Petals-BC-JMS 3.5.0+

This version must be installed on [Petals ESB 5.4.0]+

Features

The Petals JMS component can be used to interact with an external JMS application or server (through a queue or a topic).
When used with the provider role, it allows to post TextMessages to a JMS queue or topic.
When used with the consumer role, it allows to read messages from a queue or receive messages posted on a given topic.

Contributors
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Recommended Usage

This component should be used whenever interactions with a JMS server or application is required.
This component needs a driver (also called a shared library in Petals) so that Petals can interact with the JMS application. This shared library generally contains the JNDI classes, as a JNDI is used to enable communications between both servers.


  • Only JMS TextMessage are recognized by the Petals JMS component.
  • With the version 3.0, only XML messages can be published and received from a JMS application.
  • In Petals, the invoked service operation is mapped to the operation property of the JMS TextMessage (both in consumming and providing mode).


If you use ActiveMQ as a JMS server, be careful.
ActiveMQ (AMQ) does not provide a complete JNDI server, which results in limitations with Petals.
  • There is no problem with AMQ if you rely on dynamic queues and topics (ActiveMQ's specific mechnaism).
  • For static queues and topics, there are two solutions.
    • Use a separate JNDI server and configure both Petals and ActiveMQ to use it.
    • Rely on AMQ's limited JNDI but upgrade the Petals JMS component (meaning it has to be patched).
      The patch consist in putting additional properties in the initial context. See this discussion for more information.

Sending a message to a JMS Queue

This use case is similar to publishing a message on a JMS topic.

Publishing a message to a JMS Topic

Usage

To do that with Petals, you have to create a service associated with the Petals JMS component.
This is achieved by creating a service unit whose jbi.xml contains a provides section. When deployed in Petals, the Petals JMS component will emulate a service. When this service is invoked, the received message will be posted as a TextMessage on the topic defined in the service unit configuration.

  • All the MEP are allowed. However, due to the JMS paradigm, all exchanges are processed like InOnly exchanges. For exemple, an InOut exchange returns a default message if the JMS message is sent succesfully.
  • The external Queue or Topic referenced by the Service Unit does not have to be available before the Service Unit is started. But the JNDI server where Queue or Topic are registered must be available before the Service Unit deployment.
  • Properties from the Petals message are automatically converted to JMS message properties.

Configuration

Service Unit descriptor

The Service Unit descriptor file ( jbi.xml ) looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<!-- 
	JBI descriptor for the Petals' "petals-bc-jms" component (JMS).
	Originally created for the version 3.1 of the component.
 -->
<jbi:jbi version="1.0" 
	xmlns:generatedNs="http://petals.ow2.org"
	xmlns:jbi="http://java.sun.com/xml/ns/jbi"
	xmlns:jms="http://petals.ow2.org/components/jms/version-3"
	xmlns:petalsCDK="http://petals.ow2.org/components/extensions/version-5"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
	
	<!-- Import a Service into Petals or Expose a Petals Service => use a BC. -->
	<jbi:services binding-component="true">
	
		<!-- Import a Service into Petals => provides a Service. -->
		<jbi:provides 		
			interface-name="generatedNs:itf"
			service-name="generatedNs:srv"
			endpoint-name="srvEndpoint">
	
			<!-- CDK specific elements -->
			<petalsCDK:timeout>30000</petalsCDK:timeout>
			<petalsCDK:validate-wsdl>true</petalsCDK:validate-wsdl>
			<petalsCDK:forward-security-subject>false</petalsCDK:forward-security-subject>
			<petalsCDK:forward-message-properties>false</petalsCDK:forward-message-properties>
			<petalsCDK:forward-attachments>false</petalsCDK:forward-attachments>
			<petalsCDK:wsdl xsi:nil="true" />
		
