Table of Contents - Apache ActiveMQWritten in Java. Runs on any platform with a Java 8+ runtime, that's everything from Windows desktops to IBM mainframes. Amazing performance. Our

1.1

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

1.10

1.11

1.12

1.13

1.14

1.15

1.16

1.17

1.18

1.19

1.20

1.21

1.22

1.23

1.24

1.25

1.26

1.27

1.28

1.29

1.30

1.31

1.32

1.33

1.34

1.35

1.36

1.37

TableofContentsIntroduction

LegalNotice

Preface

ProjectInfo

Versions

MessagingConcepts

Architecture

UsingtheServer

Upgrading

AddressModel

ProtocolsandInteroperability

AMQP

MQTT

STOMP

OpenWire

Core

MappingJMSConceptstotheCoreAPI

UsingJMS

TheClientClasspath

Examples

RoutingMessagesWithWildCards

WildcardSyntax

FilterExpressions

Persistence

ConfiguringTransports

ConfigurationReload

DetectingDeadConnections

DetectingSlowConsumers

AvoidingNetworkIsolation

DetectingBrokerIssues(CriticalAnalysis)

ResourceManagerConfiguration

FlowControl

Guaranteesofsendsandcommits

MessageRedeliveryandUndeliveredMessages

MessageExpiry

LargeMessages

Paging

1

1.39

1.40

1.41

1.42

1.43

1.44

1.45

1.46

1.47

1.48

1.49

1.50

1.51

1.52

1.53

1.54

1.55

1.56

1.57

1.58

1.59

1.60

1.60.1

1.60.2

1.61

1.62

1.63

1.64

1.65

1.66

1.67

1.68

1.69

1.70

1.71

1.72

1.73

1.74

1.75

1.38ScheduledMessages

Last-ValueQueues

RingQueues

RetroactiveAddresses

ExclusiveQueues

MessageGrouping

ConsumerPriority

ExtraAcknowledgeModes

Management

ManagementConsole

Metrics

Security

MaskingPasswords

BrokerPlugins

ResourceLimits

TheJMSBridge

ClientReconnectionandSessionReattachment

DivertingandSplittingMessageFlows

CoreBridges

Transformers

DuplicateMessageDetection

Clusters

Federation

AddressFederation

QueueFederation

HighAvailabilityandFailover

GracefulServerShutdown

LibaioNativeLibraries

Threadmanagement

EmbeddedWebServer

Logging

RESTInterface

EmbeddingtheBroker

ApacheKaraf

ApacheTomcat

SpringIntegration

CDIIntegration

InterceptingOperations

DataTools

MavenPlugin

2

1.77

1.78

1.76UnitTesting

TroubleshootingandPerformanceTuning

ConfigurationReference

3

ApacheActiveMQArtemisUserManualTheUsermanualisanindepthmanualonallaspectsofApacheActiveMQArtemis

Introduction

4

LegalNoticeLicensedtotheApacheSoftwareFoundation(ASF)underoneormorecontributorlicenseagreements.SeetheNOTICEfiledistributedwiththisworkforadditionalinformationregardingcopyrightownership.TheASFlicensesthisfiletoYouundertheApacheLicense,Version2.0(the"License");youmaynotusethisfileexceptincompliancewiththeLicense.YoumayobtainacopyoftheLicenseat

http://www.apache.org/licenses/LICENSE-2.0

Unlessrequiredbyapplicablelaworagreedtoinwriting,softwaredistributedundertheLicenseisdistributedonan"ASIS"BASIS,WITHOUTWARRANTIESORCONDITIONSOFANYKIND,eitherexpressorimplied.SeetheLicenseforthespecificlanguagegoverningpermissionsandlimitationsundertheLicense.

LegalNotice

5

http://www.apache.org/licenses/LICENSE-2.0

PrefaceWhatisApacheActiveMQArtemis?

ApacheActiveMQArtemisisanopensourceprojecttobuildamulti-protocol,embeddable,veryhighperformance,clustered,asynchronousmessagingsystem.

ApacheActiveMQArtemisisanexampleofMessageOrientedMiddleware(MoM).ForadescriptionofMoMsandothermessagingconceptspleaseseetheMessagingConcepts.

WhyuseApacheActiveMQArtemis?Herearejustafewofthereasons:

100%opensourcesoftware.ApacheActiveMQArtemisislicensedusingtheApacheSoftwareLicensev2.0tominimisebarrierstoadoption.

ApacheActiveMQArtemisisdesignedwithusabilityinmind.

WritteninJava.RunsonanyplatformwithaJava8+runtime,that'severythingfromWindowsdesktopstoIBMmainframes.

Amazingperformance.Ourground-breakinghighperformancejournalprovidespersistentmessagingperformanceatratesnormallyseenfornon-persistentmessaging,ournon-persistentmessagingperformancerockstheboattoo.

Fullfeatureset.Allthefeaturesyou'dexpectinanyseriousmessagingsystem,andothersyouwon'tfindanywhereelse.

Elegant,clean-cutdesignwithminimalthirdpartydependencies.RunActiveMQArtemisstand-alone,runitinintegratedinyourfavouriteJavaEEapplicationserver,orrunitembeddedinsideyourownproduct.It'suptoyou.

Seamlesshighavailability.WeprovideaHAsolutionwithautomaticclientfailoversoyoucanguaranteezeromessagelossorduplicationineventofserverfailure.

Hugelyflexibleclustering.Createclustersofserversthatknowhowtoloadbalancemessages.Linkgeographicallydistributedclustersoverunreliableconnectionstoformaglobalnetwork.Configureroutingofmessagesinahighlyflexibleway.

Preface

6

ProjectInformationTheofficialApacheActiveMQArtemisprojectpageishttp://activemq.apache.org/artemis/.

SoftwareDownload

ThesoftwarecanbedownloadfromtheDownloadpage:http://activemq.apache.org/artemis/download.html

ProjectInformation

Ifyouhaveanyuserquestionspleaseuseouruserforum

Ifyouhavedevelopmentrelatedquestions,pleaseuseourdeveloperforum

PopinandchattousinourIRCchannel

ApacheActiveMQArtemisGitrepositoryishttps://github.com/apache/activemq-artemis

Allreleasetagsareavailablefromhttps://github.com/apache/activemq-artemis/releases

Andmanythankstoallourcontributors,botholdandnewwhohelpedcreateApacheActiveMQArtemis.

ProjectInfo

7

http://activemq.apache.org/artemis/http://activemq.apache.org/artemis/download.htmlhttp://activemq.2283324.n4.nabble.com/ActiveMQ-User-f2341805.htmlhttp://activemq.2283324.n4.nabble.com/ActiveMQ-Dev-f2368404.htmlirc://irc.freenode.net:6667/apache-activemqhttps://github.com/apache/activemq-artemishttps://github.com/apache/activemq-artemis/releases

VersionsThischapterprovidesthefollowinginformationforeachrelease:

Alinktothefullreleasenoteswhichincludesallissuesresolvedintherelease.Abrieflistof"highlights"whenapplicable.Ifnecessary,specificstepsrequiredwhenupgradingfromthepreviousversion.

Note:Iftheupgradespansmultipleversionsthenthestepsfromeachversionneedtobefollowedinorder.Note:FollowthegeneralupgradeprocedureoutlinedintheUpgradingtheBrokerchapterinadditiontoanyversion-specificupgradeinstructionsoutlinedhere.

2.11.0

Fullreleasenotes.

Highlights:

Supportretroactiveaddresses.Supportdownstreamfederatedqueuesandaddresses.MakesecuritymanagerconfigurableviaXML.SupportpluggableSSLTrustManagerFactory.Addpluginsupportforfederatedqueues/addresses.Support com.sun.jndi.ldap.read.timeoutinLDAPLoginModule.

2.10.0

Fullreleasenotes.

Thiswasmainlyabug-fixreleasewithanotabledependencychangeimpactingversionupgrade.

Upgradingfrom2.9.0

DuetotheWildFlydependencyupgradethebrokerstartscripts/configurationneedtobeadjustedafterupgrading.

On*nix

Locatethisstatementin bin/artemis:

WILDFLY_COMMON="$ARTEMIS_HOME/lib/wildfly-common-1.5.1.Final.jar"

Thisneedstobereplacedwiththis:


OnWindows

Locatethispartof JAVA_ARGSin etc/artemis.profile.cmdrespectively bin/artemis-service.xml:

%ARTEMIS_HOME%\lib\wildfly-common-1.5.1.Final.jar

Versions

8

https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12346258https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12345602


%ARTEMIS_HOME%\lib\wildfly-common-1.5.2.Final.jar

2.9.0

Fullreleasenotes.

Thiswasalightrelease.Itincludedahandfulofbugfixes,afewimprovements,andonemajornewfeature.

Highlights:

Supportexportingmetrics.

2.8.1

Fullreleasenotes.

Thiswasmainlyabug-fixreleasewithanotabledependencychangeimpactingversionupgrade.

Upgradingfrom2.8.0

DuetothedependencyupgrademadeonARTEMIS-2319thebrokerstartscriptsneedtobeadjustedafterupgrading.

On*nix

Locatethis ifstatementin bin/artemis:

if[-z"$LOG_MANAGER"];then

#thisistheonefoundwhentheserverwascreated

LOG_MANAGER="$ARTEMIS_HOME/lib/jboss-logmanager-2.0.3.Final.jar"

fi

Thisneedstobereplacedwiththisblock:

if[-z"$LOG_MANAGER"];then


LOG_MANAGER="$ARTEMIS_HOME/lib/jboss-logmanager-2.1.10.Final.jar"

fi

WILDFLY_COMMON=`ls$ARTEMIS_HOME/lib/wildfly-common*jar2>/dev/null`

if[-z"$WILDFLY_COMMON"];then



fi

Noticethatthe jboss-logmanagerversionhaschangedandthereisalsoanew wildfly-commonlibrary.

Notmuchfurtherdownthereisthisline:

-Xbootclasspath/a:"$LOG_MANAGER"\

Thislineshouldbechangedtobe:

-Xbootclasspath/a:"$LOG_MANAGER:$WILDFLY_COMMON"\

Versions

9

https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12345527https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12345432https://issues.apache.org/jira/browse/ARTEMIS-2319

OnWindows

Locatethispartof JAVA_ARGSin etc/artemis.profile.cmdrespectively bin/artemis-service.xml:

-Xbootclasspath/a:%ARTEMIS_HOME%\lib\jboss-logmanager-2.1.10.Final.jar


-Xbootclasspath/a:%ARTEMIS_HOME%\lib\jboss-logmanager-2.1.10.Final.jar;%ARTEMIS_HOME%\lib\wildfly-common-1.5.1.

Final.jar

2.8.0

Fullreleasenotes.

Highlights:

SupportActiveMQ5featureJMSXGroupFirstForConsumer.Clarifyhandshaketimeouterrorwithremoteaddress.SupportduplicatedetectionforAMQPmessagesthesameascore.

2.7.0

Fullreleasenotes.

Highlights:

Supportadvanceddestinationoptionslike consumersBeforeDispatchStartsand timeBeforeDispatchStartsfrom5.x.Addsupportfordelaysbeforedeletingaddressesandqueuesvia auto-delete-queues-delayand auto-delete-addresses-delayAddressSettings.SupportloggingHTTPaccess.AddaCLIcommandtopurgeaqueue.SupportuserandrolemanipulationforPropertiesLoginModuleviamanagementinterfaces.Dockerimages.Auditlogging.Implementingconsumerpriority.SupportFQQNforproducers.Trackroutedandunroutedmessagessenttoanaddress.SupportconnectionpoolinginLDAPLoginModule.Supportconfiguringadefaultconsumerwindowsizevia default-consumer-window-sizeAddressSetting.Supportmasking key-store-passwordand trust-store-passwordinmanagement.xml.Support JMSXGroupSeq-1toclose/resetmessagegroupsfrom5.x.AllowconfigurationofRMIregistryport.Supportrouting-typeconfigurationoncorebridge.Moveartemis-nativeasitsownproject,asactivemq-artemis-native.Supportfederatedqueuesandaddresses.

2.6.4Fullreleasenotes.

Versions

10

https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12345169https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12342977https://github.com/apache/activemq-artemis/tree/master/artemis-dockerhttps://github.com/apache/activemq-artemis-nativehttps://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12344010

Thiswasmainlyabug-fixreleasewithafewimprovementsacouplenotablenewfeatures:

Highlights:

Addedtheabilitytosetthetextmessagecontentonthe producerCLIcommand.Supportreloadloggingconfigurationatruntime.


