This version must be installed on [Petals ESB 5.4.0]+ Features The Validation Service-Engine allows to validate and filter Petals messages against an XML Schema. Each configuration of this component embeds an XML Schema (made up of one or several XSD files). When such a configuration (i.e. service, i.e. service-unit) is called, it validates the received message against the XML Schema. Depending on the called operation, the returned message is either a boolean (validate operation) or the received message or a fault (filter operation). filter and validate are the only operations this component supports. This component only acts as service provider, not as a service consumer. In fact, it provides a validation / filtering service (the filtering relies on the validity of the message against the XML Schema). Validation Component overview Recommended usage The Validation component may be used before calling a critical service. It allows to make sure the message to send has the right shape. For some services, this can be useless. For some others though, it can be critical to perform this check. A typical example One typical example would be a service converting the received message as data and manipulating it then (e.g. to insert it into a database). In Petals ESB, that would concern the Petals-BC-SQL component or even the Petals-SE-Talend component. Notice that this last one has a built-in feature to validate received messages against the job's WSDL. Another example could be a service that accesses an EJB. The received message is mapped to a Java object that is about to be manipulated in a JEE container. Making sure the sent message is valid may prevent errors from occurring later in the processing. In a perfect SOA world, this component would be useless. Every service would have a WSDL, and every service consumer would rely on this WSDL to send a message. But this is only good practices. It happens that service consumers do not send the perfect messages. It can be the case with integration use cases (e.g. with an EIP - Enterprise Integration Pattern - or a POJO that consumes a service by generating dynamically the message to send). Before calling this service, you might want to ensure the validity of the built message. An this is where you will use the Validation component. Roughly, the principle looks like if( validationService.validate( MSG )) { criticalService.criticalOperation( MSG ); } else { log( "The message was invalid." ); } Validation and chaining services Following our previous algorithm, it appears that validating or filtering a message only makes sense if this message is going to be sent to another service. That supposes that there is a chaining service, that will first call the validation service, and then call the real target service. Message from the chaining service to the validation / filtering service. Response from the validation / filtering service to the chaining service (the MEP is InOut, always, no matter what the operation is). Message from the chaining service to the real target service. Optional response, depending on the MEP for the second service. This chaining service can be implemented by a POJO (an home made Java Class) or an Enterprise Integration Pattern (EIP). It could also be implemented by a BPEL process, but this latter needs that the WSDL proposed by the Validation component is correct and completed. Note that BPEL can validate by itself the message during its processing, so it may be useless to use the Validation component in some cases. Limitations The validated / filtered content is always the payload from the input message. Do not mistake XML-validation services for interceptors. Neither to validate attached, nor to intercept and validate messages on the fly. Interceptors would better fit this kind of use case.

Table of contents 1 Features 2 Recommended usage 2.1 A typical example 2.2 Validation and chaining services 2.3 Limitations 3 Creating a XML Validation service (Provides mode) 3.1 The "validate" operation 3.2 The "filter" operation 3.3 Service Unit Configuration 3.3.1 Placeholder 3.3.2 CDK parameters defining service provider implementation 3.3.3 CDK parameters driving interceptors 3.3.4 Dedicated configuration 3.3.5 Service unit content 3.3.6 Example 4 Configuring the component 4.1 CDK parameters 4.2 Interception configuration 4.3 Dedicated configuration 5 Business monitoring 5.1 MONIT traces 5.2 Flow tracing activation 6 Monitoring the component 6.1 Using metrics 6.1.1 Common metrics 6.1.2 Dedicated metrics 6.2 Receiving alerts 6.2.1 Common alerts 6.2.2 Dedicated alerts Contributors No contributors found for: authors on selected page(s)

Creating a XML Validation service (Provides mode)

Each Validation service runs on the Petals Validation component.
The Petals Validation component has native operations to invoke. These operations are inherited by the Validation services.
A Validation service cannot add additional operations. It only has the ones of the XSLT component.

This version of the Petals Validation component exposes two operations.

• validate: the received message is validated against a XML-Schema. The service returns a boolean response indicating if the message is valid.
• filter: the received message is validated against a XML-Schema. If the message is valid, this same message is returned. Otherwise, a fault is raised.

