how to use clustered map

[Mumuney Abdlquadri]

Hi all,

Please I am trying to retrieve a like below but none of the System.out.println() is being called.

Is there a particular section I need to put code.

SharedData sharedData = vertx.sharedData();

sharedData.getClusterWideMap("ng.pending", (AsyncResult<AsyncMap<String, String>> e) -> {

           if (e.succeeded()) {

                pendingAuthMaps = e.result();

                

                System.out.println("cluseter wide map gotten");

            } else {

                System.out.println("cluseter wide map NOT gotten");

              

            }

        });

Regards.

[mathias]

https://vertx.ci.cloudbees.com/view/vert.x-3/job/vert.x3-website/ws/target/site/docs/vertx-core/java/index.html
I read the docs above but I couldn't get it working either :-(

My setup for a cluster currently consists of three steps:
1. Add dependency to vertx-hazlecast (version 3.0.0-milestone2) in pom.xml
2. Set the system property right at the beginning of my main method:

    System.setProperty("vertx.cluster.managerClass", HazelcastClusterManager.class.getName())

3. Start vertx in cluster mode:

        VertxOptions options = new VertxOptions();
        options.setHAEnabled(true);
        Vertx.clusteredVertx(options, vertxRes -> {
            if (vertxRes.succeeded()) {
                Vertx vertx = vertxRes.result();
                startup(vertx);
            } else {
                logger.error("Failed: " + vertxRes.cause());
            }
        });

But these steps seem to be missing something, because I get the following exception when accessing the clustered map as described above by Mumuney:

java.lang.IllegalStateException: Can't get cluster wide map if not clustered
    at io.vertx.core.shareddata.impl.SharedDataImpl.getClusterWideMap(SharedDataImpl.java:60)

How to solve this exception?

[Mumuney Abdlquadri]

Apparently you have to wait for the Clustered Vertx instance to be up. before trying to get the shared data..

VertxOptions vertxOptions = new VertxOptions().setClustered(true);

        Vertx.clusteredVertx(vertxOptions, (AsyncResult<Vertx> result) -> {

            if (result.succeeded()) {

                clusteredVertx = result.result();

                setUpEventBusMessageHandlers(clusteredVertx.eventBus());

                System.out.println("Event Bus clustered : " + clusteredVertx.eventBus());

                                                                                             /* delibrate indentation*/ getSharedData(); // this is what solved my issue

            } else {

                System.out.println("Event Bus Clustering Failed: " + result.cause());

            }

        });

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[Mumuney Abdlquadri]

also make sure you are using the exact same clusteredVertx instance.

[Tim Fox]

Just as a general note - when in doubt about how to use this things it's often useful to look at the test suite where we have working examples:

https://github.com/eclipse/vert.x/blob/master/src/test/java/io/vertx/test/core/VertxTestBase.java#L113

You need to set clustered to true.

[Mumuney Abdlquadri]

Thanks Tim,

In addition I have learnt to always start a new project and try to recreate the issue, I almost always find a solution.

But Tim like I said in another thread if a user is calling Vertx.clusteredVertx(), they expect to get a clustered vertx instance. so setting clustered true sounds redundant. I understand that is the API and probably there was a reason for it.

Regards.

[Marco Ellwanger]

Hi Tim,

Any reason there are no iterator functions provided within the vertx AsyncMap interface although the Hazelcast IMap interface does provide them? We are keeping track of all verticle deployments within a cluster with some additional info (vertx.deploymentIDs() only returns the local vertx instance deployments IIRC) and while deploymentIDs make good map keys, there's currently no clean way to iterate over a (detached) snasphot of an asyncMap (aside from reflection plus casting to the underlying hazelcast IMap).

cheers