Thiswasmainlyabug-fixreleasewithafewimprovementsbutnosubstantialnewfeatures.

2.6.2

Fullreleasenotes.

Thiswasabug-fixreleasewithnosubstantialnewfeaturesorimprovements.


Thiswasabug-fixreleasewithnosubstantialnewfeaturesorimprovements.

2.6.0

Fullreleasenotes.

Highlights:

Supportregularexpressionsformatchingclientcertificates.Support SASL_EXTERNALforAMQPclients.Newexamplesshowingvirtualtopicmappingandexclusivequeuefeatures.

2.5.0

Fullreleasenotes.

Highlights:

Exclusiveconsumers.EquivalentActiveMQ5.xVirtualTopicnamingabilities.SSLCertificaterevocationlist.Last-valuequeuesupportforOpenWire.Supportmaskedpasswordsinbootstrap.xmandlogin.configConfigurablebrokerpluginimplementationforloggingvariousbrokerevents(i.e. LoggingActiveMQServerPlugin).OptiontouseOpenSSLproviderforNettyviathe sslProviderURLparameter.Enablesplittingofbroker.xmlintomultiplefiles.Enhancedmessagecountandsizemetricsforqueues.

Upgradingfrom2.4.0

Versions

11

https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12343472https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12343404https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12343356https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12342903https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12342127

1. DuetochangesfromARTEMIS-1644any acceptorthatneedstobecompatiblewithHornetQand/orArtemis1.xclientsneedstohave anycastPrefix=jms.queue.;multicastPrefix=jms.topic.inthe acceptorurl.Thisprefixusedtobeconfiguredautomaticallybehindthesceneswhenthebrokerdetectedtheseoldtypesofclients,butthatbrokecertainuse-caseswithnopossiblework-around.SeeARTEMIS-1644formoredetails.

2.4.0

Fullreleasenotes.

Highlights:

JMXconfigurationviaXMLratherthanhavingtousesystempropertiesviacommandlineorstartscript.ConfigurationofmaxframepayloadlengthforSTOMPweb-socket.AbilitytoconfigureHAusingJDBCpersistence.Implementrole-basedaccesscontrolformanagementobjects.

Upgradingfrom2.3.0

1. Create /etc/management.xml.Attheveryleast,thefilemustcontainthis:

ThisconfiguresrolebasedauthorisationforJMX.ReadmoreintheManagementdocumentation.2. Ifconfigured,removetheJolokiawarfilefromthe webelementin /etc/bootstrap.xml:

ThisisnolongerrequiredastheJolokiaRESTinterfaceisnowintegratedintotheconsolewebapplication.

Ifthefollowingisabsentandyoudesiretodeploythewebconsolethenadd:

Note:theJolokiaRESTinterfaceURLwillnowbeat http://:/console/jolokia


Highlights:

Webadminconsole!CriticalAnalysisanddeadlockdetectiononbrokerSupportNettynativekqueueonMac.Last-valuequeueforAMQP

Upgradingfrom2.2.0

1. Ifyoudesiretodeploythewebconsolethenaddthefollowingtothe webelementin/etc/bootstrap.xml:

Versions

12

https://issues.apache.org/jira/browse/ARTEMIS-1644https://issues.apache.org/jira/browse/ARTEMIS-1644https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12341540https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12341247

2.2.0

Fullreleasenotes.

Highlights:

ScheduledmessageswiththeSTOMPprotocol.SupportforJNDIReferenceFactoryandJNDIStorable.Abilitytodeletequeuesandaddresseswhenbroker.xmlchanges.ClientauthenticationviaKerberosTLSCipherSuites(RFC2712).

2.1.0

Fullreleasenotes.

Highlights:

Brokerpluginsupport.SupportNettynativeepollonLinux.Abilitytoconfigurearbitrarysecurityrolemappings.AMQPperformanceimprovements.

2.0.0

Fullreleasenotes.

Highlights:

Hugeupdateinvolvingasignificantrefactoringoftheaddressingmodelyieldingthefollowingbenefits:SimplerandmoreflexibleXMLconfiguration.Supportforadditionalmessaginguse-cases.EliminatesconfusingJMS-specificqueuenamingconventions(i.e."jms.queue."&"jms.topic."prefixes).

PureencodingofmessagessoprotocolslikeAMQPdon'tneedtoconvertmessagesto"core"formatunlessabsolutelynecessary."MAPPED"journaltypeforincreasedperformanceincertainuse-cases.


Highlights:

Bugfixes.


Highlights:

Bugfixes.

Versions

13

https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12340541https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12339963https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12338813https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12340547https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12339947

1.5.4

Fullreleasenotes.

Highlights:

SupportOracle12CforJDBCpersistence.Bugfixes.

1.5.3

Fullreleasenotes.

Highlights:

Support"bytenotation"(e.g."K","KB","Gb",etc.)inbrokerXMLconfiguration.CLIcommandtorecalculatedisksynctimes.Bugfixes.

1.5.2

Fullreleasenotes.

Highlights:

SupportforpagingusingJDBC.Bugfixes.


Highlights:

SupportoutgoingconnectionsforAMQP.Bugfixes.


Highlights:

AMQPperformanceimprovements.JUnitruleimplementationsomessagingresourceslikebrokerscanbeeasilyconfiguredintests.BasicCDIintegration.Storeuser'spasswordinhashformbydefault.


Versions

14

https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12339158https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12339575https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12338833https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12338661https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12338118https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12336052

Highlights:

"Global"limitfordiskusage.DetectandreloadcertainXMLconfigurationchangesatruntime.MQTTinterceptors.Supportadding/deletingqueuesviaCLI.New"browse"securitypermissionforclientswhoonlywishtolookatmessages.OptiontopopulateJMSXUserID."Dualauthentication"supporttoauthenticateSSL-basedandnon-SSL-basedclientsdifferently.

1.3.0

Fullreleasenotes.

Highlights:

BettersupportofOpenWirefeatures(e.g.reconnect,producerflow-control,optimizedacknowledgements)SSLkeystorereloadatruntime.InitialsupportforJDBCpersistence.Supportscheduledmessagesonlast-valuequeue.

1.2.0

Fullreleasenotes.

Highlights:

ImprovementsaroundperformanceOSGisupport.Supportfunctionalityequivalenttoall5.xJAASloginmodulesincluding:

PropertiesfileLDAPSSLcertificate"Guest"

1.1.0

Fullreleasenotes.

Highlights:

MQTTsupport.TheexamplesnowusetheCLIprogrammaticallytocreate,start,stop,etc.serversreflectingrealcasesusedinproduction.CLIimprovements.Therearenewtoolstocompactthejournalandadditionalimprovementstotheuserexperience.Configurableresourcelimits.Abilitytodisableserver-sidemessageload-balancing.


Highlights:

Versions

15

https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12328978https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12333274https://issues.apache.org/jira/secure/ReleaseNote.jspa?version=12332642&projectId=12315920https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12315920&version=12328953http://mail-archives.apache.org/mod_mbox/activemq-dev/201407.mbox/%3cCAKF+bsovr7Hvn-rMYkb3pF6hoGjx7nuJWzT_Nh8MyC4usRBX9A@mail.gmail.com%3e

Firstreleaseofthedonatedcode-baseasActiveMQArtemis!LotsoffeaturesforparitywithActiveMQ5.xincluding:

OpenWiresupportAMQP1.0supportURLbasedconnectionsAuto-createaddresses/queuesJolokiaintegration

Versions

16

MessagingConceptsApacheActiveMQArtemisisanasynchronousmessagingsystem,anexampleofMessageOrientedMiddleware,we'lljustcallthemmessagingsystemsintheremainderofthisbook.

We'llfirstpresentabriefoverviewofwhatkindofthingsmessagingsystemsdo,wherethey'reusefulandthekindofconceptsyou'llhearaboutinthemessagingworld.

Ifyou'realreadyfamiliarwithwhatamessagingsystemisandwhatit'scapableof,thenyoucanskipthischapter.

GeneralConceptsMessagingsystemsallowyoutolooselycoupleheterogeneoussystemstogether,whilsttypicallyprovidingreliability,transactionsandmanyotherfeatures.

UnlikesystemsbasedonaRemoteProcedureCall(RPC)pattern,messagingsystemsprimarilyuseanasynchronousmessagepassingpatternwithnotightrelationshipbetweenrequestsandresponses.Mostmessagingsystemsalsosupportarequest-responsemodebutthisisnotaprimaryfeatureofmessagingsystems.

Designingsystemstobeasynchronousfromend-to-endallowsyoutoreallytakeadvantageofyourhardwareresources,minimizingtheamountofthreadsblockingonIOoperations,andtouseyournetworkbandwidthtoitsfullcapacity.WithanRPCapproachyouhavetowaitforaresponseforeachrequestyoumakesoarelimitedbythenetworkroundtriptime,orlatencyofyournetwork.Withanasynchronoussystemyoucanpipelineflowsofmessagesindifferentdirections,soarelimitedbythenetworkbandwidthnotthelatency.Thistypicallyallowsyoutocreatemuchhigherperformanceapplications.

Messagingsystemsdecouplethesendersofmessagesfromtheconsumersofmessages.Thesendersandconsumersofmessagesarecompletelyindependentandknownothingofeachother.Thisallowsyoutocreateflexible,looselycoupledsystems.

Often,largeenterprisesuseamessagingsystemtoimplementamessagebuswhichlooselycouplesheterogeneoussystemstogether.MessagebusesoftenformthecoreofanEnterpriseServiceBus.(ESB).Usingamessagebustode-coupledisparatesystemscanallowthesystemtogrowandadaptmoreeasily.Italsoallowsmoreflexibilitytoaddnewsystemsorretireoldonessincetheydon'thavebrittledependenciesoneachother.

Messagingstyles

Messagingsystemsnormallysupporttwomainstylesofasynchronousmessaging:messagequeuemessaging(alsoknownaspoint-to-pointmessaging)andpublishsubscribemessaging.We'llsummarisethembrieflyhere:

Point-to-Point

Withthistypeofmessagingyousendamessagetoaqueue.Themessageisthentypicallypersistedtoprovideaguaranteeofdelivery,thensometimelaterthemessagingsystemdeliversthemessagetoaconsumer.Theconsumerthenprocessesthemessageandwhenitisdone,itacknowledgesthemessage.Oncethemessageisacknowledgeditdisappearsfromthequeueandisnotavailabletobedeliveredagain.Ifthesystemcrashesbeforethemessagingserverreceivesanacknowledgementfromtheconsumer,thenonrecovery,themessagewillbeavailabletobedeliveredtoaconsumeragain.

Withpoint-to-pointmessaging,therecanbemanyconsumersonthequeuebutaparticularmessagewillonlyeverbeconsumedbyamaximumofoneofthem.Senders(alsoknownasproducers)tothequeuearecompletelydecoupledfromreceivers(alsoknownasconsumers)ofthequeue-theydonotknowofeachother'sexistence.

Aclassicexampleofpointtopointmessagingwouldbeanorderqueueinacompany'sbookorderingsystem.Eachorderisrepresentedasamessagewhichissenttotheorderqueue.Let'simaginetherearemanyfrontendorderingsystemswhichsend

MessagingConcepts

17

https://en.wikipedia.org/wiki/Message-oriented_middlewarehttps://en.wikipedia.org/wiki/Remote_procedure_callhttps://en.wikipedia.org/wiki/Enterprise_service_bushttps://en.wikipedia.org/wiki/Message_queuehttps://en.wikipedia.org/wiki/Publish_subscribe

Aclassicexampleofpointtopointmessagingwouldbeanorderqueueinacompany'sbookorderingsystem.Eachorderisrepresentedasamessagewhichissenttotheorderqueue.Let'simaginetherearemanyfrontendorderingsystemswhichsendorderstotheorderqueue.Whenamessagearrivesonthequeueitispersisted-thisensuresthatiftheservercrashestheorderisnotlost.Let'salsoimaginetherearemanyconsumersontheorderqueue-eachrepresentinganinstanceofanorderprocessingcomponent-thesecanbeondifferentphysicalmachinesbutconsumingfromthesamequeue.Themessagingsystemdeliverseachmessagetooneandonlyoneoftheorderingprocessingcomponents.Differentmessagescanbeprocessedbydifferentorderprocessors,butasingleorderisonlyprocessedbyoneorderprocessor-thisensuresordersaren'tprocessedtwice.

