APIM Gateway tracks the analytics data if analytics is enabled and configured. But in order to use this feature APIM analytics need to be configured. If analytics is correctly configured these data processed and generate summary data that can be visualized in publisher and store statistics apps. But there can be requirements to get these analytics data without configuring apim analytics. Because adding another analytics server or deployment to the existing setup may need additional changes and required additional resources. As a solution, you can get these data to a file similar to the logging.

For this, we can add a custom event publisher using existing extension points and publish these data to the logger instead of the analyzer. So we can use the APIM component to a maven project and apply the configuration in the gateway node.

• Create a maven project
• Include required repository and maven dependency

  <?xml version="1.0" encoding="UTF-8"?>
  <project xmlns="http://maven.apache.org/POM/4.0.0"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
      <modelVersion>4.0.0</modelVersion>
  
      <groupId>com.rukspot.samples</groupId>
      <artifactId>com.rukspot.samples.log_analytics</artifactId>
      <version>1.0-SNAPSHOT</version>
  
      <dependencies>
          <dependency>
              <groupId>org.wso2.carbon.apimgt</groupId>
              <artifactId>org.wso2.carbon.apimgt.usage.publisher</artifactId>
              <version>6.4.50</version>
          </dependency>
      </dependencies>
  
      <repositories>
          <repository>
              <id>wso2-nexus</id>
              <name>WSO2 internal Repository</name>
              <url>http://maven.wso2.org/nexus/content/groups/wso2-public/</url>
              <releases>
                  <enabled>true</enabled>
                  <updatePolicy>daily</updatePolicy>
                  <checksumPolicy>ignore</checksumPolicy>
              </releases>
          </repository>
      </repositories>
  </project>
  				

• Create a class which is extended to org.wso2.carbon.apimgt.usage.publisher.APIMgtUsageDataBridgeDataPublisher
• Override all the method and implement nothing to ignore its functions
• Log all the required data by converting it to a JSON

  package com.rukspot.samples.analytics.publisher;
  
  import com.google.gson.Gson;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.wso2.carbon.apimgt.api.APIManagementException;
  import org.wso2.carbon.apimgt.usage.publisher.APIMgtUsageDataBridgeDataPublisher;
  import org.wso2.carbon.apimgt.usage.publisher.dto.AlertTypeDTO;
  import org.wso2.carbon.apimgt.usage.publisher.dto.FaultPublisherDTO;
  import org.wso2.carbon.apimgt.usage.publisher.dto.RequestResponseStreamDTO;
  import org.wso2.carbon.apimgt.usage.publisher.dto.ThrottlePublisherDTO;
  
  public class FilePublisher extends APIMgtUsageDataBridgeDataPublisher {
      private static final Log log = LogFactory.getLog(FilePublisher.class);
      private Gson gson = new Gson();
  
      public FilePublisher() {
          // Do nothing
      }
  
      @Override
      public void init() {
          // Do nothing
      }
  
      @Override
      public void publishEvent(FaultPublisherDTO faultPublisherDTO) {
          log.info(gson.toJson(faultPublisherDTO));
      }
  
      @Override
      public void publishEvent(ThrottlePublisherDTO throttPublisherDTO) {
          log.info(gson.toJson(throttPublisherDTO));
      }
  
      @Override
      public void publishEvent(AlertTypeDTO alertTypeDTO) throws APIManagementException {
          // Required only to log alert configurations
          // log.info(gson.toJson(alertTypeDTO));
      }
  
      @Override
      public void publishEvent(RequestResponseStreamDTO requestStream) {
          log.info(gson.toJson(requestStream));
      }
  }
  
  				

• Download and extract WSO2 API Manager 2.6.0
• Enable analytics in wso2 Gateway
• Disable workflow publishing in order to disable connectivity check to the Analytics
• Define the custom publisher in <AM_HOME>/repository/conf/api-manager.xml

  <Analytics>
      <!-- Enable Analytics for API Manager -->
      <Enabled>false</Enabled>
  
      <!--Skip workflow data publisher initiation and even publishing-->
      <SkipWorkflowEventPublisher>true</SkipWorkflowEventPublisher>
  
      <!-- API Usage Data Publisher. -->
      <PublisherClass>org.wso2.carbon.apimgt.usage.publisher.APIMgtUsageDataBridgeDataPublisher</PublisherClass>
  
      ......
  </Analytics>
  				

• Define the package level to be log in <AM_HOME>/repository/conf/log4j.properties

  log4j.category.com.rukspot.samples.analytics.publisher=INFO
  				

• Build the source code with 'mvn clean install'
• Copy the build jar or from github to the <AM_HOME>/repository/components/lib

• Restart the server once above configurations are applied
• Deploy an API and get a token once subscribe
• Invoke the API and observe the log in <AM_HOME>/repository/wso2carbon.log

  [2019-04-06 19:04:20,658]  INFO - FilePublisher {"applicationConsumerKey":"waxwrjrA2vWIqnxDOJ0PST7IXLwa","applicationName":"DefaultApplication","applicationId":"1","applicationOwner":"admin","apiContext":"/pizzashack/1.0.0","apiName":"PizzaShackAPI","apiVersion":"1.0.0","apiResourcePath":"/menu","apiResourceTemplate":"/menu","apiMethod":"GET","apiCreator":"admin","apiCreatorTenantDomain":"carbon.super","apiTier":"Unlimited","apiHostname":"172.17.0.1","username":"admin@carbon.super","userTenantDomain":"carbon.super","userIp":"10.10.10.2","userAgent":"curl/7.47.0","serviceTime":3,"requestTimestamp":1554557657696,"throttledOut":false,"backendTime":20,"responseCacheHit":false,"responseSize":0,"protocol":"https-8243","responseCode":200,"destination":"https://localhost:9443/am/sample/pizzashack/v1/api/","metaClientType":"PRODUCTION","responseTime":23,"gatewayType":"SYNAPSE","correlationID":"5fe11502-8d98-439d-9056-8b5762236f4a","label":"Synapse","executionTime":{"securityLatency":0,"throttlingLatency":0,"requestMediationLatency":2,"responseMediationLatency":0,"backEndLatency":20,"otherLatency":0}}
  
  [2019-04-06 19:07:43,363]  INFO - FilePublisher {"applicationConsumerKey":"waxwrjrA2vWIqnxDOJ0PST7IXLwa","applicationName":"DefaultApplication","applicationId":"1","applicationOwner":"admin","apiContext":"/pizzashack/1.0.0","apiName":"PizzaShackAPI","apiVersion":"1.0.0","apiResourcePath":"/menu","apiResourceTemplate":"/menu","apiMethod":"GET","apiCreator":"admin","apiCreatorTenantDomain":"carbon.super","apiTier":"Unlimited","apiHostname":"172.17.0.1","username":"admin@carbon.super","userTenantDomain":"carbon.super","userIp":"10.10.10.2","userAgent":"curl/7.47.0","serviceTime":4,"requestTimestamp":1554557863334,"throttledOut":false,"backendTime":17,"responseCacheHit":false,"responseSize":0,"protocol":"https-8243","responseCode":200,"destination":"https://localhost:9443/am/sample/pizzashack/v1/api/","metaClientType":"PRODUCTION","responseTime":21,"gatewayType":"SYNAPSE","correlationID":"cb93d815-d738-4879-8305-2124fb48ff39","label":"Synapse","executionTime":{"securityLatency":3,"throttlingLatency":0,"requestMediationLatency":0,"responseMediationLatency":0,"backEndLatency":17,"otherLatency":0}}
  
  				

• Maven project is available on github