Getting started with littlegridΒΆ

This getting started will only take about 1-2 minutes to complete, but by the end you would have run an entire Coherence cluster in a single JVM and performed operations against a cache.

Before getting started, you’ll need to download Coherence and follow Getting littlegrid (littlegrid is Maven and Gradle friendly). Once you’ve got Coherence and littlegrid, you’re ready to create a simple JUnit test - you can use your favourite IDE or even Notepad if you want :-).

Note

Here’s a JUnit example - note the use of @BeforeClass and @AfterClass, this enables the cluster to be re-used across the tests in the class.

import com.tangosol.net.CacheFactory;
import com.tangosol.net.NamedCache;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;
import org.littlegrid.ClusterMemberGroup;
import org.littlegrid.ClusterMemberGroupUtils;

import static org.junit.Assert.assertEquals;

/**
 * Simple integration test example.
 */
public final class SimpleStorageEnabledIntegrationTest {
    private static ClusterMemberGroup memberGroup;

    @BeforeClass
    public static void beforeTests() {
        memberGroup = ClusterMemberGroupUtils.newBuilder()
                .setStorageEnabledCount(2)
                .buildAndConfigureForStorageDisabledClient();
    }

    @AfterClass
    public static void afterTests() {
        ClusterMemberGroupUtils.shutdownCacheFactoryThenClusterMemberGroups(memberGroup);
    }

    @Test
    public void simpleExample() {
        final NamedCache cache = CacheFactory.getCache("test");
        cache.put("key", "Hello World");

        assertEquals(1, cache.size());
    }
}

The above simple test actually does quite a bit with just a couple of lines of code, firstly it starts two cache servers (storage-enabled cluster members) and then the test itself joins the cluster as a storage-disabled client where it then performs simple actions against the test cache.

Note

Notice how the littlegrid specific code is both fluent (i.e. simple to understand) and also there isn’t much of it - littlegrid is fairly non-intrusive to introduce into an existing code-base.

You should see some output similar to the below:

Sep 10, 2014 6:53:50 PM org.littlegrid.impl.DefaultClusterMemberGroupBuilder <init>
INFO: ___ littlegrid 2.16-SNAPSHOT (http://www.littlegrid.org) - initialised.  Builder values: {default file=50, override file=3, 'littlegrid_builder_' environment variables=0, 'LITTLEGRID_BUILDER_' environment variables=0, 'littlegrid.builder.' system properties=2}.  Builder to Coherence system property mapping values: {default file=41, override file=0} ___
Sep 10, 2014 6:53:50 PM org.littlegrid.impl.DefaultClusterMemberGroupBuilder buildClusterMembers
INFO: ___ littlegrid 2.16-SNAPSHOT starting - Storage-enabled: 2, Extend proxy: 0, Storage-enabled proxy: 0, JMX: 0, Custom configured: 0 ___
Sep 10, 2014 6:53:50 PM org.littlegrid.impl.DefaultConfigurer getSystemPropertiesForTcmpClusterMember
WARNING: Fast-start join timeout specified.  Note: the fast-start Coherence override file will now be configured to be used
Sep 10, 2014 6:53:50 PM org.littlegrid.impl.DefaultClusterMemberGroup outputStartAllMessages
INFO: System properties to be set.: {com.sun.management.jmxremote=false, littlegrid.join.timeout.milliseconds=100, tangosol.coherence.cacheconfig=coherence/littlegrid-test-cache-config.xml, tangosol.coherence.cluster=littlegridCluster, tangosol.coherence.distributed.localstorage=true, tangosol.coherence.extend.address=127.0.0.1, tangosol.coherence.localhost=127.0.0.1, tangosol.coherence.localport=40100, tangosol.coherence.log=stdout, tangosol.coherence.log.level=3, tangosol.coherence.machine=DefaultMachine, tangosol.coherence.management=none, tangosol.coherence.management.remote=true, tangosol.coherence.override=littlegrid/littlegrid-fast-start-coherence-override.xml, tangosol.coherence.rack=DefaultRack, tangosol.coherence.role=DedicatedStorageEnabledMember, tangosol.coherence.site=DefaultSite, tangosol.coherence.tcmp.enabled=true, tangosol.coherence.ttl=0, tangosol.coherence.wka=127.0.0.1, tangosol.coherence.wka.port=40100, tangosol.pof.enabled=false}
Sep 10, 2014 6:53:50 PM org.littlegrid.impl.DefaultClusterMemberGroup outputMemoryMessage
INFO: Max memory: 736MB, current: 736MB, free memory: 720MB
2014-09-10 18:53:50.644/0.803 Oracle Coherence 12.1.3.0.0 <Info> (thread=pool-1-thread-1, member=n/a): Loaded operational configuration from "jar:file:/home/jhall/.m2/repository/com/oracle/coherence/coherence/12.1.3-0-0/coherence-12.1.3-0-0.jar!/tangosol-coherence.xml"
2014-09-10 18:53:50.647/0.806 Oracle Coherence 12.1.3.0.0 <Info> (thread=pool-1-thread-1, member=n/a): Loaded operational overrides from "file:/home/jhall/littlegrid/littlegrid-coherence-testsupport/target/classes/littlegrid/littlegrid-fast-start-coherence-override.xml"