The "validate" operation

The fully qualified name of this operation is:

• Name space URI: http://petals.ow2.org/components/validation/version-1
• Local part: validate

This operation only supports the InOut message exchange pattern (MEP).
When invoking this operation, you must call it using its fully qualified name.

Here is the execution flow for this operation:

1. The received message is validated against the XML-Schema embedded by the service.
2. The validation response is wrapped into a message and sent back.

More precisely, if the message is valid, the returned message is:

<!-- The target name space depends on the version of the Validation component -->
<tns:validateResponse xmlns:tns='http://petals.ow2.org/components/validation/version-1'>
     <tns:valid>true</tns:valid>
</tns:validateResponse>

Otherwise, it is:

<!-- The target name space depends on the version of the Validation component -->
<tns:validateResponse xmlns:tns='http://petals.ow2.org/components/validation/version-1'>
     <tns:valid>false</tns:valid>
     <tns:comment>The reason explaining why it is invalid.</tns:comment>
</tns:validateResponse>

The "filter" operation

The fully qualified name of this operation is:

• Name space URI: http://petals.ow2.org/components/validation/version-1
• Local part: filter

This operation only supports the InOut message exchange pattern (MEP).
When invoking this operation, you must call it using its fully qualified name.

Here is the execution flow for this operation:

1. The received message is validated against the XML-Schema embedded by the service.
2. If the message is valid, this same message is sent back. Otherwise, a fault is raised.

<!-- The target name space depends on the version of the Validation component -->
<tns:validationFault xmlns:tns='http://petals.ow2.org/components/validation/version-1'>
     <tns:message>The fault message.</tns:message>
<tns:validationFault>

If the operation is invalid (i.e. is neither validate, nor filter), then filter is the operation by default.

Service Unit Configuration

All needed information must be defined in the service-unit JBI descriptor. This JBI descriptor is configured through parameters divided in following groups:

• JBI parameters that defines the service provider identification,
• CDK parameters that are parameters driving the service provider implementation at CDK layer,
• CDK interceptor parameters that are parameters driving interceptors at CDK layer,
• Dedicated parameters that are parameters driving the service provider implementation at component layer.

A JBI descriptor for an Validation service-unit can only define one provides block.

Placeholder

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.

CDK parameters defining service provider implementation

The following parameters correspond to the CDK configuration of the service provider implementation.

The service provider is defined into the section 'provides' of the JBI descriptor, containing:

CDK parameters driving interceptors

The following parameters drive interceptors at CDK layer.

Interceptors can be defined to inject some post or pre-processing in the service provider processing or service consumer processing.

Using interceptor is very sensitive and must be manipulated only by power users. A 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"?>
<jbi:jbi xmlns:jbi="http://java.sun.com/xml/ns/jbi" xmlns:petalsCDK="http://petals.ow2.org/components/extensions/version-5">
   <jbi:services>
      <jbi:provides|consumes>
         <!--...-->
         <petalsCDK:su-interceptors>
            <petalsCDK:send>
               <petalsCDK:interceptor name="myInterceptorName">
                  <petalsCDK:param name="myParamName">myParamValue</petalsCDK:param>
                  <petalsCDK:param name="myParamName2">myParamValue2</petalsCDK:param>
               </petalsCDK:interceptor>
            </petalsCDK:send>
            <petalsCDK:accept>
               <petalsCDK:interceptor name="myInterceptorName">
                  <petalsCDK:param name="myParamName">myParamValue</petalsCDK:param>
               </petalsCDK:interceptor>
            </petalsCDK:accept>
            <petalsCDK:send-response>
               <petalsCDK:Interceptor name="myInterceptorName">
                  <petalsCDK:param name="myParamName">myParamValue</petalsCDK:param>
               </petalsCDK:Interceptor>
            </petalsCDK:send-response>
            <petalsCDK:accept-response>
               <petalsCDK:Interceptor name="myInterceptorName">
                  <petalsCDK:param name="myParamName">myParamValue</petalsCDK:param>
               </petalsCDK:Interceptor>
            </petalsCDK:accept-response>
         </petalsCDK:su-interceptors>
         <!--...-->
      </jbi:provides|consumes>
      <!--...-->
   </jbi:services>
</jbi:jbi>

Dedicated configuration

The following parameters correspond to the component specific configuration of the service provider implementation.

