Building a Simple Microservice

Build a simple microservice using Catalyst Basic I/O Functions and integrate it with Zoho CRM to send automated counter-based email alerts when more than a specific number of leads are created

Configure the Function

Let's begin coding the microservice.

The functions directory, in this case functions/countfunction, contains:

  • The CountAlert.java main function file
  • The catalyst-config.json configuration file
  • The JAR library files
  • Other dependencies

We will be adding code in the CountAlert.java file. We will not be modifying the code of the configuration file. You can use any IDE of your choice to configure the function.

Note: Please go through the code given in this section for understanding it better.

Copy the code given below and paste it in CountAlert.java and save the file.

  • View code for CountAlert.java

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    import com.catalyst.Context;
    import com.catalyst.basic.BasicIO;
    import com.catalyst.basic.ZCFunction;
    import com.zc.component.cache.ZCCache;
    import com.zc.component.mail.ZCMail;
    import com.zc.component.mail.ZCMailContent;
    
    import java.util.logging.Logger;
    import java.util.logging.Level;
    
    public class CountAlert implements ZCFunction {
     private static final Logger LOGGER = Logger.getLogger(CountAlert.class.getName());
    
     private static final String FROM_EMAIL="emma@zylker.com"; // The email address of the sender. Replace this with the email address you configured in Mail.
    
     private static final String TO_EMAIL="brandon.cooper@zylker.com"; // Replace this with the email address that you want the alert email to be sent to. 
    
     @Override
        public void runner(Context context, BasicIO basicIO) throws Exception {
    
      try {
       // Passes the feature name that was obtained from the input as the parameter. The feature name can be 'CRM' or 'Desk'.
       String featureName = (String) basicIO.getParameter("feature_name");
    
       // Passes the threshold count that was obtained from the input as the parameter
       String mailCountThreshold = (String) basicIO.getParameter("mail_count_threshold");
    
       // Gets the current count for the feature from the default segment of Catalyst Cache
       String value = ZCCache.getInstance()
              .getCacheValue("COUNTER_" + featureName)
              .getValue();
    
       // If the value is null, then the count is set to 1. This is done during the first execution for the feature.
       if (value == null) {
        ZCCache.getInstance()
            .putCacheValue("COUNTER_" + featureName, String.valueOf(1), 1l);
       } else {
        Integer count = Integer.valueOf(value);
    
        // If the value is not null, then the count is incremented by 1.
        count++;
    
        // Writes the count value to the default segment of Catalyst cache
        ZCCache.getInstance().putCacheValue("COUNTER_"+featureName,count.toString(),1l);
    
        // If the current count is greater than the threshold value, then an email alert is sent to the receiver configured above
        if (count > Integer.valueOf(mailCountThreshold)) {
         ZCMailContent content = ZCMailContent.getInstance();
         content.setFromEmail(FROM_EMAIL);
         content.setSubject("Alert!");
         content.setContent("Count exceeded the threshold limit for the feature:" +featureName);
         content.setToEmail(TO_EMAIL);
         ZCMail.getInstance()
            .sendMail(content);
         LOGGER.log(Level.INFO, "Email alert sent");//Written to the logs. You can view this log from Logs under the Monitor section in the console
        }
       }
    
       // Handles the 200 status code
       basicIO.setStatus(200);
       basicIO.write("The function executed successfully");
      }catch(Exception e)
      {
       LOGGER.log(Level.SEVERE,"Exception occurred while processing",e); //Written to the logs. You can view this log from Logs under the Monitor section in the console
    
       // Handles the 500 status code, when an exception occurs
       basicIO.setStatus(500);
       basicIO.write("Error in the function execution");
      }
     }
    }
    

Before you proceed to the next step, ensure that you replace the values of FROM_EMAIL and TO_EMAIL in the code as directed.

As discussed in the Introduction, the function obtains the inputs for feature_name and mail_count_threshold variables from the user through the API, when it is invoked. It obtains the current counter value from the cache and then increments it by 1 after every invocation. It then writes the new counter value to the cache.

Note: Since we are using the default segment in Catalyst Cache, we need not configure it. You can learn more about this from the Cache help page.

If the current counter value is greater than the threshold limit specified by the user, the email alert is sent to the address defined in the code. This information is also pushed to Catalyst Logs with an appropriate message. You can check this from Logs under the Monitor section in the Catalyst console.

The functions directory is now configured.