Oracle Coherence Version 12.1.3.0.0 Build 52031
 Grid Edition: Development mode
Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.

2014-09-10 18:53:50.970/1.129 Oracle Coherence GE 12.1.3.0.0 <Info> (thread=pool-1-thread-1, member=n/a): Loaded cache configuration from "file:/home/jhall/littlegrid/littlegrid-coherence-testsupport/target/test-classes/coherence/littlegrid-test-cache-config.xml"
2014-09-10 18:53:51.550/1.709 Oracle Coherence GE 12.1.3.0.0 <Info> (thread=pool-1-thread-1, member=n/a): Created cache factory com.tangosol.net.ExtensibleConfigurableCacheFactory
2014-09-10 18:53:52.208/2.367 Oracle Coherence GE 12.1.3.0.0 <Warning> (thread=pool-1-thread-1, member=n/a): Local address "127.0.0.1" is a loopback address; this cluster node will not connect to nodes located on different machines
2014-09-10 18:53:52.250/2.409 Oracle Coherence GE 12.1.3.0.0 <Warning> (thread=pool-1-thread-1, member=n/a): UnicastUdpSocket failed to set send buffer size to 8 packets (512KB); actual size is 40%, 3 packets (208KB). Consult your OS documentation regarding increasing the maximum socket buffer size. Proceeding with the actual value may cause sub-optimal performance.
2014-09-10 18:53:52.250/2.409 Oracle Coherence GE 12.1.3.0.0 <Warning> (thread=pool-1-thread-1, member=n/a): UnicastUdpSocket failed to set receive buffer size to 64 packets (4MB); actual size is 5%, 3 packets (208KB). Consult your OS documentation regarding increasing the maximum socket buffer size. Proceeding with the actual value may cause sub-optimal performance.
2014-09-10 18:53:52.251/2.410 Oracle Coherence GE 12.1.3.0.0 <Warning> (thread=pool-1-thread-1, member=n/a): PreferredUnicastUdpSocket failed to set receive buffer size to 128 packets (8MB); actual size is 2%, 3 packets (208KB). Consult your OS documentation regarding increasing the maximum socket buffer size. Proceeding with the actual value may cause sub-optimal performance.
2014-09-10 18:53:52.527/2.686 Oracle Coherence GE 12.1.3.0.0 <Info> (thread=Cluster, member=n/a): Created a new cluster "littlegridCluster" with Member(Id=1, Timestamp=2014-09-10 18:53:52.302, Address=127.0.0.1:40100, MachineId=30438, Location=site:DefaultSite,rack:DefaultRack,machine:DefaultMachine,process:32042, Role=DedicatedStorageEnabledMember, Edition=Grid Edition, Mode=Development, CpuCount=4, SocketCount=2)
2014-09-10 18:53:52.529/2.688 Oracle Coherence GE 12.1.3.0.0 <Info> (thread=pool-1-thread-1, member=n/a): Started cluster Name=littlegridCluster

WellKnownAddressList(Size=1,
  WKA{Address=127.0.0.1, Port=40100}
  )