Service unit content

The service unit has to contain the following elements, packaged in the archive:

• the META-INF/jbi.xml descriptor file as described above,
• it is also highly recommended to provide a WSDL description for service provider embedded in the service-unit. The service provider contract must implement the interface "{http://petals.ow2.org/components/validation/version-1}ValidationInterface" defined in the abstract WSDL 'ValidationInterface.wsdl' available as resource in the component archive,
• the XML Schema files.

su-xslt-TransformationName-provide.zip
  + META-INF
    - jbi.xml (as defined above)
  - XsltService.wsdl (recommended)
  - myfile.xsd (required)
  - myfile2.xsd (required if myfile2.xsd is imported in myfile.xsd)

Example

An example of a Service Unit descriptor to provide an validation service:

<?xml version="1.0" encoding="UTF-8"?>
<jbi:jbi version="1.0"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:jbi="http://java.sun.com/xml/ns/jbi"
	xmlns:petalsCDK="http://petals.ow2.org/components/extensions/version-5"
	xmlns:validation="http://petals.ow2.org/components/validation/version-1"
	xmlns:serviceNs="http://petals.ow2.org/simpletransformation">

 <jbi:services binding-component="false">
	<jbi:provides
		interface-name="validation:ValidationInterface"
		service-name="serviceNs:ValidationService"
		endpoint-name="ValidationEndpoint">

   <!-- WSDL file -->
   <petalsCDK:wsdl>your optional description wsdl file.wsdl</petalsCDK:wsdl>

   <!-- Validation specific fields -->
   <validation:schema>schema.xsd</validation:schema>
  </jbi:provides>
 </jbi:services>
</jbi:jbi>

Configuring the component

The component can be configured through the parameters of its JBI descriptor file. These parameters are divided in following groups:

• JBI parameters that have not to be changed otherwise the component will not work,
• CDK parameters that are parameters driving the processing of the CDK layer,
• Dedicated parameters that are parameters specific to this component.

Caution: The component requires the right JDBC Shared Libraries to communicate with your databases. Please install first valid Shared Libraries containing your database JDBC drivers. Then you can configure your component by using PETALS Maven plugin with the goal jbi:configure or the PETALS Ant task petals-configure-component.

CDK parameters

The component configuration includes the configuration of the CDK. The following parameters correspond to the CDK configuration.

• 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.

Interception configuration

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 manipulated only by power users. A 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"?>
<jbi:jbi xmlns:jbi="http://java.sun.com/xml/ns/jbi" xmlns:petalsCDK="http://petals.ow2.org/components/extensions/version-5" ...>
   <jbi:component>
      <!--...-->
      <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>
      <!--...-->
   </jbi:component>
</jbi:jbi>

Dedicated configuration

No dedicated configuration parameter is available.

Business monitoring

MONIT traces

Each service provider implemented is able to log MONIT traces with following information:

• on service provider invocation, when receiving an incoming request, with following attributes:
  • traceCode set to provideFlowStepBegin,
  • flowInstanceId set to the flow instance identifier retrieved from the incoming request,
  • flowStepId set to an UUID value,
  • flowStepInterfaceName set to the service provider interface name,
  • flowStepServiceName set to the service provider service name,
  • flowStepOperationName set to the operation of the invoked service provider,
  • flowStepEndpointName set to the service provider endpoint name,
  • flowPreviousStepId set to the step identifier of the previous step, retrieved from the incoming request.
• on service provider termination, when returning the outgoing response, with following attributes:
  • traceCode set to provideFlowStepEnd or provideFlowStepFailure,
  • flowInstanceId set to the flow instance identifier retrieved from the incoming request,
  • flowStepId set to the flow step identifier defined on incoming request receipt.

Flow tracing activation

The flow tracing (ie. MONIT traces generation) is defined according to the property 'org.ow2.petals.monitoring.business.activate-flow-tracing' of the incoming JBI request. If the property does not exist, the parameter activate-flow-tracing of the service provider definition will be inspected. If no parameter is defined at service provider level, the component configuration parameter 'activate-flow-tracing' is used. Finally, by default, the flow tracing is enabled.

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:

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

Dedicated alerts

No dedicated alert is available.