Petals Documentation > Petals ESB > Petals Components > Components User Guide > Petals-BC-REST > Petals-BC-REST 1.0.1+

Petals-BC-REST 1.0.1+

This version must be installed on Petals ESB 5.0.2+

Feature

The REST component is a Binding Component (BC) which enables to interact with external RESTful Web Services and to expose JBI services as RESTful Web Services.

In provider role, when a JBI MessageExchange is sent to a ServiceEndpoint (mapped to a Web Service), it is transformed into a REST message and sent to the linked external Web Service. In consumer role, when a REST message is received on an exposed Web Service, it is transformed into a JBI MessageExchange and sent to the corresponding JBI ServiceEndpoint.

The REST component is based on Jersey and Axis2 (TBD). It provides the following features:

  • Expose Restful Web Services as JBI Services
  • Expose Restful Web Services as JBI Services using a WADL (TBC)
  • Expose Restful Web Services as JBI Services using a WSDL 2.0 (TBC)
  • Expose JBI Services as Restful Web Services
REST is a style of software architecture not a standard. If you want more details about REST, you can consult the Wikipedia page: http://en.wikipedia.org/wiki/Representational_State_Transfer
Table of contents
Contributors

Exposing an external Restful Web Service as a JBI service endpoint

In provide mode, the component exposes an external Web Service in the JBI environment to send REST requests to the external Web Service.

Usage

The petals-bc-rest component can expose an external Web Service as a JBI service endpoint by deploying a Service Unit on it:

Provides an external Web Service as a JBI service

When a message is received on a REST linked endpoint from the JBI environment, it is transformed into a REST message and sent to the Web Service.

The REST request is created like this:

  • The REST URI is created from the address extension, the JBI operation and JBI message content (The JBI message content must contains the information about the path, the matrix and query parameters)
  • The HTTP body is created differently according the HTTP method to used:
    • GET/DELETE: There is no HTTP body
    • POST: The HTTP body is also created differently according the JBI message content:
      • The JBI message content contains only a reference to a JBI attachment: The HTTP body is created from a JBI attachment (binary data)
      • The JBI message content does not contains a reference to a JBI attachment: The HTTP body is created from the JBI message content (form parameters)
    • PUT: The HTTP body is created from a JBI attachment
  • The headers present in the protocol header JBI message property are added to the HTTP headers.

For example the following JBI message:






produces the URI http://weather.yahooapis.com/....



The external Web Service is called and the REST response is processed and returned to the JBI environment.



The REST response is transformed into a JBI message like this:


    
	
  • In case of error (HTTP status different from 20x) a JBI fault is created.
    • 
	
  • The JBI message content and attachment are created differently according the Content-Type HTTP header:
	
      
		
    • Non XML content types: The JBI message content is a reference (cf SOAP) to a JBI attachment which contains the HTTP body
      • 
		
    • XML content types: The JBI message content is created from the HTTP body (there is no JBI attachment created)
      • 
	
    
	
    • 
	
  • The HTTP headers are added to the protocol header JBI message property
    • 






With no description of the RESTful Web Service



The address of the RESTful Web Service is defined in the address extension of the deployed Service Unit.

The HTTP method is defined in the http-method SU extension.



With a WADL



The address of the RESTful Web Service is found in the WADL.

The REST operation corresponding to the JBI operation is found in the WADL.

The HTTP method is defined in the WADL for the operation.



With a WSDL 2.0



The address of the RESTful Web Service is found in the WSDL 2.0.

The REST operation corresponding to the JBI operation is found in the WSDL 2.0.

The HTTP method is defined in the WSDL 2.0 for the operation.



Configuration



Configuration of a Service Unit to provide a service (JBI)











 Parameter 
 Description 
 		
 Default 
 		
 Required 




 provides 
 Describe the JBI service that will be exposed into the JBI bus. Interface (QName), Service (QName) and Endpoint (String) attributes are required. 
 - 
 Yes 











Configuration of a Service Unit to provide a service (CDK)











 Parameter 
 Description
 		
 Default
 		
 Required
 		




 timeout 
 Timeout in milliseconds of a synchronous send. This parameter is used by the method sendSync (Exchange exchange) proposes by the CDK Listeners classes. 

Set it to 0 for an infinite timeout. 		
 30000 
 No 




 exchange-properties 
 This sections defines the list of properties to set to the JBI exchange when processing a service. 
 - 
 No 




 message-properties 
 This sections defines the list of properties to set to the JBI message when processing a service. 
 - 
 No 




 validate-wsdl 
 Activate the validation of the WSDL when deploying a service unit. 
 true 
 No 




 wsdl 
 		
 Path to the WSDL document describing services and operations exposed by the provided JBI endpoints defined in the SU. 