Asanorderprocessorreceivesamessage,itfulfillstheorder,sendsorderinformationtothewarehousesystemandthenupdatestheorderdatabasewiththeorderdetails.Onceit'sdonethatitacknowledgesthemessagetotelltheserverthattheorderhasbeenprocessedandcanbeforgottenabout.Oftenthesendtothewarehousesystem,updateindatabaseandacknowledgementwillbecompletedinasingletransactiontoensureACIDproperties.

Publish-Subscribe

Withpublish-subscribemessagingmanysenderscansendmessagestoanentityontheserver,oftencalledatopic(e.g.intheJMSworld).

Therecanbemanysubscriptionsonatopic,asubscriptionisjustanotherwordforaconsumerofatopic.Eachsubscriptionreceivesacopyofeachmessagesenttothetopic.Thisdiffersfromthemessagequeuepatternwhereeachmessageisonlyconsumedbyasingleconsumer.

Subscriptionscanoptionallybedurablewhichmeanstheyretainacopyofeachmessagesenttothetopicuntilthesubscriberconsumesthem-eveniftheservercrashesorisrestartedinbetween.Non-durablesubscriptionsonlylastamaximumofthelifetimeoftheconnectionthatcreatedthem.

Anexampleofpublish-subscribemessagingwouldbeanewsfeed.Asnewsarticlesarecreatedbydifferenteditorsaroundtheworldtheyaresenttoanewsfeedtopic.Therearemanysubscribersaroundtheworldwhoareinterestedinreceivingnewsitems-eachonecreatesasubscriptionandthemessagingsystemensuresthatacopyofeachnewsmessageisdeliveredtoeachsubscription.

DeliveryguaranteesAkeyfeatureofmostmessagingsystemsisreliablemessaging.Withreliablemessagingtheservergivesaguaranteethatthemessagewillbedeliveredonceandonlyoncetoeachconsumerofaqueueoreachdurablesubscriptionofatopic,evenintheeventofsystemfailure.Thisiscrucialformanybusinesses;e.g.youdon'twantyourordersfulfilledmorethanonceoranyofyourorderstobelost.

Inothercasesyoumaynotcareaboutaonceandonlyoncedeliveryguaranteeandarehappytocopewithduplicatedeliveriesorlostmessages-anexampleofthismightbetransientstockpriceupdates-whicharequicklysupersededbythenextupdateonthesamestock.Themessagingsystemallowsyoutoconfigurewhichdeliveryguaranteesyourequire.

Transactions

Messagingsystemstypicallysupportthesendingandacknowledgementofmultiplemessagesinasinglelocaltransaction.ApacheActiveMQArtemisalsosupportsthesendingandacknowledgementofmessageaspartofalargeglobaltransaction-usingtheJavamappingofXA:JTA.

Durability

MessagingConcepts

18

https://en.wikipedia.org/wiki/ACID

Messagesareeitherdurableornondurable.Durablemessageswillbepersistedinpermanentstorageandwillsurviveserverfailureorrestart.Nondurablemessageswillnotsurviveserverfailureorrestart.Examplesofdurablemessagesmightbeordersortrades,wheretheycannotbelost.Anexampleofanondurablemessagemightbeastockpriceupdatewhichistransitoryanddoesn'tneedtosurvivearestart.

MessagingAPIsandprotocols

Howdoclientapplicationsinteractwithmessagingsystemsinordertosendandconsumemessages?

SeveralmessagingsystemsprovidetheirownproprietaryAPIswithwhichtheclientcommunicateswiththemessagingsystem.

Therearealsosomestandardwaysofoperatingwithmessagingsystemsandsomeemergingstandardsinthisspace.

Let'stakeabrieflookatthese:

JavaMessageService(JMS)

JMSispartofOracle'sJavaEEspecification.It'saJavaAPIthatencapsulatesbothmessagequeueandpublish-subscribemessagingpatterns.JMSisalowestcommondenominatorspecification-i.e.itwascreatedtoencapsulatecommonfunctionalityofthealreadyexistingmessagingsystemsthatwereavailableatthetimeofitscreation.

JMSisaverypopularAPIandisimplementedbymostmessagingsystems.JMSisonlyavailabletoclientsrunningJava.

JMSdoesnotdefineastandardwireformat-itonlydefinesaprogrammaticAPIsoJMSclientsandserversfromdifferentvendorscannotdirectlyinteroperatesinceeachwillusethevendor'sowninternalwireprotocol.

ApacheActiveMQArtemisprovidesafullycompliantJMS1.1andJMS2.0clientimplementation.

SystemspecificAPIs

ManysystemsprovidetheirownprogrammaticAPIforwhichtointeractwiththemessagingsystem.Theadvantageofthisitallowsthefullsetofsystemfunctionalitytobeexposedtotheclientapplication.API'slikeJMSarenotnormallyrichenoughtoexposealltheextrafeaturesthatmostmessagingsystemsprovide.

ApacheActiveMQArtemisprovidesitsowncoreclientAPIforclientstouseiftheywishtohaveaccesstofunctionalityoverandabovethataccessibleviatheJMSAPI.

PleaseseeCoreforusingtheCoreAPIwithApacheActiveMQArtemis.

RESTfulAPI

RESTapproachestomessagingareshowingalotinterestrecently.

ItseemsplausiblethatAPIstandardsforcloudcomputingmayconvergeonaRESTstylesetofinterfacesandconsequentlyaRESTmessagingapproachisaverystrongcontenderforbecomingthede-factomethodformessaginginteroperability.

WithaRESTapproachmessagingresourcesaremanipulatedasresourcesdefinedbyaURIandtypicallyusingasimplesetofoperationsonthoseresources,e.g.PUT,POST,GETetc.RESTapproachestomessagingoftenuseHTTPastheirunderlyingprotocol.

TheadvantageofaRESTapproachwithHTTPisinitssimplicityandthefacttheinternetisalreadytunedtodealwithHTTPoptimally.

PleaseseeRestInterfaceforusingApacheActiveMQArtemis'sRESTfulinterface.

AMQP

MessagingConcepts

19

https://en.wikipedia.org/wiki/Java_Message_Servicehttps://en.wikipedia.org/wiki/Representational_State_Transferhttps://en.wikipedia.org/wiki/AMQP

AMQPisaspecificationforinteroperablemessaging.Italsodefinesawireformat,soanyAMQPclientcanworkwithanymessagingsystemthatsupportsAMQP.AMQPclientsareavailableinmanydifferentprogramminglanguages.

ApacheActiveMQArtemisimplementstheAMQP1.0specification.Anyclientthatsupportsthe1.0specificationwillbeabletointeractwithApacheActiveMQArtemis.

PleaseseeAMQPforusingAMQPwithApacheActiveMQArtemis.

MQTT

MQTTisalightweightconnectivityprotocol.Itisdesignedtoruninenvironmentswheredeviceandnetworksareconstrained.OutoftheboxApacheActiveMQArtemissupportsversionMQTT3.1.1.AnyclientsupportingthisversionoftheprotocolwillworkagainstApacheActiveMQArtemis.

PleaseseeMQTTforusingMQTTwithApacheActiveMQArtemis.

STOMP

Stompisaverysimpletextprotocolforinteroperatingwithmessagingsystems.Itdefinesawireformat,sotheoreticallyanyStompclientcanworkwithanymessagingsystemthatsupportsStomp.Stompclientsareavailableinmanydifferentprogramminglanguages.

PleaseseeStompforusingSTOMPwithApacheActiveMQArtemis.

OpenWire

ActiveMQ5.xdefinesitsownwireprotocol:OpenWire.InordertosupportActiveMQ5.xclients,ApacheActiveMQArtemissupportsOpenWire.AnyActiveMQ5.12.xorhighercanbeusedwithApacheActiveMQArtemis.

PleaseseeOpenWireforusingOpenWirewithApacheActiveMQArtemis.

HighAvailability

HighAvailability(HA)meansthatthesystemshouldremainoperationalafterfailureofoneormoreoftheservers.ThedegreeofsupportforHAvariesbetweenvariousmessagingsystems.

ApacheActiveMQArtemisprovidesautomaticfailoverwhereyoursessionsareautomaticallyreconnectedtothebackupserveroneventofliveserverfailure.

FormoreinformationonHA,pleaseseeHighAvailabilityandFailover.

Clusters

Manymessagingsystemsallowyoutocreategroupsofmessagingserverscalledclusters.Clustersallowtheloadofsendingandconsumingmessagestobespreadovermanyservers.Thisallowsyoursystemtoscalehorizontallybyaddingnewserverstothecluster.

Degreesofsupportforclustersvariesbetweenmessagingsystems,withsomesystemshavingfairlybasicclusterswiththeclustermembersbeinghardlyawareofeachother.

ApacheActiveMQArtemisprovidesveryconfigurablestate-of-the-artclusteringmodelwheremessagescanbeintelligentlyloadbalancedbetweentheserversinthecluster,accordingtothenumberofconsumersoneachnode,andwhethertheyarereadyformessages.

MessagingConcepts

20

https://www.oasis-open.org/committees/tc_home.php?wg_abbrev=amqphttps://mqtt.org/https://stomp.github.io/

ApacheActiveMQArtemisalsohastheabilitytoautomaticallyredistributemessagesbetweennodesofaclustertopreventstarvationonanyparticularnode.

Forfulldetailsonclustering,pleaseseeClusters.

Bridgesandrouting

Somemessagingsystemsallowisolatedclustersorsinglenodestobebridgedtogether,typicallyoverunreliableconnectionslikeawideareanetwork(WAN),ortheinternet.

Abridgenormallyconsumesfromaqueueononeserverandforwardsmessagestoanotherqueueonadifferentserver.Bridgescopewithunreliableconnections,automaticallyreconnectingwhentheconnectionsbecomesavailableagain.

ApacheActiveMQArtemisbridgescanbeconfiguredwithfilterexpressionstoonlyforwardcertainmessages,andtransformationcanalsobehookedin.

ApacheActiveMQArtemisalsoallowsroutingbetweenqueuestobeconfiguredinserversideconfiguration.Thisallowscomplexroutingnetworkstobesetupforwardingorcopyingmessagesfromonedestinationtoanother,formingaglobalnetworkofinterconnectedbrokers.

FormoreinformationpleaseseeCoreBridgesandDivertingandSplittingMessageFlows.

MessagingConcepts

21

CoreArchitectureApacheActiveMQArtemiscoreisdesignedsimplyassetofPlainOldJavaObjects(POJOs)-wehopeyoulikeitsclean-cutdesign.

EachApacheActiveMQArtemisserverhasitsownultrahighperformancepersistentjournal,whichitusesformessageandotherpersistence.

Usingahighperformancejournalallowsoutrageouspersistencemessageperformance,somethingnotachievablewhenusingarelationaldatabaseforpersistence(althoughJDBCisstillanoptionifnecessary).

ApacheActiveMQArtemisclients,potentiallyondifferentphysicalmachines,interactwiththeApacheActiveMQArtemisbroker.ApacheActiveMQArtemiscurrentlyshipstwoAPIimplementationsformessagingattheclientside:

1. CoreclientAPI.ThisisasimpleintuitiveJavaAPIthatisalignedwiththeArtemisinternalCore.Allowingmorecontrolofbrokerobjects(e.gdirectcreationofaddressesandqueues).TheCoreAPIalsooffersafullsetofmessagingfunctionalitywithoutsomeofthecomplexitiesofJMS.

2. JMS2.0clientAPI.ThestandardJMSAPIisavailableattheclientside.

ApacheActiveMQArtemisalsoprovidesdifferentprotocolimplementationsontheserversoyoucanuserespectiveclientsfortheseprotocols:

AMQPOpenWireMQTTSTOMPHornetQ(forusewithHornetQclients).Core(ArtemisCOREprotocol)

JMSsemanticsareimplementedbyaJMSfacadelayerontheclientside.

TheApacheActiveMQArtemisbrokerdoesnotspeakJMSandinfactdoesnotknowanythingaboutJMS,itisaprotocolagnosticmessagingserverdesignedtobeusedwithmultipledifferentprotocols.

WhenauserusestheJMSAPIontheclientside,allJMSinteractionsaretranslatedintooperationsontheApacheActiveMQArtemiscoreclientAPIbeforebeingtransferredoverthewireusingthecoreprotocol.

ThebrokeralwaysjustdealswithcoreAPIinteractions.

Aschematicillustratingthisrelationshipisshowninfigure3.1below:

Architecture

22

Figure3.1showstwouserapplicationsinteractingwithanApacheActiveMQArtemisserver.UserApplication1isusingtheJMSAPI,whileUserApplication2isusingthecoreclientAPIdirectly.

