By default, subscription workflow applies to all the APIs. But in case if you need to apply workflow only for the selected APIs, there is no way to achieve that. But this can be achieved via the available workflow extensions.

The solution we are going to implement is, apply the workflow by checking the properties of an API. An example use case is as below. In case if you have two types of APIs name secured and public. But you need to review and approve subscription creation for secured APIs. Subscription creation for the public APIs is approved without user approval. Let’s see how we can implement this in APIM 3.0.0. Type of the API is defined as an API property and it is done by the API developer.

The default subscription workflow implementation for workflow engines is “org.wso2.carbon.apimgt.impl.workflow.SubscriptionCreationWSWorkflowExecutor”. We can extend the implementation and apply the new logic by overriding its implementation. In the workflow extension, we can check the API properties and check API contain a property “type” with a “secured” value. In such cases, we engage the user approval workflow. If the above property is not there, subscription creation completes without user interaction.

• WSO2 API Manager 3.0.0
• WSO2 Enterprise Integrator 6.5.0
• Configure API Manager for subscription workflow according to the official document

• Create a new maven project and include the following dependency

                      <dependency>
                          <groupId>org.wso2.carbon.apimgt</groupId>
                          <artifactId>org.wso2.carbon.apimgt.impl</artifactId>
                          <version>6.5.349</version>
                      </dependency>
                  

• Add a new java class that extends the “SubscriptionCreationWSWorkflowExecutor”
• Override the method “execute” with the following content.

                      SubscriptionWorkflowDTO subsWorkflowDTO = (SubscriptionWorkflowDTO) workflowDTO;
                      APIIdentifier apiIdentifier = new APIIdentifier(subsWorkflowDTO.getApiProvider(), subsWorkflowDTO.getApiName(),
                              subsWorkflowDTO.getApiVersion());
                      try {
                          APIConsumer apiConsumer = APIManagerFactory.getInstance().getAPIConsumer();
                          API api = apiConsumer.getAPI(apiIdentifier);
                          if (api.getAdditionalProperties().containsKey(WF_TYPE) && WF_TYPE_SECURED
                                  .equalsIgnoreCase(api.getAdditionalProperties().get(WF_TYPE).toString())) {
                              return super.execute(workflowDTO);
                          }
                      } catch (APIManagementException e) {
                          log.error("Error occurred while processing workflow request.", e);
                          throw new WorkflowException("Error occurred while processing workflow request.", e);
                      }
  
                      //Default flow: complete the subscription creation
                      workflowDTO.setStatus(WorkflowStatus.APPROVED);
                      WorkflowResponse workflowResponse = complete(workflowDTO);
                      super.publishEvents(workflowDTO);
  
                      return workflowResponse;
                  

• In this code sample, it will get the API ID and API object from the workflow details DTO it gets. Once the API properties are read, check “apiType” property is defined. If the property is defined and its value is “secured” execute the user approval workflow. Otherwise, it completes the workflow by approving the subscription.
• Build the project and copy target/com.rukspot.sample.apimgt.workflow.apibase-1.0-SNAPSHOT.jar to <APIM_HOME>/repository/components/lib/ directory
• Edit the /_system/governance/apimgt/applicationdata/workflow-extensions.xml registry resource and define the “SubscriptionCreation” workflow extension as follow.

                      <SubscriptionCreation executor="com.rukspot.sample.apimgt.workflow.apibase.SubscriptionWorkflow">
                           <Property name="serviceEndpoint">http://localhost:9765/services/SubscriptionApprovalWorkFlowProcess/</Property>
                           <Property name="username">admin</Property>
                           <Property name="password">admin</Property>
                           <Property name="callbackURL">https://localhost:8243/services/WorkflowCallbackService</Property>
                      </SubscriptionCreation>
                  

• Restart the APIM server

• Create an API with “apiType” property which is value is “secured”

• Create another API without the above property

• Create an application to subscribe to the above API

• Subscribe to the above APIs.

• You will see, “securedAPI” subscription is not yet activated.
• The admin portal will list approval tasks for the above APIs.

• Once the subscription is approved, it’s subscription status changed to “UNBLOCKED” in the dev portal.

Please find the sample code from GitHub