MasterMemberSet(
  ThisMember=Member(Id=1, Timestamp=2014-09-10 18:53:52.302, Address=127.0.0.1:40100, MachineId=30438, Location=site:DefaultSite,rack:DefaultRack,machine:DefaultMachine,process:32042, Role=DedicatedStorageEnabledMember)
  OldestMember=Member(Id=1, Timestamp=2014-09-10 18:53:52.302, Address=127.0.0.1:40100, MachineId=30438, Location=site:DefaultSite,rack:DefaultRack,machine:DefaultMachine,process:32042, Role=DedicatedStorageEnabledMember)
  ActualMemberSet=MemberSet(Size=1
    Member(Id=1, Timestamp=2014-09-10 18:53:52.302, Address=127.0.0.1:40100, MachineId=30438, Location=site:DefaultSite,rack:DefaultRack,machine:DefaultMachine,process:32042, Role=DedicatedStorageEnabledMember)
    )
  MemberId|ServiceVersion|ServiceJoined|MemberState
    1|12.1.3|2014-09-10 18:53:52.302|JOINED
  RecycleMillis=1200000
  RecycleSet=MemberSet(Size=0
    )
  )

TcpRing{Connections=[]}
IpMonitor{Addresses=0, Timeout=15s}

...
Sep 10, 2014 6:53:55 PM org.littlegrid.impl.DefaultClusterMemberGroupBuilder buildClusterMembers
INFO: ___ Group of 2 cluster member(s) started in 5177ms, member Ids are: [1, 2] ___
Sep 10, 2014 6:53:55 PM org.littlegrid.impl.DefaultConfigurer getSystemPropertiesForTcmpClusterMember
WARNING: Fast-start join timeout specified.  Note: the fast-start Coherence override file will now be configured to be used
Sep 10, 2014 6:53:55 PM org.littlegrid.impl.DefaultConfigurer configureFor
INFO: System properties set for client/member: {com.sun.management.jmxremote=false, littlegrid.join.timeout.milliseconds=100, tangosol.coherence.cacheconfig=coherence/littlegrid-test-cache-config.xml, tangosol.coherence.cluster=littlegridCluster, tangosol.coherence.distributed.localstorage=false, tangosol.coherence.extend.address=127.0.0.1, tangosol.coherence.extend.enabled=false, tangosol.coherence.localhost=127.0.0.1, tangosol.coherence.localport=40100, tangosol.coherence.log=stdout, tangosol.coherence.log.level=3, tangosol.coherence.machine=DefaultMachine, tangosol.coherence.management=none, tangosol.coherence.management.remote=true, tangosol.coherence.override=littlegrid/littlegrid-fast-start-coherence-override.xml, tangosol.coherence.rack=DefaultRack, tangosol.coherence.role=StorageDisabledClient, tangosol.coherence.site=DefaultSite, tangosol.coherence.tcmp.enabled=true, tangosol.coherence.ttl=0, tangosol.coherence.wka=127.0.0.1, tangosol.coherence.wka.port=40100, tangosol.pof.enabled=false}
Sep 10, 2014 6:53:57 PM org.littlegrid.ClusterMemberGroupUtils shutdownCacheFactoryThenClusterMemberGroups
INFO: About to shutdown cache factory
Sep 10, 2014 6:53:58 PM org.littlegrid.impl.DefaultClusterMemberGroup shutdownAll
INFO: Restoring system properties back to their original state before member group started
2014-09-10 18:53:58.135/8.294 Oracle Coherence GE 12.1.3.0.0 <Info> (thread=DistributedCache, member=n/a): Remains to transfer before shutting down: 129 primary partitions, 128 backup partitions
2014-09-10 18:53:58.264/8.423 Oracle Coherence GE 12.1.3.0.0 <Info> (thread=DistributedCache, member=n/a): Remains to transfer before shutting down: 0 primary partitions, 128 backup partitions
Sep 10, 2014 6:54:00 PM org.littlegrid.impl.DefaultClusterMemberGroup shutdownAll
INFO: ___ Group of 2 cluster member(s) shutdown in 2392ms ___

Notice how littlegrid has done the following:

  • Ensured that WKA (Well Known Addresses) are being used and that the network traffic is restricted to this machine - this prevents accidental clustering.
  • Given the members sensible rolenames, such as DedicatedStorageEnabledMember.
  • Used different port numbers to avoid clustering with vanilla Coherence instances you might have already running.

Note

littlegrid has ways of making tests start faster and re-using an existing cluster across tests for even faster testing.