YoucanseefromthediagramthattheJMSAPIisimplementedbyathinfacadelayerontheclientside.

Stand-aloneBrokerThenormalstand-alonemessagingbrokerconfigurationcomprisesacoremessagingbrokerandanumberofprotocolmanagersthatprovidesupportforthevariousprotocolmentionedearlier.

Thestand-alonebrokerconfigurationusesAirlineforbootstrappingtheBroker.

Thestand-alonebrokerarchitectureisshowninfigure3.3below:

Architecture

23

https://github.com/airlift/airline

FormoreinformationonserverconfigurationfilesseeServerConfiguration

EmbeddedBroker

ApacheActiveMQArtemiscoreisdesignedasasetofsimplePOJOssoifyouhaveanapplicationthatrequiresmessagingfunctionalityinternallybutyoudon'twanttoexposethatasanApacheActiveMQArtemisbrokeryoucandirectlyinstantiateandembedbrokersinyourownapplication.

ReadmoreaboutembeddingApacheActiveMQArtemis.

IntegratedwithaJavaEEapplicationserverApacheActiveMQArtemisprovidesitsownfullyfunctionalJavaConnectorArchitecture(JCA)adaptorwhichenablesittobeintegratedeasilyintoanyJavaEEcompliantapplicationserverorservletengine.

JavaEEapplicationserversprovideMessageDrivenBeans(MDBs),whichareaspecialtypeofEnterpriseJavaBeans(EJBs)thatcanprocessmessagesfromsourcessuchasJMSsystemsormailsystems.

ProbablythemostcommonuseofanMDBistoconsumemessagesfromaJMSmessagingsystem.

AccordingtotheJavaEEspecification,aJavaEEapplicationserverusesaJCAadaptertointegratewithaJMSmessagingsystemsoitcanconsumemessagesforMDBs.

However,theJCAadapterisnotonlyusedbytheJavaEEapplicationserverforconsumingmessagesviaMDBs,itisalsousedwhensendingmessagetotheJMSmessagingsysteme.g.frominsideanEJBorservlet.

WhenintegratingwithaJMSmessagingsystemfrominsideaJavaEEapplicationserveritisalwaysrecommendedthatthisisdoneviaaJCAadaptor.Infact,communicatingwithaJMSmessagingsystemdirectly,withoutusingJCAwouldbeillegalaccordingtotheJavaEEspecification.

Theapplicationserver'sJCAserviceprovidesextrafunctionalitysuchasconnectionpoolingandautomatictransactionenlistment,whicharedesirablewhenusingmessaging,say,frominsideanEJB.ItispossibletotalktoaJMSmessagingsystemdirectlyfromanEJB,MDBorservletwithoutgoingthroughaJCAadapter,butthisisnotrecommendedsinceyouwillnotbeabletotakeadvantageoftheJCAfeatures,suchascachingofJMSsessions,whichcanresultinpoorperformance.

Architecture

24

Figure3.2belowshowsaJavaEEapplicationserverintegratingwithaApacheActiveMQArtemisserverviatheApacheActiveMQArtemisJCAadaptor.NotethatallcommunicationbetweenEJBsessionsorentitybeansandMessageDrivenbeansgothroughtheadaptorandnotdirectlytoApacheActiveMQArtemis.

ThelargearrowwiththeprohibitedsignshowsanEJBsessionbeantalkingdirectlytotheApacheActiveMQArtemisserver.Thisisnotrecommendedasyou'llmostlikelyendupcreatinganewconnectionandsessioneverytimeyouwanttointeractfromtheEJB,whichisananti-pattern.

Architecture

25

UsingtheServerThischapterwillfamiliariseyouwithhowtousetheApacheActiveMQArtemisserver.

We'llshowwhereitis,howtostartandstopit,andwe'lldescribethedirectorylayoutandwhatallthefilesareandwhattheydo.

FortheremainderofthischapterwhenwetalkabouttheApacheActiveMQArtemisserverwemeantheApacheActiveMQArtemisstandaloneserver,initsdefaultconfigurationwithaJMSServiceenabled.

ThisdocumentwillrefertothefullpathofthedirectorywheretheActiveMQdistributionhasbeenextractedtoas${ARTEMIS_HOME}directory.

Installation

Afterdownloadingthedistribution,thefollowinghighlightssomeimportantfoldersonthedistribution:

|___bin

|

|___examples

||___common

||___features

||___perf

||___protocols

|

|___lib

||___client

|

|___schema

|

|___web

|___api

|___hacking-guide

|___migration-guide

|___user-manual

bin-binariesandscriptsneededtorunActiveMQArtemis.

examples-Allmannerofexamples.Pleaserefertotheexampleschapterfordetailsonhowtorunthem.

lib-jarsandlibrariesneededtorunActiveMQArtemis

schema-XMLSchemasusedtovalidateActiveMQArtemisconfigurationfiles

web-Thefolderwherethewebcontextisloadedwhenthebrokerruns.

api-Theapidocumentationisplacedunderthewebfolder.

user-manual-Theusermanualisplacedunderthewebfolder.

CreatingaBrokerInstance

Abrokerinstanceisthedirectorycontainingalltheconfigurationandruntimedata,suchaslogsanddatafiles,associatedwithabrokerprocess.Itisrecommendedthatyoudonotcreatetheinstancedirectoryunder ${ARTEMIS_HOME}.ThisseparationisencouragedsothatyoucanmoreeasilyupgradewhenthenextversionofActiveMQArtemisisreleased.

OnUnixsystems,itisacommonconventiontostorethiskindofruntimedataunderthe /var/libdirectory.Forexample,tocreateaninstanceat'/var/lib/mybroker',runthefollowingcommandsinyourcommandlineshell:

UsingtheServer

26

cd/var/lib

${ARTEMIS_HOME}/bin/artemiscreatemybroker

Abrokerinstancedirectorywillcontainthefollowingsubdirectories:

bin:holdsexecutionscriptsassociatedwiththisinstance.etc:holdtheinstanceconfigurationfilesdata:holdsthedatafilesusedforstoringpersistentmessageslog:holdsrotatinglogfilestmp:holdstemporaryfilesthataresafetodeletebetweenbrokerruns

Atthispointyoumaywanttoadjustthedefaultconfigurationlocatedinthe etcdirectory.

Options

Thereareseveraloptionsyoucanusewhencreatinganinstance.

Forafulllistofupdatedpropertiesalwaysuse:

$./artemishelpcreate

NAME

artemiscreate-createsanewbrokerinstance

SYNOPSIS

artemiscreate[--addresses][--aio][--allow-anonymous]

[--autocreate][--blocking][--cluster-password]

[--cluster-user][--clustered][--data]

[--default-port][--disable-persistence]

[--encoding][--etc][--failover-on-shutdown][--force]

[--global-max-size][--home][--host]

[--http-host][--http-port]

[--java-options][--mapped][--max-hops]

[--message-load-balancing][--name]

[--nio][--no-amqp-acceptor][--no-autocreate][--no-autotune]

[--no-fsync][--no-hornetq-acceptor][--no-mqtt-acceptor]

[--no-stomp-acceptor][--no-web][--paging][--password]

[--ping][--port-offset][--queues]

[--replicated][--require-login][--role][--shared-store]

[--silent][--slave][--ssl-key]

[--ssl-key-password][--ssl-trust]

[--ssl-trust-password][--use-client-auth]

[--user][--verbose][--]

OPTIONS

--addresses

Commaseparatedlistofaddresses

--aio

Setsthejournalasasyncio.

--allow-anonymous

Enablesanonymousconfigurationonsecurity,oppositeof

--require-login(Default:input)

--autocreate

Autocreateaddresses.(default:true)

--blocking

Blockproducerswhenaddressbecomesfull,oppositeof--paging

(Default:false)

--cluster-password

Theclusterpasswordtouseforclustering.(Default:input)

UsingtheServer

27

--cluster-user

Theclusterusertouseforclustering.(Default:input)

--clustered

Enableclustering

--data

DirectorywhereActiveMQdataarestored.Pathscanbeabsoluteor

relativetoartemis.instancedirectory('data'bydefault)

--default-port

Theportnumbertouseforthemain'artemis'acceptor(Default:

61616)

--disable-persistence

Disablemessagepersistencetothejournal

--encoding

Theencodingthattextfilesshoulduse

--etc

DirectorywhereActiveMQconfigurationislocated.Pathscanbeabsoluteor

relativetoartemis.instancedirectory('etc'bydefault)

--failover-on-shutdown

Validforsharedstore:willshutdowntriggerafailover?(Default:

false)

--force

Overwriteconfigurationatdestinationdirectory

--global-max-size

Maximumamountofmemorywhichmessagedatamayconsume(Default:

Undefined,halfofthesystem'smemory)

--home

DirectorywhereActiveMQArtemisisinstalled

--host

Thehostnameofthebroker(Default:0.0.0.0orinputifclustered)

--http-host

Thehostnametouseforembeddedwebserver(Default:localhost)

--http-port

Theportnumbertouseforembeddedwebserver(Default:8161)

--java-options

Extrajavaoptionstobepassedtotheprofile

--mapped

Setsthejournalasmapped.

--max-hops

Numberofhopsontheclusterconfiguration

--message-load-balancing

Loadbalancingpolicyoncluster.[ON_DEMAND(default)|STRICT|

OFF]

--name

Thenameofthebroker(Default:sameashost)

--nio

Setsthejournalasnio.

--no-amqp-acceptor

DisabletheAMQPspecificacceptor.

UsingtheServer

28

--no-autocreate

DisableAutocreateaddresses.

--no-autotune

Disableautotuningonthejournal.

--no-fsync

Disableusageoffdatasync(channel.force(false)fromjavanio)on

thejournal

--no-hornetq-acceptor

DisabletheHornetQspecificacceptor.

--no-mqtt-acceptor

DisabletheMQTTspecificacceptor.

--no-stomp-acceptor

DisabletheSTOMPspecificacceptor.

--no-web

Removetheweb-serverdefinitionfrombootstrap.xml

--paging

Pagemessagestodiskwhenaddressbecomesfull,oppositeof

--blocking(Default:true)

--password

Theuser'spassword(Default:input)

--ping

Acommaseparatedstringtobepassedontothebrokerconfigas

network-check-list.Thebrokerwillshutdownwhenallthese

addressesareunreachable.

--port-offset

Offsetstheportsofeveryacceptor

--queues

Commaseparatedlistofqueues.

--replicated

Enablebrokerreplication

--require-login

Thiswillconfiguresecuritytorequireuser/password,oppositeof

--allow-anonymous

--role

Thenamefortherolecreated(Default:amq)

--shared-store

Enablebrokersharedstore

--silent

Itwilldisablealltheinputs,anditwouldmakeabestguessfor

anyrequiredinput

--slave

Validforsharedstoreorreplication:thisisaslaveserver?

--ssl-key

Thekeystorepathforembeddedwebserver

--ssl-key-password

Thekeystorepassword

--ssl-trust

Thetruststorepathincaseofclientauthentication

UsingtheServer

29

--ssl-trust-password

Thetruststorepassword

--use-client-auth

Iftheembeddedserverrequiresclientauthentication

--user

Theusername(Default:input)

--verbose

Addsmoreinformationontheexecution

--

Thisoptioncanbeusedtoseparatecommand-lineoptionsfromthe

listofargument,(usefulwhenargumentsmightbemistakenfor

command-lineoptions

Theinstancedirectorytoholdthebroker'sconfigurationanddata.

Pathmustbewritable.

Someofthesepropertiesmaybemandatoryincertainconfigurationsandthesystemmayaskyouforadditionalinput.

./artemiscreate/usr/server

CreatingActiveMQArtemisinstanceat:/user/server

--user:isamandatoryproperty!

Pleaseprovidethedefaultusername:

admin

--password:ismandatorywiththisconfiguration:

Pleaseprovidethedefaultpassword:

--allow-anonymous|--require-login:isamandatoryproperty!

Allowanonymousaccess?,validvaluesareY,N,True,False

y

Autotuningjournal...

done!Yoursystemcanmake0.34writespermillisecond,yourjournal-buffer-timeoutwillbe2956000

Youcannowstartthebrokerbyexecuting:

"/user/server/bin/artemis"run

Oryoucanrunthebrokerinthebackgroundusing:

"/user/server/bin/artemis-service"start

StartingandStoppingaBrokerInstance

Assumingyoucreatedthebrokerinstanceunder /var/lib/mybrokerallyouneedtodostartrunningthebrokerinstanceisexecute:

/var/lib/mybroker/bin/artemisrun

Nowthatthebrokerisrunning,youcanoptionallyrunsomeoftheincludedexamplestoverifythethebrokerisrunningproperly.

