="https://github.com/jboss-developer/jboss-eap-quickstarts" \
 -p SOURCE_REPOSITORY_REF="7.4.x" \
 -p ENABLE_GENERATE_DEFAULT_DATASOURCE="true" \
 -p CONTEXT_DIR="cmt"

    • --template The template to use.

    • -p IMAGE_STREAM_NAMESPACE The latest images streams and templates were imported into the project’s namespace, so you must specify the namespace of where to find the image stream. This is usually the OpenShift project’s name.

    • -p SOURCE_REPOSITORY_URL The URL to the repository containing the application source code.

    • -p SOURCE_REPOSITORY_REF The Git repository reference to use for the source code. This can be a Git branch or tag reference.

    • -p ENABLE_GENERATE_DEFAULT_DATASOURCE Enables the default datasource, which is required by this quickstart.

    • -p CONTEXT_DIR The directory within the source repository to build.

    Note
    		 A template can specify default values for many template parameters, and you might have to override some, or all, of the defaults. To see template information, including a list of parameters and any default values, use the command oc describe template TEMPLATE_NAME.
    Tip
    		 It is possible to trim down the JBoss EAP for OpenShift image that will be used to run this quickstart. To do so, please add the -p GALLEON_PROVISION_LAYERS=<galleon layers> argument when creating the new application. Please refer to the JBoss EAP documentation for the list of supported galleon layers.

  2. Retrieve the name of the build configuration.

    $ oc get bc -o name

  3. Use the name of the build configurations from the previous step to view the Maven progress of the builds.

    $ oc logs -f bc/${APPLICATION_NAME}-build-artifacts

…
Push successful
$ oc logs -f bc/${APPLICATION_NAME}
…
Push successful

    For example, for the previously created application, the following command shows the progress of the Maven builds.

    $ oc logs -f bc/eap74-basic-app-build-artifacts

…
Push successful
$ oc logs -f bc/eap74-basic-app
…
Push successful

OpenShift Post Deployment Tasks

Depending on your application, you might need to complete some tasks after your OpenShift application has been built and deployed.

Examples of post-deployment tasks include the following:

  • Exposing a service so that the application is viewable from outside of OpenShift.

  • Scaling your application to a specific number of replicas.

Procedure

  1. Get the service name of your application using the following command.

    $ oc get service

  2. Optional: Expose the main service as a route so you can access your application from outside of OpenShift. For example, for the previously created application, use the following command to expose the required service and port.

    Note

    If you used a template to create the application, the route might already exist. If it does, continue on to the next step.

    		 
    $ oc expose service/eap74-basic-app --port=8080

  3. Get the URL of the route.

    $ oc get route

  4. Access the application in your web browser using the URL. The URL is the value of the HOST/PORT field from previous command’s output.

    Note

    For example, to interact with this quickstart , the root of its application URLs should be https://HOST_PORT_Value/.

  5. Optionally, you can scale up the application instance by running the following command. This command increases the number of replicas to 3.

    $ oc scale deploymentconfig DEPLOYMENTCONFIG_NAME --replicas=3

    For example, for this` quickstart, use the following command to scale up the application.

    $ oc scale deploymentconfig/eap74-basic-app --replicas=3