			<!-- Component specific elements -->	
			<jms:jndi-provider-url>tcp://localhost:61616</jms:jndi-provider-url>
			<jms:jndi-initial-context-factory>org.apache.activemq.jndi.ActiveMQInitialContextFactory</jms:jndi-initial-context-factory>
			<jms:jndi-destination-name>dynamicQueues/PetalsQueue</jms:jndi-destination-name>
			<jms:jndi-connection-factory>QueueConnectionFactory</jms:jndi-connection-factory>
			<jms:transacted>false</jms:transacted>
			<jms:max-active>10</jms:max-active>
			<jms:max-idle>5</jms:max-idle>
			<jms:max-wait>10000</jms:max-wait>
			<jms:time-between-eviction-runs-millis>30000</jms:time-between-eviction-runs-millis>
			<jms:min-evictable-idle-time-millis>600000</jms:min-evictable-idle-time-millis>
			<jms:test-while-idle>true</jms:test-while-idle>			
		</jbi:provides>
	</jbi:services>
</jbi:jbi>

A placeholder is a specific value that is resolved at runtime against a property available in the property file set at component level. It is mainly used in the service unit JBI descriptor to be able to configure your service providers and/or your service consumers.

<service-unit-parameter>${dgfip.quotient-familial.base-url}</service-unit-parameter>

Its syntax is: '${placeholder-name[:default-value]}',

  • if no property with name 'placeholder-name' exists in the component property file, the default value 'default-value' is used. If no default value is defined, the literal value '${placeholder-name}' is used,
  • if a placeholder name must contain the character ':' (colon), it must be escaped by the character '\', example: ${placeholder-name-with-\:-colon:default-value}',
  • if a placeholder default value must contain the character ':' (colon), it must be escaped by the character '\', example: ${placeholder-name:default-value-with-\:-colon}'.
  • the escape character can be escaped by itself.

Placeholders are not supported for each service unit parameter, check your documentation before to use them.
It is also possible to change a placeholder value at runtime reloading the component property file. It is not sufficient, the parameter associated to the placeholder must be changeable at runtime. So check component documentation to know that.

Service Unit attributes to provide services

Parameter Description Default Required
provides Name of the JBI service that will be activated to expose the JMS destination into the JBI environment. Interface (qname), service (qname) and endpoint (string) name are required. - Yes
address Address composed of the URL provider (JNDI access) - Yes
destination-name The JMS destination name where messages will be sent (Queue or Topic JNDI name) - Yes
initial-context-factory The initial-context-factory class name, used to create an InitalContext. - Yes
connection-factory name of the JMS ConnectionFactory registered. - Yes
user User name to access the JMS Destination. "" Yes
password Password to access the JMS Destination. "" Yes
transacted JMS communication transacted mode. true or false. false Yes
max-active Controls the maximum number of JMS connections that can be borrowed from the pool at one time. When non-positive, there is no limit to the number of connections that may be active at one time. When maxActive is exceeded, the pool is said to be exhausted. 10 No
max-idle Controls the maximum number of JMS connections that can sit idle in the pool at any time. When negative, there is no limit to the number of connections that may be idle at one time. 5 No
max-wait If a positive maxWait value is supplied, the JMS component will wait for at most that many milliseconds to retrieve an available JMS connection. If maxWait is non-positive, the component will wait indefinitely. 10000 No
time-between-eviction-runs-millis Indicates how long the eviction thread should sleep before "runs" of examining idle connections. When non-positive, no eviction thread will
be launched.
10000 No
min-evictable-idle-time-millis Specifies the minimum amount of time that a connection may sit idle in the pool before it is eligable for eviction due to idle time. When non-positive,
no connections will be dropped from the pool due to idle time alone.
2000 No
test-while-idle Indicates whether or not idle connections should be validated. Connections that fail to validate will be dropped from the pool. true No

Advanced configuration of Service Unit (provides elements)

Parameter Description Default Required
wsdl Path to a wsdl file describing services and operations offered by an endpoint activated by the SU. This extension is only usable with provides fields.
The path can be a url "http" or "file" or relative to the r oot directory of the SU archive. Ex: "file:///user/ofabre/test.wsdl" or "/WSDL/test.wsdl".
If no wsdl path is specified, a simplified description will automaticaly be written by the CF.
- No

Service Unit content

The Service Unit has to contain the following elements, packaged in an archive:

  • The META-INF/jbi.xml descriptor file, has described above
  • An optional WSDL file describing the related service.
service-unit.zip
+ META-INF
    - jbi.xml (as defined above)
    - service.wsdl (optional)

Consuming a message from a JMS Queue

This use case is similar to subscribing to a JMS topic.