TostoptheApacheActiveMQArtemisinstanceyouwillusethesame artemisscript,butwiththe stopargument.Example:

/var/lib/mybroker/bin/artemisstop

UsingtheServer

30

PleasenotethatApacheActiveMQArtemisrequiresaJava7orlaterruntimetorun.

Bydefaultthe etc/bootstrap.xmlconfigurationisused.Theconfigurationcanbechangede.g.byrunning ./artemisrun--xml:path/to/bootstrap.xmloranotherconfigofyourchoosing.

Environmentvariablesareusedtoprovideeaseofchangingports,hostsanddatadirectoriesusedandcanbefoundinetc/artemis.profileonlinuxand etc\artemis.profile.cmdonWindows.

ServerJVMsettingsTherunscriptssetsomeJVMsettingsfortuningthegarbagecollectionpolicyandheapsize.WerecommendusingaparallelgarbagecollectionalgorithmtosmoothoutlatencyandminimiselargeGCpauses.

BydefaultApacheActiveMQArtemisrunsinamaximumof1GiBofRAM.Toincreasethememorysettingschangethe -Xmsand -XmxmemorysettingsasyouwouldforanyJavaprogram.

IfyouwishtoaddanymoreJVMargumentsortunetheexistingones,therunscriptsaretheplacetodoit.

LibraryPathIfyou'reusingtheAsynchronousIOJournalonLinux,youneedtospecify java.library.pathasapropertyonyourJavaoptions.Thisisdoneautomaticallyinthescripts.

Ifyoudon'tspecify java.library.pathatyourJavaoptionsthentheJVMwillusetheenvironmentvariable LD_LIBRARY_PATH.

YouwillneedtomakesurelibaioisinstalledonLinux.Formoreinformationrefertothelibaiochapter.

Systemproperties

ApacheActiveMQArtemiscantakeasystempropertyonthecommandlineforconfiguringlogging.

Formoreinformationonconfiguringlogging,pleaseseethesectiononLogging.

ConfigurationfilesTheconfigurationfileusedtobootstraptheserver(e.g. bootstrap.xmlbydefault)referencesthespecificbrokerconfigurationfiles.

broker.xml.ThisisthemainActiveMQconfigurationfile.Alltheparametersinthisfilearedescribedhere

Itisalsopossibletousesystempropertysubstitutioninalltheconfigurationfiles.byreplacingavaluewiththenameofasystemproperty.Hereisanexampleofthiswithaconnectorconfiguration:

tcp://${activemq.remoting.netty.host:localhost}:${activemq.remoting.netty.port:61616}

Hereyoucanseewehavereplaced2valueswithsystemproperties activemq.remoting.netty.hostandactivemq.remoting.netty.port.Thesevalueswillbereplacedbythevaluefoundinthesystempropertyifthereisone,ifnottheydefaultbacktolocalhostor61616respectively.Itisalsopossibletonotsupplyadefault.i.e.${activemq.remoting.netty.host},howeverthesystempropertymustbesuppliedinthatcase.

Bootstrapconfigurationfile

UsingtheServer

31

Thestand-aloneserverisbasicallyasetofPOJOswhichareinstantiatedbyAirlinecommands.

Thebootstrapfileisverysimple.Let'stakealookatanexample:

server-Instantiatesacoreserverusingtheconfigurationfilefromthe configurationattribute.ThisisthemainbrokerPOJOnecessarytodoalltherealmessagingwork.

jaas-security-ConfiguresJAAS-basedsecurityfortheserver.The domainattributereferstotherelevantloginmoduleentryin login.config.Ifdifferentbehaviorisneededthenacustomsecuritymanagercanbeconfiguredbyreplacingjaas-securitywith security-manager.Seethe"CustomSecurityManager"sectioninthesecuritychapterformoredetails.

web-ConfiguresanembeddedJettyinstancetoservewebapplicationsliketheadminconsole.

Brokerconfigurationfile

TheconfigurationfortheApacheActiveMQArtemiscoreserveriscontainedin broker.xml.ThisiswhattheFileConfigurationbeanusestoconfigurethemessagingserver.

TherearemanyattributeswhichyoucanconfigureApacheActiveMQArtemis.Inmostcasesthedefaultswilldofine,infacteveryattributecanbedefaultedwhichmeansafilewithasingleempty configurationelementisavalidconfigurationfile.Thedifferentconfigurationwillbeexplainedthroughoutthemanualoryoucanrefertotheconfigurationreferencehere.

WindowsServer

OnwindowsyouwillhavetheoptiontorunActiveMQArtemisasaservice.Justusethefollowingcommandtoinstallit:

$./artemis-service.exeinstall

Thecreateprocessshouldgiveyouahintoftheavailablecommandsavailablefortheartemis-service.exe

AddingBootstrapDependencies

Bootstrapdependencieslikelogginghandlersmustbeaccessiblebythelogmanageratboottime.Packagethedependencyinajarandputitonthebootclasspathbeforeoflogmanagerjar.Thiscanbedoneappendingthejaratthevariable JAVA_ARGS,definedin artemis.profile,withtheoption -Xbootclasspath/a.

AddingRuntimeDependencies

UsingtheServer

32

Runtimedependencieslikediverts,transformers,brokerplugins,JDBCdrivers,passworddecoders,etc.mustbeaccessiblebythebrokeratruntime.Packagethedependencyinajar,andputitonthebroker'sclasspath.Thiscanbedonebyplacingthejarfileinthe libdirectoryofthebrokerdistributionitselforinthe libdirectoryofthebrokerinstance.Abrokerinstancedoesnothavea libdirectorybydefaultsoitmayneedtobecreated.Itshouldbeonthe"top"levelwiththe bin, data, log,etc.directories.

UsingtheServer

33

UpgradingtheBrokerApacheActiveMQ5.x(andpreviousversions)isrunnableoutoftheboxbyexecutingthecommand: ./bin/activemqrun.TheActiveMQArtemisbrokerfollowsadifferentparadigmwheretheprojectdistributionservesasthebroker"home"andoneormorebroker"instances"arecreatedwhichreferencethe"home"forresources(e.g.jarfiles)whichcanbesafelysharedbetweenbrokerinstances.Therefore,aninstanceofthebrokermustbecreatedbeforeitcanberun.Thismayseemslikeanoverheadatfirstglance,butitbecomesverypracticalwhenupdatingtoanewArtemisversionforexample.

TocreateanArtemisbrokerinstancenavigateintotheArtemishomefolderandrun: ./bin/artemiscreate/path/to/myBrokerInstanceonthecommandline.

Becauseofthisseparationit'sveryeasytoupgradeArtemisinmostcases.

Note:

It'srecommendedtochooseafolderdifferentthantheonwhereApacheArtemiswasdownloaded.ThisseparationallowsyourunmultiplebrokerinstanceswiththesameArtemis"home"forexample.ItalsosimplifiesupdatingtonewerversionsofArtemis.

GeneralUpgradeProcedureUpgradingmayrequiresomespecificstepsnotedintheversions,butthegeneralprocessisasfollows:

1. Navigatetothe etcfolderofthebrokerinstancethat'sbeingupgraded2. Open artemis.profile( artemis.profile.cmdonWindows).Itcontainsapropertywhichisrelevantfortheupgrade:

ARTEMIS_HOME='/path/to/apache-artemis-version'

IfyourunArtemisasaserviceonwindowsyouhavetodothefollowingadditionalsteps:

1. Navigatetothe binfolderofthebrokerinstancethat'sbeingupgraded2. Open artemis-service.xml.Itcontainsapropertywhichisrelevantfortheupgrade:

The ARTEMIS_HOMEpropertyisusedtolinktheinstancewiththehome.Inmostcasestheinstancecanbeupgradedtoanewerversionsimplybychangingthevalueofthispropertytothelocationofthenewbrokerhome.Pleaserefertotheaforementionedversionsdocumentforadditionalupgradesteps(ifrequired).

Upgrading

34

AddressingModelApacheActiveMQArtemishasauniqueaddressingmodelthatisbothpowerfulandflexibleandthatoffersgreatperformance.Theaddressingmodelcomprisesthreemainconcepts:addresses,queues,androutingtypes.

Address

Anaddressrepresentsamessagingendpoint.Withintheconfiguration,atypicaladdressisgivenauniquename,0ormorequeues,andaroutingtype.

Queue

Aqueueisassociatedwithanaddress.Therecanbemultiplequeuesperaddress.Onceanincomingmessageismatchedtoanaddress,themessagewillbesentontooneormoreofitsqueues,dependingontheroutingtypeconfigured.Queuescanbeconfiguredtobeautomaticallycreatedanddeleted.

RoutingTypes

Aroutingtypedetermineshowmessagesaresenttothequeuesassociatedwithanaddress.AnApacheActiveMQArtemisaddresscanbeconfiguredwithtwodifferentroutingtypes.

Table1.RoutingTypes

Ifyouwantyourmessagesroutedto... Usethisroutingtype...

Asinglequeuewithinthematchingaddress,inapoint-to-pointmanner. Anycast

Everyqueuewithinthematchingaddress,inapublish-subscribemanner. Multicast

Note:Itispossibletodefinemorethanoneroutingtypeperaddress,butthistypicallyresultsinananti-patternandisthereforenotrecommended.Ifanaddressdoesusebothroutingtypes,however,andtheclientdoesnotshowapreferenceforeitherone,thebrokertypicallydefaultstotheanycastroutingtype.

TheoneexceptioniswhentheclientusestheMQTTprotocol.Inthatcase,thedefaultroutingtypeismulticast.

Foradditionaldetailsabouttheseconceptsrefertothecorechapter.

BasicAddressConfiguration

Thefollowingexamplesshowhowtoconfigurebasicpointtopointandpublishsubscribeaddresses.

Point-to-PointMessaging

Point-to-pointmessagingisacommonscenarioinwhichamessagesentbyaproducerhasonlyoneconsumer.AMQPandJMSmessageproducersandconsumerscanmakeuseofpoint-to-pointmessagingqueues,forexample.Defineananycastroutingtypeforanaddresssothatitsqueuesreceivemessagesinapoint-to-pointmanner.

Whenamessageisreceivedonanaddressusinganycast,ApacheActiveMQArtemislocatesthequeueassociatedwiththeaddressandroutesthemessagetoit.Whenconsumersrequesttoconsumefromtheaddress,thebrokerlocatestherelevantqueueandassociatesthisqueuewiththeappropriateconsumers.Ifmultipleconsumersareconnectedtothesamequeue,messagesaredistributedamongsteachconsumerequally,providingtheconsumersareequallyabletohandlethem.

AddressModel

35

Figure1.PointtoPointMessaging

UsingtheAnycastRoutingType

Openthefile /etc/broker.xmlforediting.

Addanaddressconfigurationelementanditsassociatedqueueiftheydonotexistalready.

Note:FornormalPointtoPointsemantics,thequeuenameMUSTmatchtheaddressname.

Publish-SubscribeMessaging

Inapublish-subscribescenario,messagesaresenttoeveryconsumersubscribedtoanaddress.JMStopicsandMQTTsubscriptionsaretwoexamplesofpublish-subscribemessaging.

Toconfigureanaddresswithpublish-subscribesemantics,createanaddresswiththemulticastroutingtype.

Figure2.Publish-Subscribe

UsingtheMulticastRoutingType

AddressModel

36


Addanaddressconfigurationelementwithmulticastroutingtype.

Whenclientsconnecttoanaddresswiththemulticastelement,asubscriptionqueuefortheclientwillbeautomaticallycreatedfortheclient.Itisalsopossibletopre-configuresubscriptionqueuesandconnecttothemdirectlyusingthequeue'sFullyQualifiedQueuenames.

Optionallyaddoneormorequeueelementstotheaddressandwrapthemulticastelementaroundthem.Thisstepistypicallynotneededsincethebrokerwillautomaticallycreateaqueueforeachsubscriptionrequestedbyaclient.