The value of this parameter is : 


    
	
  • an URL
    • 
	
  • a file relative to the root of the SU package 
    
If not specified, a basic WSDL description is automaticaly provided by the CDK. 
    • 



 - 
 No 




 forward-attachments 
 		
 Defines if attachment will be forwarded from IN message to OUT message. 
 		
 false 
 No 




 forward-message-properties 
 		
 Defines if the message properties will be forwarded from IN message to OUT message. 
 false 
 No 




 forward-security-subject 
 		
 Defines if the security subject will be forwarded from IN message to OUT message. 
 false 
 No 













Service Unit attributes to provide services











 Attribute 
 Description 
 Default value 
 Required 




 address 
 Address of the external Web Service to send JBI messages to. 
 
 
Yes*

 		




 http-method 
 HTTP method to use. 



Possible values are: GET for the HTTP method GET, POST for the HTTP   method POST, PUT for the HTTP method PUT and DELETE for the HTTP method   DELETE. 
 		
 
 
Yes*

 		




 wadl 
 WADL which defines the partner service 
 
 
Yes*

 		




 wsdl2 
 WSDL2 which defines the partner service 
 
 
Yes*

 		











*Either address and http-method extensions or wadl or wsdl2 must be present in a specific SU.



Service Unit descriptor



The service unit is configurable via its extensions in the jbi.xml file:









Service Unit content



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


    
	
  • The META-INF/jbi.xml descriptor file as described above,
    • 
	
  • An optional imported WADL/WSDL 2.0 file describing the partner service
    • 






Exposing an internal JBI service endpoint as a RESTful Web Service



In consumer mode, the component exposes an internal JBI service outside the bus to transfer incoming REST requests to the internal service.



Usage



The petals-bc-rest component can listen incoming REST messages and send messages to a JBI service endpoint by deploying a Service Unit on it. The component consumes the JBI service:






Consumes a JBI service on a REST message




The service-name Service Unit extension value will be used as service name.



When a REST message is handled by the component, it is transformed into a JBI Message and sent to the JBI service endpoint configured in the Service Unit.



The JBI message is created like this:


    
	
  • The JBI operation is created differently from the operation present in the REST URI operation
    • 
	
  • The JBI message content is created according to the HTTP method of the incoming REST request:
	
      
		
    • GET: The JBI message content is created from the REST URI path and parameters
      • 
		
    • POST: The JBI message content is also created differently according the Content-Type HTTP header:
		
        
			
      • Non XML content types: The JBI message content is a reference (cf SOAP) to a JBI attachment which contains the HTTP body
        • 
			
      • XML content types: The JBI message content is created from the HTTP body (there is no JBI attachment created)
        • 
		
      
		
      • 
		
    • PUT/DELETE: There is no JBI message content
      • 
	
    
	
    • 
	
  • A JBI attachment is created according to the HTTP method of the incoming REST request:
	
      
		
    • GET/DELETE: There is no JBI attachment created
      • 
		
    • POST: A JBI attachment is created from the HTTP body if the Content-Type HTTP header contains a non XML content type.
      • 
		
    • PUT: A JBI attachment is created from the HTTP body
      • 
	
    
	
    • 
	
  • The HTTP headers are added to the the protocol header JBI message property
    • 
	
  • The MEP is defined by the petalsCDK:mep extension.
    • 





A WADL is available at the following URL: (TBC)

A WSDL 2.0 is available at the following URL: (TBC)



Configuration



Configuration of a Service Unit to consume a service (JBI)











 Parameter 
 Description 
 Default 
 Required 




 consumes 
 Refer JBI service to invoke into the JBI bus. 

You can define an explicit endpoint: interface (QName) / Service (QName) / Endpoint (String) attributes. 

Or define implicit endpoint, to let the container routing according to QOS configurations (HA...): 

-by Interface attribute (QName) 

-by Service attribute (QName) 		
 - 
 Yes 














Configuration of a Service Unit to consume a service (CDK)











 Parameter 
 Description 
 Default 
 Required 




 mep 
 Message exchange pattern abbreviation. This parameter can be used in conjunction with the method of the CDK Listeners: createMessageExchange(Extensions extensions). 

This method returns a CDK Exchange corresponding to the type of the specified pattern. 		
 - 
 Yes 




 operation 
 Operation to call on a service. This parameter can be used in conjunction with the sending methods of the Listeners. If no operation is specified in the Message Exchange to send, this parameter will be used. 
 - 
 No 




 timeout 
 Timeout in milliseconds of a synchronous send. This parameter can be used in conjunction with the sendSync(Exchange exchange) method of the Listeners. Set 0 for an infinite timeout. 
 30000 
 No 













Service Unit attributes to consume services











 Attribute 
 Description 
 Default value 
 Required 




 service-name 
 Web Service name to expose. 
 
 
No

 		











Service Unit descriptor



The service unit is configurable via its extensions in the jbi.xml file:









Service Unit content



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


    
	
  • The META-INF/jbi.xml descriptor file as described above
    • 





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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