Subscribing to a JMS Topic

Consumes a JBI service on JMS message

Usage

The Petals JMS component can listen to an external JMS Queue or JMS Topic.
When it receives a message, it creates a Petals message and sends to a Petals service (we say that the component consumes the JBI service). This service is specified in the Service Unit.

  • All MEP are allowed. But, due to the JMS paradigm, all exchanges are processed like InOnly exchanges.
  • The external Queue or Topic referenced by the Service Unit has to be available before you start the Service Unit.

Configuration

Service Unit Descriptor

The Service Unit descriptor file ( jbi.xml ) looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<!-- 
	JBI descriptor for the Petals' "petals-bc-jms" component (JMS).
	Originally created for the version 3.1 of the component.
 -->
<jbi:jbi version="1.0" 
	xmlns:generatedNs="http://petals.ow2.org"
	xmlns:jbi="http://java.sun.com/xml/ns/jbi"
	xmlns:jms="http://petals.ow2.org/components/jms/version-3"
	xmlns:petalsCDK="http://petals.ow2.org/components/extensions/version-5"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
	
	<!-- Import a Service into Petals or Expose a Petals Service => use a BC. -->
	<jbi:services binding-component="true">
	
		<!-- Expose a Petals Service => consumes a Service. -->
		<jbi:consumes
			interface-name="generatedNs:itf"
			service-name="generatedNs:srv"
			endpoint-name="srvEndpoint">
	
			<!-- CDK specific elements -->
			<petalsCDK:timeout>30000</petalsCDK:timeout>
			<petalsCDK:operation xmlns:wedontcareNs="http://something">wedontcareNs:wedontcare</petalsCDK:operation>
			<petalsCDK:mep>InOnly</petalsCDK:mep>
		
			<!-- Component specific elements -->	
			<jms:jndi-provider-url>tcp://localhost:61616</jms:jndi-provider-url>
			<jms:jndi-initial-context-factory>org.apache.activemq.jndi.ActiveMQInitialContextFactory</jms:jndi-initial-context-factory>
			<jms:jndi-destination-name>dynamicTopics/PetalsTopic</jms:jndi-destination-name>
			<jms:jndi-connection-factory>ConnectionFactory</jms:jndi-connection-factory>
			<jms:transacted>false</jms:transacted>
		</jbi:consumes>
	</jbi:services>
</jbi:jbi>

A placeholder is a specific value that is resolved at runtime against a property available in the property file set at component level. It is mainly used in the service unit JBI descriptor to be able to configure your service providers and/or your service consumers.

<service-unit-parameter>${dgfip.quotient-familial.base-url}</service-unit-parameter>

Its syntax is: '${placeholder-name[:default-value]}',

  • if no property with name 'placeholder-name' exists in the component property file, the default value 'default-value' is used. If no default value is defined, the literal value '${placeholder-name}' is used,
  • if a placeholder name must contain the character ':' (colon), it must be escaped by the character '\', example: ${placeholder-name-with-\:-colon:default-value}',
  • if a placeholder default value must contain the character ':' (colon), it must be escaped by the character '\', example: ${placeholder-name:default-value-with-\:-colon}'.
  • the escape character can be escaped by itself.

Placeholders are not supported for each service unit parameter, check your documentation before to use them.
It is also possible to change a placeholder value at runtime reloading the component property file. It is not sufficient, the parameter associated to the placeholder must be changeable at runtime. So check component documentation to know that.