Figure3.Point-to-PointwithTwoQueues

Point-to-PointAddressmultipleQueues

Itisactuallypossibletodefinemorethanonequeueonanaddresswithananycastroutingtype.Whenmessagesarereceivedonsuchanaddress,theyarefirstlydistributedevenlyacrossallthedefinedqueues.UsingFullyQualifiedQueuenames,clientsareabletoselectthequeuethattheywouldliketosubscribeto.Shouldmorethanoneconsumerconnectdirectlytoasinglequeue,ApacheActiveMQArtemiswilltakecareofdistributingmessagesbetweenthem,asintheexampleabove.

Figure3.Point-to-PointwithTwoQueues

Note:ThisishowApacheActiveMQArtemishandlesloadbalancingofqueuesacrossmultiplenodesinacluster.ConfiguringaPoint-to-PointAddresswithtwoqueues,openthefile /etc/broker.xmlforediting.

AddanaddressconfigurationwithAnycastroutingtypeelementanditsassociatedqueues.

AddressModel

37

Point-to-PointandPublish-SubscribeAddresses

Itispossibletodefineanaddresswithbothpoint-to-pointandpublish-subscribesemanticsenabled.Whilenottypicallyrecommend,thiscanbeusefulwhenyouwant,forexample,aJMSQueuesayordersandaJMSTopicnamedorders.Thedifferentroutingtypesmaketheaddressesappeartobedistinct.

UsinganexampleofJMSClients,themessagessentbyaJMSmessageproducerwillberoutedusingtheanycastroutingtype.MessagessentbyaJMStopicproducerwillusethemulticastroutingtype.InadditionwhenaJMStopicconsumerattaches,itwillbeattachedtoit’sownsubscriptionqueue.JMSqueueconsumerwillbeattachedtotheanycastqueue.

Figure4.Point-to-PointandPublish-Subscribe

Note:Thebehaviorinthisscenarioisdependentontheprotocolbeingused.ForJMSthereisacleardistinctionbetweentopicandqueueproducersandconsumers,whichmakethelogicstraightforward.OtherprotocolslikeAMQPdonotmakethisdistinction.AmessagebeingsentviaAMQPwillberoutedbybothanycastandmulticastandconsumerswilldefaulttoanycast.Formoreinformation,pleasecheckthebehaviorofeachprotocolinthesectionsonprotocols.

TheXMLsnippetbelowisanexampleofwhattheconfigurationforanaddressusingbothanycastandmulticastwouldlooklikein /etc/broker.xml.Notethatsubscriptionqueuesaretypicallycreatedondemand,sothereisnoneedtolistspecificqueueelementsinsidethemulticastroutingtype.

Howtofiltermessages

ApacheActiveMQArtemissupportstheabilitytofiltermessagesusingApacheArtemisFilterExpressions.

Filterscanbeappliedintwoplaces,onaqueueandonaconsumer.

QueueFilter

AddressModel

38

Whenafilterisappliedtoaqueue,messagesarefilteredbeforetheyaresenttothequeue.Toaddaqueuefilterusethefilterelementwhenconfiguringaqueue.Openup /etc/broker.xmlandaddanaddresswithaqueue,usingthefilterelementtoconfigureafilteronthisqueue.

Thefilterdefinedaboveensuresthatonlymessageswithanattribute "color='red'"issenttothisqueue.

ConsumerFilters

ConsumerfiltersareappliedaftermessageshavereachedaqueueandaredefinedusingtheappropriateclientAPIs.ThefollowingJMSexampleshowshowconsumerfilterswork.

1. Defineanaddresswithasinglequeue,withnofilterapplied.

...

//Sendsomemessages

for(inti=0;i<3;i++){

TextMessageredMessage=senderSession.createTextMessage("Red");

redMessage.setStringProperty("color","red");

producer.send(redMessage)

TextMessagegreenMessage=senderSession.createTextMessage("Green");

greenMessage.setStringProperty("color","green");

producer.send(greenMessage)

}

Atthispointthequeuewouldhave6messages:red,green,red,green,red,green

MessageConsumerredConsumer=redSession.createConsumer(queue,"color='red'");

TheredConsumerhasafilterthatonlymatches"red"messages.TheredConsumerwillreceive3messages.

red,red,red

Theresultingqueuewouldnowbe

green,green,green

AutomaticAddress/QueueManagement

AddressModel

39

YoucanconfigureApacheActiveMQArtemistoautomaticallycreateaddressesandqueues,andthendeletethemwhentheyarenolongerinuse.Thissavesyoufromhavingtopreconfigureeachaddressandqueuebeforeaclientcanconnecttoit.Automaticcreationanddeletionisconfiguredonaperaddressbasisandiscontrolledbyfollowing:

Parameter Description

auto-create-addresses

Whensettotrue,thebrokerwillcreatetheaddressrequestedbytheclientifitdoesnotexistalready.Thedefaultis true.

auto-delete-addresses

Whensettotrue,thebrokerwillbedeleteanyauto-createdadddressonceallofit’squeueshavebeendeleted.Thedefaultis true

default-address-routing-type

Theroutingtypetouseiftheclientdoesnotspecifyone.Possiblevaluesare MULTICASTandANYCAST.Seeearlierinthischapterformoreinformationaboutroutingtypes.ThedefaultvalueisMULTICAST.

AutoAddressCreation

Editthefile /etc/broker.xmlandaddthe auto-create-addresseselementtothe address-settingyouwantthebrokertoautomaticallycreate.

(Optional)Addthe address-settingifitdoesnotexist.Usethematchparameterandthewildcardsyntaxtomatchmorethanonespecificaddress.

Set auto-create-addressesto true

(Optional)Assign MULTICASTor ANYCASTasthedefaultroutingtypefortheaddress.

Theexamplebelowconfiguresan address-settingtobeautomaticallycreatedbythebroker.ThedefaultroutingtypetobeusedifnotspecifiedbytheclientisMULTICAST.Notethatwildcardsyntaxisused.Anyaddressstartingwith/news/politics/willbeautomaticallycreatedbythebroker.

true

MULTICAST

AutoAddressDeletion

Editthefile /etc/broker.xmlandaddthe auto-delete-addresseselementtothe address-settingyouwantthebrokertoautomaticallycreate.

(Optional)Addthe address-settingifitdoesnotexist.Usethematchparameterandthewildcardsyntaxtomatchmorethanonespecificaddress.

Set auto-delete-addressesto true

Theexamplebelowconfiguresan address-settingtobeautomaticallydeletedbythebroker.Notethatwildcardsyntaxisused.Anyaddressrequestbytheclientthatstartswith /news/politics/isconfiguredtobeautomaticallydeletedbythebroker.

true

MULTICAST

"FullyQualified"QueueNames

AddressModel

40

Internallythebrokermapsaclient’srequestforanaddresstospecificqueues.Thebrokerdecidesonbehalfoftheclientwhichqueuestosendmessagestoorfromwhichqueuetoreceivemessages.However,moreadvancedusecasesmightrequirethattheclientspecifyaqueuedirectly.Inthesesituationstheclientusesafullyqualifiedqueuename,byspecifyingboththeaddressnameandthequeuename,separatedbya::.

CurrentlyArtemissupportsfullyqualifiedqueuenamesonCore,AMQP,JMS,OpenWire,MQTTandSTOMPprotocolsforreceivingmessagesonly.

SpecifyingaFullyQualifiedQueueName

Inthisexample,theaddressfooisconfiguredwithtwoqueuesq1,q2asshownintheconfigurationbelow.

Intheclientcode,useboththeaddressnameandthequeuenamewhenrequestingaconnectionfromthebroker.Remembertousetwocolons, ::,toseparatethenames,asintheexampleJavacodebelow.

StringFQQN="foo::q1";

Queueq1session.createQueue(FQQN);

MessageConsumerconsumer=session.createConsumer(q1);

UsingPrefixestoDetermineRoutingType

Normally,ifthebrokerreceivesamessagesenttoaparticularaddress,thathasboth ANYCASTand MULTICASTroutingtypesenable,itwillrouteacopyofthemessagetooneofthe ANYCASTqueuesandtoallofthe MULTICASTqueues.

However,clientscanspecifyaspecialprefixwhenconnectingtoanaddresstoindicatewhichkindofroutingtypetouse.TheprefixesarecustomvaluesthataredesignatedusingtheanycastPrefixandmulticastPrefixparameterswithintheURLofanacceptor.

ConfiguringanAnycastPrefix

In /etc/broker.xml,addthe anycastPrefixtotheURLofthedesiredacceptor.Intheexamplebelow,theacceptorisconfiguredtouse anycast://forthe anycastPrefix.Clientcodecanspecify anycast://foo/iftheclientneedstosendamessagetoonlyoneofthe ANYCASTqueues.

tcp://0.0.0.0:61616?protocols=AMQP;anycastPrefix=anycast://

ConfiguringaMulticastPrefix

In /etc/broker.xml,addthe multicastPrefixtotheURLofthedesiredacceptor.Intheexamplebelow,theacceptorisconfiguredtouse multicast://forthe multicastPrefix.Clientcodecanspecify multicast://foo/iftheclientneedstosendamessagetoonlyoneofthe MULTICASTqueues.

tcp://0.0.0.0:61616?protocols=AMQP;multicastPrefix=multicast://

AddressModel

41

AdvancedAddressConfiguration

StaticSubscriptionQueues

Inmostcasesit’snotnecessarytostaticallyconfiguresubscriptionqueues.Therelevantprotocolmanagerstakecareofdynamicallycreatingsubscriptionqueueswhenclientsrequesttosubscribetoanaddress.Thetypeofsubscriptionqueuecreateddependsonwhatpropertiestheclientrequest.Forexample,durable,non-shared,sharedetc.Protocolmanagersusespecialqueuenamingconventionstoidentifywhichqueuesbelongtowhichconsumersandusersneednotworryaboutthedetails.

However,therearescenarioswhereausermaywanttousebrokersideconfigurationtostaticallyconfigureasubscriptionandlaterconnecttothatqueuedirectlyusingaFullyQualifiedQueuename.Theexamplesbelowshowhowtousebrokersideconfigurationtostaticallyconfigureaqueuewithpublishsubscribebehaviorforshared,non-shared,durableandnon-durablesubscriptionbehavior.

Shared,DurableSubscriptionQueueusingmax-consumers

Thedefaultbehaviorforqueuesistonotlimitthenumberconnectedqueueconsumers.Themax-consumersparameterofthequeueelementcanbeusedtolimitthenumberofconnectedconsumersallowedatanyonetime.


true

Non-shared,DurableSubscriptionQueue

Thebrokercanbeconfiguredtopreventmorethanoneconsumerfromconnectingtoaqueueatanyonetime.Thesubscriptionstoqueuesconfiguredthiswayaretherefore"non-shared".Todothissimplysetthemax-consumersparameterto 1:

true

Non-durableSubscriptionQueue

Non-durablesubscriptionsareagainusuallymanagedbytherelevantprotocolmanager,bycreatinganddeletingtemporaryqueues.

Ifauserrequirestopre-createaqueuethatbehaveslikeanon-durablesubscriptionqueuethepurge-on-no-consumersflagcanbeenabledonthequeue.Whenpurge-on-no-consumersissettotrue.Thequeuewillnotstartreceivingmessagesuntilaconsumerisattached.Whenthelastconsumerisdetachedfromthequeue.Thequeueispurged(itsmessagesareremoved)and

AddressModel

42

willnotreceiveanymoremessagesuntilanewconsumerisattached.


ExclusiveConsumerQueue

Ifauserrequirestostaticallyconfigureaqueuethatroutesexclusivelytooneactiveconsumertheexclusiveflagcanbeenabledonthequeue.

Whenexclusiveissettotruethequeuewillroutemessagestotheasingleactiveconsumer.Whentheactiveconsumerthatisbeingroutedtoisdetachedfromthequeue,ifanotheractiveconsumerexist,onewillbechosenandroutingwillnowbeexclusivetoit.

SeeExclusiveQueueforfurtherinformation.


ProtocolManagersA"protocolmanager"mapsprotocol-specificconceptsdowntothecoreaddressingmodel(usingaddresses,queuesandroutingtypes).Forexample,whenaclientsendsaMQTTsubscriptionpacketwiththeaddresses:

/house/room1/lights

/house/room2/lights

TheMQTTprotocolmanagerunderstandsthatthetwoaddressesrequire MULTICASTsemantics.Theprotocolmanagerwillthereforefirstlooktoensurethat MULTICASTisenabledforbothaddresses.Ifnot,itwillattempttodynamicallycreatethem.Ifsuccessful,theprotocolmanagerwillthencreatespecialsubscriptionqueueswithspecialnames,foreachsubscriptionrequestedbytheclient.

