Thursday, October 29, 2015

Integrate WSO2 registry lifecycle with WSO2 API Manager 1.10



An API artifact has its own lifecycle to govern.A life-cycle contains set of states,actions happened during each state transitions and check list items before do a state transition.With previous APIM previous releases,we had a pre-defined lifecycle with pre-defined six states as ‘CREATED’,’PROTOTYPED’,’PUBLISHED’,’BLOCKED’,’DEPRECATED’,’RETIRED’ and pre-defined actions engaged with each state transitions  which cannot be extend or customize.There was a requirement came from many users,can’t they extend the default API lifecycle engaged with WSO2 API Manager as to add their defined state names,invoke their custom actions during state transitions [eg:send notifications at each transition],add custom checklist items before state transitions.


To achieve above,we decided to integrate WSO2 registry based lifecycle with APIManager.WSO2 registry based lifecycle provides a configurable way to define the lifecycle of an artifact which a user can easily extend.For more information ,refer http://wso2.com/library/tutorials/lifecycles-aspects-wso2-governance-registry/
From APIM 1.10 onwards the default API lifecycle has defined as a xml configuration which a user laterly can extend easily.Following is the default API lifecycle xml configuration shipped with AM 1.10 product and same can be download from here.You can find this from management console by navigating to Extenstions->Configure->Lifecycles left menu.


    
    
        
            

                
                    
                        
                            
                            
                            
                            
                        

                        
                            
                            
                            
                            
                        
                    
                    
                    

                
                
                    
                        
                            
                            
                            
                            
                        
                    
                    
                    
                


                

                    

                        
                            
                            
                            
                            
                            
                            
                            
                            

                        
                    
                    
                    
                    
                    
                    
                

                
                    
                        
                            
                            
                            
                            
                        
                    
                    
                    
                

                
                    
                        
                            
                            
                        
                    
                    
                

                
                
            
        
    

In above configuration,following are the important points.


  1. Lifecycle Name- APILifecycle
  2. Set of states -which are defined as   config elements.In default API lifecycle,it has six states as CREATED,PROTOTYPED,PUBLISHED,BLOCKED,DEPRECATED,RETIRED
  3. A list of checklist items to be satisfied-  
         When the API state is in ‘CREATED’ state and have multiple versions,we are checking two checklist items as ‘Deprecate Old Versions’ and ‘Require Re-subscriptions’.These check list items are defined as    configuration element.
    4.   State transition events -These events are to define from which state to which target state an API can be moved.These are defined as config elements in registry lifecycle. Below state transition chart explain clearly the state transition events in default API lifecycle.


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    5.   Actions for each state transitions
         This is the important part.For each state transition,there has to be an action triggered which will execute during state transition.For example,when an API state change from ‘CREATED’ to ‘PUBLISHED’,from APIM side,there will be an execution happend as a relative synapse API xml element will be created and related API data will be saved in database.To happen that execution,developer has to define the execution for state transtion in above registry lifecycle configuration configuration.


With the above change,lifecycle tab in API Publisher UI has also changed.






On AM 1.10 APIPublisher,the lifecycle UI is showing the current state of an API and target events defined in API lifecycle for that state as buttons.Note this UI is dynamically generated based on defined API LifeCycle xml configuration [Previously this page is static].Thus if you customized the default API LifeCycle configuration included states,transition events or check list items,those changes will be rectified in the lifecycle tab of APIPublisher UI accordingly.


Extension points for the API Lifecycle

With the registry life-cycle integration,now a developer can changed the API lifecycle easily with modify the above mentioned APILifecycle xml configuration.Note he has to keep the lifecycle name as ‘APILifeCycle’ to engage it for an API by default.
He can define his own state names except ‘Published’ and ‘Prototyped’ states as those two two will be use from APIPublisher API creation wizard.He can change state transition events as per their environmental preference by changing APILifecycle accordingly.He can add custom checklist items for specific state transitions.


And also a developer can change the execution code for each state transitions.In default API lifecycle,we have used same execution class  called ‘org.wso2.carbon.apimgt.impl.executors.APIExecutor’
[https://github.com/wso2/carbon-apimgt/blob/release-1.10.x/components/apimgt/org.wso2.carbon.apimgt.impl/src/main/java/org/wso2/carbon/apimgt/impl/executors/APIExecutor.java] for all the state transitions.But a developer can plug their own execution code with modifying the lifecycle configuration.For example,if he want to add notifications for a specific state  transition,then he can plug his own custom execution class for that particular state in APILifeCycle.


Once a developer changed states,events or checklist items,those will be rectified in APIPublisher life-cycle tab.
APIM 1.10 will be release by end quarter of 2015 and you'll able to try out these changes by the that release out.









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