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Understanding InvalidMaxResultsException in AWS CodeCommit for Effective Application Development

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By Exception Decoded 4 min read

When working with AWS CodeCommit, developers often encounter various exceptions that can impact the efficacy of their applications. One such exception is the InvalidMaxResultsException. This article dives deep into understanding this exception, its causes, and how to handle it effectively in your applications. We will also provide useful code examples to illustrate the correct usage of the CodeCommit client.

What is AWS CodeCommit?

AWS CodeCommit is a fully managed source control service that makes it easy for teams to host secure and scalable Git repositories. It allows developers to store and manage source code, enabling seamless collaboration on projects.

What is InvalidMaxResultsException?

InvalidMaxResultsException is thrown when the maxResults parameter in the AWS CodeCommit API is set to an invalid value. This could be due to specifying a negative number, a number that exceeds the maximum allowed limit, or a type mismatch.

Understanding when to expect this exception can save developers from unwarranted debugging and enhance application stability.

Common Causes of InvalidMaxResultsException

  1. Negative Value: The maxResults parameter should always be a positive integer. Specifying a negative value will trigger this exception.
  2. Exceeding Maximum Limits: CodeCommit has a limit for maxResults. Generally, it should not exceed 100. Values exceeding this can cause InvalidMaxResultsException.
  3. Type Mismatch: If the maxResults parameter is not provided as an integer, it may lead to this exception being thrown.

Handling InvalidMaxResultsException

Proper exception handling is essential for a smooth user experience and robust application functioning. Below are strategies and code examples for handling InvalidMaxResultsException in AWS CodeCommit effectively.

Example Code: Catching InvalidMaxResultsException

Here’s a simple example demonstrating how to handle InvalidMaxResultsException in a Java application using the AWS SDK.

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import com.amazonaws.services.codecommit.AWSCodeCommit;
import com.amazonaws.services.codecommit.AWSCodeCommitClientBuilder;
import com.amazonaws.services.codecommit.model.ListBranchesRequest;
import com.amazonaws.services.codecommit.model.ListBranchesResult;
import com.amazonaws.services.codecommit.model.InvalidMaxResultsException;

public class CodeCommitExample {
    public static void main(String[] args) {
        AWSCodeCommit codeCommit = AWSCodeCommitClientBuilder.defaultClient();

        try {
            ListBranchesRequest request = new ListBranchesRequest()
                    .withRepositoryName("MyRepo")
                    .withMaxResults(150); // Invalid max results, should be <= 100
            
            ListBranchesResult response = codeCommit.listBranches(request);
            System.out.println("Branches: " + response.getBranches());
        } catch (InvalidMaxResultsException e) {
            System.err.println("Error: " + e.getMessage());
            // Handle the exception (for example, by setting maxResults to a permitted value)
            int validMaxResults = 100; // Example of a valid maxResults value.
            // Retry the request with validMaxResults
        }
    }
}

In this example:

  1. The ListBranchesRequest is initialized with an invalid maxResults value of 150.
  2. If InvalidMaxResultsException occurs, we catch it and print an error message.
  3. The code suggests action by resetting the maxResults to a valid number.

Recommendations for Using maxResults Safely

To avoid hitting the InvalidMaxResultsException, developers should follow these recommendations:

  • Always Validate Input: Check the value of maxResults before making the API call.
  • Use Constants for Limits: Define a constant for maximum allowed maxResults and use this throughout your application.
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public static final int MAX_RESULTS_LIMIT = 100;

public ListBranchesResult safeListBranches(AWSCodeCommit codeCommit, String repoName, int maxResults) {
    if (maxResults < 0 || maxResults > MAX_RESULTS_LIMIT) {
        maxResults = MAX_RESULTS_LIMIT; // Set to the limit as a fallback
    }

    ListBranchesRequest request = new ListBranchesRequest()
            .withRepositoryName(repoName)
            .withMaxResults(maxResults);

    return codeCommit.listBranches(request);
}

Validating API Parameters

Validating API parameters can prevent exceptions from occurring. Developers should set constraints and checks for parameters to ensure they are within acceptable limits. This is key in production applications to maintain performance and avoid crashes.

Testing Your Configurations

Always write unit tests for your functions that interact with AWS services. By simulating different scenarios (including invalid values), you enhance the robustness of your application.

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import org.junit.Test;
import static org.junit.Assert.*;

public class CodeCommitTest {
  
    @Test
    public void testSafeListBranchesValidInput() {
        AWSCodeCommit mockCodeCommit = // create a mock or stub
        int validMaxResults = 50;
        
        ListBranchesResult result = safeListBranches(mockCodeCommit, "MyRepo", validMaxResults);
        
        assertNotNull(result);
        assertTrue(result.getBranches().size() <= validMaxResults);
    }

    @Test
    public void testSafeListBranchesInvalidInput() {
        AWSCodeCommit mockCodeCommit = // create a mock or stub
        int invalidMaxResults = 150; 

        ListBranchesResult result = safeListBranches(mockCodeCommit, "MyRepo", invalidMaxResults);

        assertNotNull(result);
        assertTrue(result.getBranches().size() <= MAX_RESULTS_LIMIT);
    }
}

Conclusion

The InvalidMaxResultsException in AWS CodeCommit is a common hurdle developers face when they misconfigure the maxResults parameter. By understanding the reasons behind this exception and employing proper error handling and validation strategies, developers can create robust applications that communicate smoothly with CodeCommit.

Following best practices for configuring API parameters ensures that your applications are more resilient, leading to an enhanced development experience and improved performance in production.

References

AWS, AWS CodeCommit
aws codecommit com.amazonaws.services.codecommit.model
This post is licensed under CC BY 4.0 by the author.