Thespecialnameallowstheprotocolmanagertoquicklyidentifytherequiredclientsubscriptionqueuesshouldtheclientdisconnectandreconnectatalaterdate.Ifthesubscriptionistemporarytheprotocolmanagerwilldeletethequeueoncetheclientdisconnects.

Whenaclientrequeststosubscribetoapointtopointaddress.Theprotocolmanagerwilllookupthequeueassociatedwiththepointtopointaddress.Thisqueueshouldhavethesamenameastheaddresss.

Note:Ifthequeueisautocreated,itwillbeautodeletedoncetherearenoconsumersandnomessagesinit.FormoreinformationonautocreateseethenextsectionConfiguringAddressesandQueuesviaAddressSettings

AddressModel

43

ConfiguringAddressesandQueuesviaAddressSettings

Therearesomeattributesthataredefinedagainstanaddresswildcardratherthanaspecificaddress/queue.Hereanexampleofanaddress-settingentrythatwouldbefoundinthe broker.xmlfile.

DLA

ExpiryQueue

123

5000

1.0

0.0

10000

3

100000

-1

20000

PAGE

true

false

false

false

0

-1

0

true

-1

NOTIFY

5

true

true

true

true

true

true

false

0

0

OFF

true

true

0

OFF

200

false

-1

-1

0

Theideawithaddresssettings,isyoucanprovideablockofsettingswhichwillbeappliedagainstanyaddressesthatmatchthestringinthe matchattribute.Intheaboveexamplethesettingswouldonlybeappliedtotheaddress"order.foo"addressbutyoucanalsousewildcardstoapplysettings.

Forexample,ifyouusedthe matchstring queue.#thesettingswouldbeappliedtoalladdresseswhichstartwith queue.

Themeaningofthespecificsettingsareexplainedfullythroughouttheusermanual,howeverhereisabriefdescriptionwithalinktotheappropriatechapterifavailable.

AddressModel

44

dead-letter-addressistheaddresstowhichmessagesaresentwhentheyexceed max-delivery-attempts.Ifnoaddressisdefinedherethensuchmessageswillsimplybediscarded.Readmoreaboutundeliveredmessages.

expiry-addressdefineswheretosendamessagethathasexpired.Ifnoaddressisdefinedherethensuchmessageswillsimplybediscarded.Readmoreaboutmessageexpiry.

expiry-delaydefinestheexpirationtimethatwillbeusedformessageswhichareusingthedefaultexpirationtime(i.e.0).Forexample,if expiry-delayissetto"10"andamessagewhichisusingthedefaultexpirationtime(i.e.0)arrivesthenitsexpirationtimeof"0"willbechangedto"10."However,ifamessagewhichisusinganexpirationtimeof"20"arrivesthenitsexpirationtimewillremainunchanged.Setting expiry-delayto"-1"willdisablethisfeature.Thedefaultis"-1".Readmoreaboutmessageexpiry.

max-delivery-attemptsdefineshowmanytimeacancelledmessagecanberedeliveredbeforesendingtothe dead-letter-address.Readmoreaboutundeliveredmessages.

redelivery-delaydefineshowlongtowaitbeforeattemptingredeliveryofacancelledmessage.Defaultis 0.Readmoreaboutundeliveredmessages.

redelivery-delay-multiplierdefinesthenumberbywhichthe redelivery-delaywillbemultipliedoneachsubsequentredeliveryattempt.Defaultis 1.0.Readmoreaboutundeliveredmessages.

redelivery-collision-avoidance-factordefinesanadditionalfactorusedtocalculateanadjustmenttothe redelivery-delay(upordown).Defaultis 0.0.Validvaluesarebetween0.0and1.0.Readmoreaboutundeliveredmessages.

max-size-bytes, page-size-bytes,& page-max-cache-sizeareusedtoconfigurepagingonanaddress.Thisisexplainedhere.

max-size-bytes-reject-thresholdisusedwiththeaddressfull BLOCKpolicy,themaximumsize(inbytes)anaddresscanreachbeforemessagesstartgettingrejected.Worksincombinationwith max-size-bytesforAMQPclientsonly.Defaultis-1(i.e.nolimit).

address-full-policy.Thisattributecanhaveoneofthefollowingvalues: PAGE, DROP, FAILor BLOCKanddetermineswhathappenswhenanaddresswhere max-size-bytesisspecifiedbecomesfull.Thedefaultvalueis PAGE.IfthevalueisPAGEthenfurthermessageswillbepagedtodisk.Ifthevalueis DROPthenfurthermessageswillbesilentlydropped.Ifthevalueis FAILthenfurthermessageswillbedroppedandanexceptionwillbethrownontheclient-side.Ifthevalueis BLOCKthenclientmessageproducerswillblockwhentheytryandsendfurthermessages.SeetheFlowControlandPagingchaptersformoreinfo.

message-counter-history-day-limitisthenumberofdaystokeepmessagecounterhistoryforthisaddressassumingthatmessage-counter-enabledis true.Defaultis 0.

last-value-queueisdeprecated.See default-last-value-queue.Itdefineswhetheraqueueonlyuseslastvaluesornot.Defaultis false.Readmoreaboutlastvaluequeues.

default-last-value-queuedefineswhetheraqueueonlyuseslastvaluesornot.Defaultis false.Thisvaluecanbeoverriddenatthequeuelevelusingthe last-valueboolean.Readmoreaboutlastvaluequeues.

default-exclusive-queuedefineswhetheraqueuewillserveonlyasingleconsumer.Defaultis false.Thisvaluecanbeoverriddenatthequeuelevelusingthe exclusiveboolean.Readmoreaboutexclusivequeues.

default-consumers-before-dispatchdefinesthenumberofconsumersneededonaqueueboundtothematchingaddressbeforemessageswillbedispatchedtothoseconsumers.Defaultis 0.Thisvaluecanbeoverriddenatthequeuelevelusingtheconsumers-before-dispatchboolean.Thisbehaviorcanbetunedusing delay-before-dispatchonthequeueitselforbyusingthe default-delay-before-dispatchaddress-setting.

default-delay-before-dispatchdefinesthenumberofmillisecondsthebrokerwillwaitfortheconfigurednumberofconsumerstoconnecttothematchingqueuebeforeitwillbegintodispatchmessages.Defaultis -1(waitforever).

AddressModel

45

redistribution-delaydefineshowlongtowaitwhenthelastconsumerisclosedonaqueuebeforeredistributinganymessages.Readmoreaboutclusters.

send-to-dla-on-no-route.Ifamessageissenttoanaddress,buttheserverdoesnotrouteittoanyqueues(e.g.theremightbenoqueuesboundtothataddress,ornoneofthequeueshavefiltersthatmatch)thennormallythatmessagewouldbediscarded.However,ifthisparameteris truethensuchamessagewillinsteadbesenttothe dead-letter-address(DLA)forthataddress,ifitexists.

slow-consumer-threshold.Theminimumrateofmessageconsumptionallowedbeforeaconsumerisconsidered"slow."Measuredinmessages-per-second.Defaultis -1(i.e.disabled);anyothervalidvaluemustbegreaterthan0.Readmoreaboutslowconsumers.

slow-consumer-policy.Whatshouldhappenwhenaslowconsumerisdetected. KILLwillkilltheconsumer'sconnection(whichwillobviouslyimpactanyotherclientthreadsusingthatsameconnection). NOTIFYwillsendaCONSUMER_SLOWmanagementnotificationwhichanapplicationcouldreceiveandtakeactionwith.Readmoreaboutslowconsumers.

slow-consumer-check-period.Howoftentocheckforslowconsumersonaparticularqueue.Measuredinseconds.Defaultis5.Readmoreaboutslowconsumers.

auto-create-jms-queuesisdeprecated.See auto-create-queues.WhetherornotthebrokershouldautomaticallycreateaJMSqueuewhenaJMSmessageissenttoaqueuewhosenamefitstheaddress match(remember,aJMSqueueisjustacorequeuewhichhasthesameaddressandqueuename)oraJMSconsumertriestoconnecttoaqueuewhosenamefitstheaddressmatch.Queueswhichareauto-createdaredurable,non-temporary,andnon-transient.Defaultis true.

auto-delete-jms-queuesisdeprecated.See auto-delete-queues.Whetherornotthebrokershouldautomaticallydeleteauto-createdJMSqueueswhentheyhaveboth0consumersand0messages.Defaultis true.

auto-create-jms-topicsisdeprecated.See auto-create-addresses.WhetherornotthebrokershouldautomaticallycreateaJMStopicwhenaJMSmessageissenttoatopicwhosenamefitstheaddress match(remember,aJMStopicisjustacoreaddresswhichhasoneormorecorequeuesmappedtoit)oraJMSconsumertriestosubscribetoatopicwhosenamefitstheaddress match.Defaultis true.

auto-delete-jms-topicsisdeprecated.See auto-delete-addresses.Whetherornotthebrokershouldautomaticallydeleteauto-createdJMStopicsoncethelastsubscriptiononthetopichasbeenclosed.Defaultis true.

auto-create-queues.Whetherornotthebrokershouldautomaticallycreateaqueuewhenamessageissentoraconsumertriestoconnecttoaqueuewhosenamefitstheaddress match.Queueswhichareauto-createdaredurable,non-temporary,andnon-transient.Defaultis true.Note:automaticqueuecreationdoesnotworkforthecoreclient.ThecoreAPIisalow-levelAPIandisnotmeanttohavesuchautomation.

auto-delete-queues.Whetherornotthebrokershouldautomaticallydeleteauto-createdqueueswhentheyhaveboth0consumersandthemessagecountislessthanorequalto auto-delete-queues-message-count.Defaultis true.

auto-delete-created-queues.Whetherornotthebrokershouldautomaticallydeletecreatedqueueswhentheyhaveboth0consumersandthemessagecountislessthanorequalto auto-delete-queues-message-count.Defaultis false.

auto-delete-queues-delay.Howlongtowait(inmilliseconds)beforedeletingauto-createdqueuesafterthequeuehas0consumersandthemessagecountislessthanorequalto auto-delete-queues-message-count.Defaultis 0(deleteimmediately).Thebroker's address-queue-scan-periodcontrolshowoften(inmilliseconds)queuesarescannedforpotentialdeletion.Use -1todisablescanning.Thedefaultscanvalueis 30000.

auto-delete-queues-message-count.Themessagecountthatthequeuemustbelessthanorequaltobeforedeletingauto-createdqueues.Todisablemessagecountcheck -1canbeset.Defaultis 0(emptyqueue).

Note:theaboveauto-deleteaddresssettingscanalsobeconfiguredindividuallyatthequeuelevelwhenaclientautocreatesthequeue.

ForCoreAPIitisexposedincreateQueuemethods.

AddressModel

46

ForCoreJMSyoucansetitusingthedestinationqueueattributes my.destination?auto-delete=true&auto-delete-delay=120000&auto-delete-message-count=-1

config-delete-queues.Howthebrokershouldhandlequeuesdeletedonconfigreload,bydeletepolicy: OFFor FORCE.Defaultis OFF.Readmoreaboutconfigurationreload.

auto-create-addresses.Whetherornotthebrokershouldautomaticallycreateanaddresswhenamessageissenttooraconsumertriestoconsumefromaqueuewhichismappedtoanaddresswhosenamefitstheaddress match.Defaultis true.Note:automaticaddresscreationdoesnotworkforthecoreclient.ThecoreAPIisalow-levelAPIandisnotmeanttohavesuchautomation.

auto-delete-addresses.Whetherornotthebrokershouldautomaticallydeleteauto-createdaddressesoncetheaddressnolongerhasanyqueues.Defaultis true.

auto-delete-addresses-delay.Howlongtowait(inmilliseconds)beforedeletingauto-createdaddressesaftertheynolongerhaveanyqueues.Defaultis 0(deleteimmediately).Thebroker's address-queue-scan-periodcontrolshowoften(inmilliseconds)addressesarescannedforpotentialdeletion.Use -1todisablescanning.Thedefaultscanvalueis 30000.

config-delete-addresses.Howthebrokershouldhandleaddressesdeletedonconfigreload,bydeletepolicy: OFFor FORCE.Defaultis OFF.Readmoreaboutconfigurationreload.

management-browse-page-sizeisthenumberofmessagesamanagementresourcecanbrowse.Thisisrelevantforthe"browse"managementmethodexposedonthequeuecontrol.Defaultis 200.

default-purge-on-no-consumersdefinesaqueue'sdefault purge-on-no-consumerssettingifnoneisprovidedonthequeueitself.Defaultis false.Thisvaluecanbeoverriddenatthequeuelevelusingthe purge-on-no-consumersboolean.Readmoreaboutthisfunctionality.

default-max-consumersdefinesaqueue'sdefault max-consumerssettingifnoneisprovidedonthequeueitself.Defaultis -1(i.e.nolimit).Thisvaluecanbeoverriddenatthequeuelevelusingthe max-consumersboolean.Readmoreaboutthisfunctionality.

default-queue-routing-typedefinestherouting-typeforanauto-createdqueueifthebrokerisunabletodeterminetherouting-typebasedontheclientand/orprotocolsemantics.Defaultis MULTICAST.Readmoreaboutroutingtypes.

default-address-routing-typedefinestherouting-typeforanauto-createdaddressifthebrokerisunabletodeterminetherouting-typebasedontheclientand/orprotocolsemantics.Defaultis MULTICAST.Readmoreaboutroutingtypes.

default-consumer-window-sizedefinesthedefault consumerWindowSizevaluefora COREprotocolconsumer,ifnotdefinedthedefaultwillbesetto1MiB(1024*1024bytes).Theconsumerwillusethisvalueasthewindowsizeifthevalueisnotsetontheclient.Readmoreaboutflowcontrol.

default-ring-sizedefinesthedefault ring-sizevalueforanymatchingqueuewhichdoesn'thave ring-sizeexplicitlydefined.Ifnotdefinedthedefaultwillbesetto-1.Readmoreaboutringqueues.

retroactive-message-countdefinesthenumberofmessagestopreserveforfuturequeuescreatedonthematchingaddress.Defaultsto0.Readmoreaboutretroactiveaddresses.

