Embedded Jetty server truncates responses

06 August 2019

Jetty server has lot of configuration options. One of them is OutputBufferSize

HttpConfiguration httpConfig = new HttpConfiguration();
httpConfig.setOutputBufferSize(1024);

If this property set to value less than your respopnse - jetty just will truncate last one.

Comments

WFLYEJB0054: Failed to marshal EJB parameters

05 August 2019

Usually error WFLYEJB0054: Failed to marshal EJB parameters can be throw by next reason:

Your data transfer object does not implement Serializable
Your transfered object does not exist in destination module classpath (for example, if you are using DTO without strong typing)

Also, you can catch this error with absolutely unexpected scenario and unclear stacktrace when your EJB throws some unchecked exception with stacktrace that has objects from points above.

Comments

SQL trick. Insert if not exists

24 July 2019

Next SQL trick allows you perform conditional INSERT with your query.

For example, lets do insert if record not exists yet:

SQL:

INSERT INTO my_table (id, name)  
    SELECT 1, 'name' FROM dual  WHERE NOT EXISTS (SELECT 1 FROM my_table WHERE ID = 1);

Comments

JMS Duplicate Message Detection with Wildfly

19 July 2019

To support JMS specification Wildfly uses Apache ActiveMQ Artemis over active-mq subsystem. Last one provides mechanism to filtering out duplicate messages without application code changes.

To enable duplicate message detection you just need to set a special property on the message to a unique value

message.setStringProperty("_AMQ_DUPL_ID", uniqueId);

So, lets see how it works on practice and create simple Message Driven Bean to consume messages:

@JMSDestinationDefinition(
        name = DuplicateJMSTestBean.DUPLICATE_QUEUE,
        interfaceName = "javax.jms.Queue"
)
@MessageDriven(activationConfig = {
    @ActivationConfigProperty(propertyName = "destinationLookup", propertyValue = DuplicateJMSTestBean.DUPLICATE_QUEUE),
    @ActivationConfigProperty(propertyName = "destinationType", propertyValue = "javax.jms.Queue")
})
@TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED)
public class DuplicateJMSTestBean implements MessageListener {

    public final static String DUPLICATE_QUEUE = "java:global/jms/duplicateTestQueue";

    @Override
    public void onMessage(Message msg) {
        System.out.println("Got new message.");
        MessageStorage.messages.add(msg);
        try {
            Thread.sleep(5_000l);
        } catch(Exception ignore) {}
        System.out.println("Message  successfully processed");
    }
}

And simple JAX-RS endpoint to produce messages

@Path("/")
@Stateless
@TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED)
public class DuplicateTestEndpoint {

    @Inject
    private JMSContext context;
    @Resource(lookup = DuplicateJMSTestBean.DUPLICATE_QUEUE)
    private Queue queue;

    @GET
    @Path("/sendmessage")
    public Response sendMessage(@QueryParam("duplicate-id") String duplicateId) {
        try {
            ObjectMessage message = context.createObjectMessage();
            if (duplicateId == null) {
                context.createProducer().send(queue, message);
            } else {
                message.setStringProperty("_AMQ_DUPL_ID", duplicateId);
                context.createProducer().send(queue, message);
            }
            return Response.ok().entity("Message was sent.  Recieved " + MessageStorage.messages.size() + " messagges: " + MessageStorage.messages).build();
        } catch (Throwable e) {
            return Response.ok().entity("Error: " + e).build();
        }
    }
}

Now in case we send message with the same _AMQ_DUPL_ID without transaction by http://127.0.0.1:8080/jms-examples/sendmessage?duplicate-id=myuniqueid we will get in logs:

WARN [org.apache.activemq.artemis.core.server] (Thread-448 (ActiveMQ-server-org.apache.activemq.artemis.core.server.impl.ActiveMQServerImpl$5@e47887a)) AMQ222059: Duplicate message detected - message will not be routed. Message information:
CoreMessage[messageID=1505,durable=true,userID=3d27afde-a9fa-11e9-af5d-0242e352ec80,priority=4, timestamp=Fri Jul 19 10:53:04 EEST 2019,expiration=0, durable=true, address=jms.queue.jms-examples_jms-examples_jms-examples_java:global/jms/duplicateTestQueue,size=416,properties=TypedProperties[__AMQ_CID=38587489-a9fa-11e9-af5d-0242e352ec80,_AMQ_DUPL_ID=myuniqueid,_AMQ_ROUTING_TYPE=1]]@145077408

and message will NOT consume by consumer. In case you send message in transaction - you will get Exception on commit.

Keep in mind, that to store IDs activemq uses circular fixed size cache

/subsystem=messaging-activemq/server=default:read-attribute(name=id-cache-size)
{
    "outcome" => "success",
    "result" => 20000
}

so, this value should be big enough to avoid rewriting. Also, you can configure persist cache or not (by default: true)

/subsystem=messaging-activemq/server=default:write-attribute(name=persist-id-cache,value=false)

Source code available on GitHub

Comments

Jenkins. Nice to have plugins

05 July 2019

Jenkins is leading open source automation tool that provides lot of plugins to make your CI better. Below is few of them that, on my opinion, can be helpful for any project.

1. Build Monitor Plugin - provides a highly visible view of the status of selected Jenkins jobs;

Build Monitor Plugin

2. Git Parameter Plugin - adds ability to choose branches, tags or revisions from git repository configured in project;

Git Parameter Plugin

3. HTML Publisher Plugin - publish the html reports that your build generates to the job and build pages;

Git Parameter Plugin

Comments