Service Unit attributes to consume services

Parameter Description Default Required
consumes Name of the JBI service that will be called into the JBI environment. When a JMS message is received. Only the interface (qname) name can be provided (the container will choose a ServiceEndpoint for this interface), or you can only set service (qname) and endpoint (string) names, without the interface name. - Yes
address Address composed of the URL provider (JNDI access) and the destination name to listen to - Yes
destination-name The JMS destination name where messages will be sent (Queue or Topic JNDI name) - Yes
initial-context-factory The initial-context-factory class name, used to create an InitalContext. - Yes
connection-factory name of the JMS ConnectionFactory registered. - Yes
user User name to access the JMS Destination. "" Yes
password Password to access the JMS Destination. "" Yes
transacted JMS communication transacted mode. true or false. false No
operation JMS operation property. - Yes

Extra attributes:

Advanced configuration of Service Unit (consumes elements)

Parameter Description Default Required
mep Message exchange pattern abbreviation. This parameter can be used in conjunction with a method of the Listeners: createMessageExchange(Extensions extensions). This method returns
a MessageExchange corresponding to the type of the specified pattern.
Admitted values are: InOnly, RobustInOnly, InOptionalOut, InOut.
- Yes
operation Operation to call on a service. This parameter can be used in conjuntcion
with the sendXXX methods of the Listeners. If no operation is specified in the MessageExchange to send, this parameter will be used.
- Yes
timeout Timeout in milliseconds in a synchroneous send. This parameter can be used in conjunction with the sendSync(MessageExchange exchange) method of the Listeners. With this, a synchroneous send is done with this timeout value.
0 for no timeout.
int number >= 0 for a timeout.
- No
operation JMS operation property. - Yes

Service Unit content

The Service Unit has to contain the following elements, packaged in an archive:

  • The META-INF/jbi.xml descriptor file, has described above
service-unit.zip
+ META-INF
    - jbi.xml (as defined above)

Component Configuration

Configuration of the component, CDK part

Parameter Description Default Scope
acceptor-pool-size The size of the thread pool used to accept Message Exchanges from the NMR. Once a message is accepted, its processing is delegated to the processor pool thread. 1
Runtime
acceptor-retry-number Number of tries to submit a message exchange to a processor for processing before to declare that it cannot be processed. 40
Installation
acceptor-retry-wait Base duration, in milliseconds, to wait between two processing submission tries. At each try, the new duration is the previous one plus this base duration. 250
Installation
acceptor-stop-max-wait The max duration (in milliseconds) before, on component stop, each acceptor is stopped by force. 500
Runtime
processor-pool-size The size of the thread pool used to process Message Exchanges. Once a message is accepted, its processing is delegated to one of the thread of this pool. 10 Runtime
processor-max-pool-size The maximum size of the thread pool used to process Message Exchanges. The difference between this size and the processor-pool-size represents the dynamic threads that can be created and destroyed during overhead processing time.
50
Runtime
processor-keep-alive-time When the number of processors is greater than the core, this is the maximum time that excess idle processors will wait for new tasks before terminating, in seconds.
300
Runtime
processor-stop-max-wait The max duration (in milliseconds) of message exchange processing on stop phase (for all processors).
15000
Runtime
time-beetween-async-cleaner-runs The time (in milliseconds) between two runs of the asynchronous message exchange cleaner.
2000
Installation
properties-file Name of the file containing properties used as reference by other parameters. Parameters reference the property name using a placeholder in the following pattern ${myPropertyName}. At runtime, the expression is replaced by the value of the property.

The properties file can be reloaded using the JMX API of the component. The runtime configuration MBean provides an operation to reload these place holders. Check the service unit parameters that support this reloading.