AddressModel

47

ProtocolsandInteroperabilityApacheActiveMQArtemishasapowerful&flexiblecorewhichprovidesafoundationuponwhichotherprotocolscanbeimplemented.Eachprotocolimplementationtranslatestheideasofitsspecificprotocolontothiscore.

Thebrokershipswithaclientimplementationwhichinteractsdirectlywiththiscore.Ituseswhat'scalledthe"core"API,anditcommunicatesoverthenetworkusingthe"core"protocol.

SupportedProtocols&APIs

Thebrokerhasapluggableprotocolarchitecture.Protocolpluginscomeintheformofprotocolmodules.Eachprotocolmoduleisincludedonthebroker'sclasspathandloadedbythebrokeratboottime.Thebrokershipswith5protocolmodulesoutofthebox.The5modulesoffersupportforthefollowingprotocols:

AMQPOpenWireMQTTSTOMPHornetQ

APIsandOtherInterfaces

AlthoughJMSisastandardizedAPI,itdoesnotdefineanetworkprotocol.TheActiveMQArtemisJMS2.0clientisimplementedontopofthecoreprotocol.Wealsoprovideaclient-sideJNDIimplementation.

ThebrokeralsoshipswithaRESTmessaginginterface(nottobeconfusedwiththeRESTmanagementAPIprovidedviaourintegrationwithJolokia).

ConfiguringAcceptors

Inordertomakeuseofaparticularprotocol,atransportmustbeconfiguredwiththedesiredprotocolenabled.Thereisawholesectiononconfiguringtransportsthatcanbefoundhere.

ThedefaultconfigurationshippedwiththeActiveMQArtemisdistributioncomeswithanumberofacceptorsalreadydefined,oneforeachoftheaboveprotocolsplusagenericacceptorthatsupportsallprotocols.Toenableprotocolsonaparticularacceptorsimplyaddthe protocolsurlparametertotheacceptorurlwherethevalueisoneormoreprotocols(separatedbycommas).Ifthe protocolsparameterisomittedfromtheurlallprotocolsareenabled.

ThefollowingexampleenablesonlyMQTTonport1883

tcp://localhost:1883?protocols=MQTT

ThefollowingexampleenablesMQTTandAMQPonport5672

tcp://localhost:5672?protocols=MQTT,AMQP

Thefollowingexampleenablesallprotocolson 61616:


48

tcp://localhost:61616

Herearethesupportedprotocolsandtheircorrespondingvalueusedinthe protocolsurlparameter.

Protocol protocolsvalue

Core(Artemis&HornetQnative) CORE

OpenWire(5.xnative) OPENWIRE

AMQP AMQP

MQTT MQTT

STOMP STOMP


49

AMQPApacheActiveMQArtemissupportstheAMQP1.0specification.Bydefaultthereare acceptorelementsconfiguredtoacceptAMQPconnectionsonports 61616and 5672.

SeethegeneralProtocolsandInteroperabilitychapterfordetailsonconfiguringan acceptorforAMQP.

YoucanuseanyAMQP1.0compatibleclients.

Ashortlistincludes:

qpidclients.NETClientsJavascriptNodeJSJavaScriptRHEA...andmanyothers.

ExamplesWehaveafewexamplesaspartoftheArtemisdistribution:

.NET:./examples/protocols/amqp/dotnet

ProtonCPP./examples/protocols/amqp/proton-cpp./examples/protocols/amqp/proton-clustered-cpp

Ruby./examples/protocols/amqp/proton-ruby

Java(UsingtheqpidJMSClient)./examples/protocols/amqp/queue

Interceptors./examples/features/standard/interceptor-amqp./examples/features/standard/broker-plugin

MessageConversions

ThebrokerwillnotperformanymessageconversiontoanyotherprotocolswhensendingAMQPandreceivingAMQP.

HoweverifyouintendyourmessagetobereceivedbyanAMQPJMSClient,youmustfollowtheJMSMappingConventions.IfyousendabodytypethatisnotrecognizedbythisspecificationtheconversionbetweenAMQPandanyotherprotocolwillmakeitaBinaryMessage.Makesureyoufollowtheseconventionsifyouintendtocrossprotocolsorlanguages.Especiallyonthemessagebody.

AcompatibilitysettingallowsaligningthenamingconventionofAMQPqueues(JMSDurableandSharedSubscriptions)withCORE.Forbackwardscompatibilityreasons,youneedtoexplicitlyenablethisviabrokerconfiguration:

amqp-use-core-subscription-naming

true-usequeuenamingconventionthatisalignedwithCORE.false(default)-useoldernamingconvention.

AMQP

50

https://www.oasis-open.org/committees/tc_home.php?wg_abbrev=amqphttps://qpid.apache.org/download.htmlhttps://blogs.apache.org/activemq/entry/using-net-libraries-with-activemqhttps://github.com/noodlefrenzy/node-amqp10https://github.com/grs/rheahttps://www.oasis-open.org/committees/download.php/53086/amqp-bindmap-jms-v1.0-wd05.pdf

Interceptingandchangingmessages

Wedon'trecommendchangingmessagesattheserver'ssideforafewreasons:

AMQPmessagesaremeanttobeimmutableThemessagewon'tbetheoriginalmessagetheusersentAMQPhasthepossibilityofsigningmessages.Thesignaturewouldbebroken.Forperformancereasons.Wetrynottore-encode(orevendecode)messages.

IfregardlesstheserecommendationsyoustillneedandwanttointerceptandchangeAMQPmessages,lookattheaforementionedinterceptorexamples.

AMQPandsecurity

TheApacheActiveMQArtemisServeracceptsthePLAIN,ANONYMOUS,andGSSAPISASLmechanism.Theseareimplementedonthebroker'ssecurityinfrastructure.

AMQPanddestinations

IfanAMQPLinkisdynamicthenatemporaryqueuewillbecreatedandeithertheremotesourceorremotetargetaddresswillbesettothenameofthetemporaryqueue.IftheLinkisnotdynamicthenthetheaddressoftheremotetargetorsourcewillusedforthequeue.Ifthisdoesnotexistthenitwillbeauto-createdifthesettingsallow.

AMQPandMulticastAddresses(Topics)

AlthoughAMQPhasnonotionof"topics"itisstillpossibletotreatAMQPconsumersorreceiversassubscriptionsratherthanjustconsumersonaqueue.Bydefaultanyreceivinglinkthatattachestoanaddressthathasonly multicastenabledwillbetreatedasasubscriptionandacorrespondingsubscriptionqueuewillbecreated.IftheTerminusDurabilityiseitherUNSETTLED_STATEor CONFIGURATIONthenthequeuewillbemadedurable(similartoaJMSdurablesubscription)andgivenanamemadeupfromthecontaineridandthelinkname,somethinglike my-container-id:my-link-name.IftheTerminusDurabilityisconfiguredas NONEthenavolatile multicastqueuewillbecreated.

AMQPandCoordinations-HandlingTransactions

AnAMQPlinkstargetcanalsobeaCoordinator.ACoordinatorisusedtohandletransactions.Ifacoordinatorisusedthentheunderlyingserversessionwillbetransactedandwillbeeitherrolledbackorcommittedviathecoordinator.

Note:

AMQPallowstheuseofmultipletransactionspersession, amqp:multi-txns-per-ssn,howeverinthisversionofApacheActiveMQArtemiswillonlysupportsingletransactionspersession.

AMQPschedulingmessagedelivery

AnAMQPmessagecanprovideschedulinginformationthatcontrolsthetimeinthefuturewhenthemessagewillbedeliveredattheearliest.Thisinformationisprovidedbyaddingamessageannotationtothesentmessage.

Therearetwodifferentmessageannotationsthatcanbeusedtoscheduleamessageforlaterdelivery:

AMQP

51

x-opt-delivery-timeThespecifiedvaluemustbeapositivelongcorrespondingtothetimethemessageshouldbemadeavailablefordelivery(inmilliseconds).

x-opt-delivery-delayThespecifiedvaluemustbeapositivelongcorrespondingtotheamountofmillisecondsafterthebrokerreceivesthegivenmessagebeforeitshouldbemadeavailablefordelivery.

Ifbothannotationsarepresentinthesamemessagethenthebrokerwillpreferthemorespecific x-opt-delivery-timevalue.

ConfiguringAMQPIdleTimeoutItispossibletoconfiguretheAMQPServer'sIDLETimeoutbysettingthepropertyamqpIdleTimeoutinmillisecondsontheacceptor.

ThiswillmaketheservertosendanAMQPframeopentotheclient,withyourconfiguredtimeout/2.

So,ifyouconfiguredyourAMQPIdleTimeouttobe60000,theserverwilltelltheclienttosendframesevery30,000milliseconds.

....;amqpIdleTimeout=;.....

DisablingKeepalivechecks

ifyousetamqpIdleTimeout=0thatwilltellclientstonotsendingkeepalivepacketstowardstheserver.OnthiscaseyouwillrelyonTCPtodeterminewhenthesocketneedstobeclosed.

....;amqpIdleTimeout=0;.....

ThiscontainsarealexampleforconfiguringamqpIdleTimeout:

tcp://0.0.0.0:5672?amqpIdleTimeout=0;tcpSendBufferSize=1048576;tcpReceiveBufferSize=10485

76;protocols=AMQP;useEpoll=true;amqpCredits=1000;amqpMinCredits=300;directDeliver=false;batchDelay=10

AMQP

52

MQTTMQTTisalightweight,clienttoserver,publish/subscribemessagingprotocol.MQTThasbeenspecificallydesignedtoreducetransportoverhead(andthusnetworktraffic)andcodefootprintonclientdevices.ForthisreasonMQTTisideallysuitedtoconstraineddevicessuchassensorsandactuatorsandisquicklybecomingthedefactostandardcommunicationprotocolforIoT.

ApacheActiveMQArtemissupportsMQTTv3.1.1(andalsotheolderv3.1codemessageformat).BydefaultthereareacceptorelementsconfiguredtoacceptMQTTconnectionsonports 61616and 1883.

SeethegeneralProtocolsandInteroperabilitychapterfordetailsonconfiguringan acceptorforMQTT.

ThebestsourceofinformationontheMQTTprotocolisinthe3.1.1specification.

RefertotheMQTTexamplesforalookatsomeofthisfunctionalityinaction.

MQTTQualityofServiceMQTToffers3qualityofservicelevels.

Eachmessage(ortopicsubscription)candefineaqualityofservicethatisassociatedwithit.Thequalityofserviceleveldefinedonatopicisthemaximumlevelaclientiswillingtoaccept.Thequalityofservicelevelonamessageisthedesiredqualityofservicelevelforthismessage.Thebroker

Table of Contents - Apache ActiveMQWritten in Java. Runs on any platform with a Java 8+ runtime, that's everything from Windows desktops to IBM mainframes. Amazing performance. Our

Documents