Understanding and Handling ValidationException in AWS Proton

Introduction

AWS Proton is a fully managed deployment service that enables users to automate and streamline the process of deploying and managing container-based applications at scale. It provides a simple and consistent management experience, allowing developers to focus on writing code rather than worrying about the deployment process.

While working with AWS Proton, you may come across the ValidationException of com.amazonaws.services.proton.model. In this article, we’ll dive deep into this exception, understand its use cases, and learn how to handle it effectively. By the end, you’ll have a thorough understanding of ValidationException and be able to troubleshoot related issues.

Understanding ValidationException in AWS Proton

The ValidationException is an exception class provided by the proton.model package in the AWS SDK for Proton. It is thrown when one or more input parameters provided by the user fail to pass the validation checks set by AWS Proton. In simpler terms, it indicates that the request made to AWS Proton contains invalid or missing values.

The ValidationException can occur in various scenarios, such as:

1. Invalid template properties: When creating a service or environment template in AWS Proton, you need to provide various properties and their values. If any of these values are missing or incorrect, AWS Proton raises a ValidationException.

   // Example: Creating a service template
      
   CreateServiceTemplateRequest request = new CreateServiceTemplateRequest()
       .withName("MyServiceTemplate")
       .withDescription("A sample service template")
       .withTemplateName("my-service-template") // Invalid - contains invalid characters
       .withCompatibleEnvironmentTemplates(environmentTemplateArnList);
          
   protonClient.createServiceTemplate(request);
   

2. Missing required parameters: AWS Proton has certain mandatory parameters that must be provided while making API requests. Failure to include these required parameters leads to a ValidationException.

   // Example: Creating an environment template
      
   CreateEnvironmentTemplateRequest request = new CreateEnvironmentTemplateRequest()
       .withTemplateName("MyEnvironmentTemplate") // Missing required property - description
       .withProvisioning(Provisioning.DIY);
          
   protonClient.createEnvironmentTemplate(request);
   

3. Invalid input values: AWS Proton validates the input values according to its own predefined rules. If any of the input values violate these rules, a ValidationException is thrown.

   // Example: Updating a service instance
      
   UpdateServiceInstanceRequest request = new UpdateServiceInstanceRequest()
       .withServiceInstanceArn("arn:aws:proton:us-west-2:123456789012:service-instance/MY_SERVICE_INSTANCE_ARN") // Invalid ARN format
       .withSpec(specification)
       .withDeploymentType(DeploymentType.REPLACE_SERVER);
          
   protonClient.updateServiceInstance(request);
   

Handling ValidationException

When handling a ValidationException, it is essential to capture the specific error message and take appropriate actions. Here’s a step-by-step guide to effectively handle the exception:

1. Catch the exception: Surround the relevant code block with a try-catch block to catch the ValidationException thrown by AWS Proton.

   try {
       // Code that may cause a ValidationException
   } catch (ValidationException e) {
       // Handle the exception here
   }
   

2. Extract error details: The ValidationException provides various methods to help extract error details. The most common methods include getMessage(), getErrorCode(), and getValidationErrors(). Utilize these methods to access the error message, error code, and specific validation errors respectively.

   try {
       // Code that may cause a ValidationException
   } catch (ValidationException e) {
       String errorMessage = e.getMessage();
       String errorCode = e.getErrorCode();
       List<ValidationExceptionField> validationErrors = e.getValidationErrors();
       // Process the error details
   }
   

3. React to the error: Based on the error details, you can customize your application’s response. You may choose to log the error, prompt the user for correct inputs, or gracefully terminate the application when encountering critical errors.

   try {
       // Code that may cause a ValidationException
   } catch (ValidationException e) {
       String errorMessage = e.getMessage();
       String errorCode = e.getErrorCode();
       List<ValidationExceptionField> validationErrors = e.getValidationErrors();
          
       // Log the error
       logger.error(errorMessage);
          
       // Prompt the user for correct inputs
       userInputDialog.displayErrorMessage(errorMessage);
          
       // Gracefully terminate the application when critical errors occur
       if (errorCode.equals("CriticalError123")) {
           System.exit(1);
       }
   }
   

Conclusion

In this article, we explored the ValidationException of com.amazonaws.services.proton.model in AWS Proton. We learned that the exception is thrown when input parameters fail to pass validation checks, highlighting the need for correct and complete values in requests.

Additionally, we discussed various scenarios in which the ValidationException can occur, providing code examples for each case. By understanding the exception and following the best practices outlined for handling it, you can effectively troubleshoot and resolve issues related to the ValidationException.

Continue exploring the AWS Proton documentation and API references for further details and comprehensive usage examples.

Reference Links:

• AWS Proton Documentation
• AWS Proton API Reference

We hope this article has helped you grasp the concepts around ValidationException and equipped you with the knowledge to handle it effectively. Happy Proton development!