The value of this parameter is :
  • an URL
  • a file relative to the PEtALS installation path
  • an absolute file path
  • an empty value to stipulate a non-using file.
- Installation
monitoring-sampling-period Period, in seconds, of a sample used by response time probes of the monitoring feature.
300
Installation

Definition of CDK parameter scope :

  • Installation: The parameter can be set during the installation of the component, by using the installation MBean (see JBI specifications for details about the installation sequence). If the parameter is optional and has not been defined during the development of the component, it is not available at installation time.
  • Runtime: The paramater can be set during the installation of the component and during runtime. The runtime configuration can be changed using the CDK custom MBean named RuntimeConfiguration. If the parameter is optional and has not been defined during the development of the component, it is not available at installation and runtime times.

Interceptor

Interceptors can be defined to inject some post or pre processing in the component during service processing.

Using interceptor is very sensitive and must be manipulate only by power users. An non properly coded interceptor engaged in a component can lead to uncontrolled behaviors, out of the standard process.

Example of an interceptor configuration:

<?xml version="1.0" encoding="UTF-8"?>
<!--...-->
<petalsCDK:component-interceptors>
  <petalsCDK:interceptor active="true" class="org.ow2.petals.myInterceptor" name="myInterceptorName">
    <petalsCDK:param name="myParamName">myParamValue</petalsCDK:param>
    <petalsCDK:param name="myParamName2">myParamValue2</petalsCDK:param>
  </petalsCDK:interceptor>
</petalsCDK:component-interceptors>
<!--...-->

Interceptors configuration for Component (CDK)

Parameter Description Default Required
interceptor - class Name of the interceptor class to implement. This class must extend the abstract class org.ow2.petals.component.common.interceptor.Interceptor. This class must be loadable from the component classloader, or in a dependent Shared Library classloader. - Yes
interceptor - name Logical name of the interceptor instance. It can be referenced to add extended parameters by a SU Interceptor configuration. - Yes
interceptor - active If true, the Interceptor instance is activated for every SU deployed on the component.
If false, the Interceptor can be activated:
-by the InterceptorManager Mbean at runtime, to activate the interceptor for every deployed SU.
-by a SU configuration
- Yes
param[] - name The name of the parameter to use for the interceptor. - No
param[] The value of the parameter to use for the interceptor. - No

Monitoring the component

Using metrics

Several probes providing metrics are included in the component, and are available through the JMX MBean 'org.ow2.petals:type=custom,name=monitoring_<component-id>', where <component-id> is the unique JBI identifier of the component.

Common metrics

The following metrics are provided through the Petals CDK, and are common to all components:

Metrics, as MBean attribute Description Detail of the value Configurable
MessageExchangeAcceptorThreadPoolMaxSize The maximum number of threads of the message exchange acceptor thread pool integer value, since the last startup of the component yes, through acceptor-pool-size
MessageExchangeAcceptorThreadPoolCurrentSize The current number of threads of the message exchange acceptor thread pool. Should be always equals to MessageExchangeAcceptorThreadPoolMaxSize. instant integer value no
MessageExchangeAcceptorCurrentWorking The current number of working message exchange acceptors. instant long value no
MessageExchangeAcceptorMaxWorking The max number of working message exchange acceptors. long value, since the last startup of the component no
MessageExchangeAcceptorAbsoluteDurations The aggregated durations of the working message exchange acceptors since the last startup of the component. n-tuple value containing, in nanosecond:
  • the maximum duration,
  • the average duration,
  • the minimum duration.
no
MessageExchangeAcceptorRelativeDurations The aggregated durations of the working message exchange acceptors on the last sample. n-tuple value containing, in nanosecond:
  • the maximum duration,
  • the average duration,
  • the minimum duration,
  • the 10-percentile duration (10% of the durations are lesser than this value),
  • the 50-percentile duration (50% of the durations are lesser than this value),
  • the 90-percentile duration (90% of the durations are upper than this value).
no
MessageExchangeProcessorAbsoluteDurations The aggregated durations of the working message exchange processor since the last startup of the component. n-tuple value containing, in milliseconds:
  • the maximum duration,
  • the average duration,
  • the minimum duration.
no
MessageExchangeProcessorRelativeDurations The aggregated durations of the working message exchange processor on the last sample. n-tuple value containing, in milliseconds:
  • the maximum duration,
  • the average duration,
  • the minimum duration,
  • the 10-percentile duration (10% of the durations are lesser than this value),
  • the 50-percentile duration (50% of the durations are lesser than this value),
  • the 90-percentile duration (90% of the durations are upper than this value).
no
MessageExchangeProcessorThreadPoolActiveThreadsCurrent The current number of active threads of the message exchange processor thread pool instant integer value no
MessageExchangeProcessorThreadPoolActiveThreadsMax The maximum number of threads of the message exchange processor thread pool that was active integer value, since the last startup of the component no
MessageExchangeProcessorThreadPoolIdleThreadsCurrent The current number of idle threads of the message exchange processor thread pool instant integer value no
MessageExchangeProcessorThreadPoolIdleThreadsMax The maximum number of threads of the message exchange processor thread pool that was idle integer value, since the last startup of the component no
MessageExchangeProcessorThreadPoolMaxSize The maximum size, in threads, of the message exchange processor thread pool instant integer value yes, through http-thread-pool-size-max
MessageExchangeProcessorThreadPoolMinSize The minimum size, in threads, of the message exchange processor thread pool instant integer value yes, through http-thread-pool-size-min
MessageExchangeProcessorThreadPoolQueuedRequestsCurrent The current number of enqueued requests waiting to be processed by the message exchange processor thread pool instant integer value no
MessageExchangeProcessorThreadPoolQueuedRequestsMax The maximum number of enqueued requests waiting to be processed by the message exchange processor thread pool since the last startup of the component instant integer value no
ServiceProviderInvocations The number of service provider invocations grouped by:
  • interface name, as QName, the invoked service provider,
  • service name, as QName, the invoked service provider,
  • invoked operation, as QName,
  • message exchange pattern,
  • and execution status (PENDING, ERROR, FAULT, SUCCEEDED).
integer counter value since the last startup of the component no
ServiceProviderInvocationsResponseTimeAbs The aggregated response times of the service provider invocations since the last startup of the component grouped by:
  • interface name, as QName, the invoked service provider,
  • service name, as QName, the invoked service provider,
  • invoked operation, as QName,
  • message exchange pattern,
  • and execution status (PENDING, ERROR, FAULT, SUCCEEDED).
n-tuple value containing, in millisecond:
  • the maximum response time,
  • the average response time,
  • the minimum response time.
no
ServiceProviderInvocationsResponseTimeRel The aggregated response times of the service provider invocations on the last sample, grouped by:
  • interface name, as QName, the invoked service provider,
  • service name, as QName, the invoked service provider,
  • invoked operation, as QName,
  • message exchange pattern,
  • and execution status (PENDING, ERROR, FAULT, SUCCEEDED).
n-tuple value containing, in millisecond:
  • the maximum response time,
  • the average response time,
  • the minimum response time,
  • the 10-percentile response time (10% of the response times are lesser than this value),
  • the 50-percentile response time (50% of the response times are lesser than this value),
  • the 90-percentile response time (90% of the response times are lesser than this value).
no

Dedicated metrics

No dedicated metric is available.

Receiving alerts

Several alerts are notified by the component through notification of the JMX MBean 'org.ow2.petals:type=custom,name=monitoring_<component-id>', where <component-id> is the unique JBI identifier of the component.

To integrate these alerts with Nagios, see Receiving Petals ESB defects in Nagios.

Common alerts

Defect JMX Notification
A message exchange acceptor thread is dead
  • type: org.ow2.petals.component.framework.process.message.acceptor.pool.thread.dead
  • no user data
No more thread is available in the message exchange acceptor thread pool
  • type: org.ow2.petals.component.framework.process.message.acceptor.pool.exhausted
  • no user data
No more thread is available to run a message exchange processor
  • type: org.ow2.petals.component.framework.process.message.processor.thread.pool.exhausted
  • no user data

Dedicated alerts

No dedicated alert is available.

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