AWS Lambda (sdk) InvalidZipFileException encountered when deploying a Lambda function.

Understanding AWS Lambda

AWS Lambda is a serverless compute service that lets you run code without provisioning or managing servers. It executes your code only when needed and scales automatically, from a few requests per day to thousands per second. Lambda is designed to handle various workloads, including data processing, real-time file processing, and backend services.

Identifying the Symptom

When deploying a Lambda function, you might encounter the InvalidZipFileException. This error indicates that the uploaded ZIP file containing your Lambda function code is either invalid or corrupted.

Observed Error

The error message typically reads: InvalidZipFileException: The uploaded ZIP file is invalid or corrupted. This message appears during the deployment process, either via the AWS Management Console, AWS CLI, or SDKs.

Exploring the Issue

The InvalidZipFileException occurs when the Lambda service cannot read or extract the contents of the uploaded ZIP file. This can happen due to several reasons, such as incorrect file structure, unsupported file format, or corruption during the upload process.

Common Causes

• The ZIP file is not properly structured, missing necessary files or folders.
• The ZIP file is corrupted during the upload process.
• Unsupported file format or compression method used.

Steps to Fix the Issue

To resolve the InvalidZipFileException, follow these steps:

1. Verify the ZIP File Structure

Ensure that your ZIP file contains all necessary files and folders. The root of the ZIP file should contain your Lambda function code and any dependencies. Avoid nesting the files within additional directories.

2. Recreate the ZIP File

Use a reliable tool to recreate the ZIP file. For example, you can use the zip command on Unix-based systems:

zip -r function.zip .

This command zips all files in the current directory into function.zip.

3. Check for Corruption

Ensure the ZIP file is not corrupted. You can test the integrity of the ZIP file using tools like unzip:

unzip -t function.zip

This command tests the ZIP file for errors.

4. Re-upload the ZIP File

Once you have verified and recreated the ZIP file, re-upload it to AWS Lambda. You can do this via the AWS Management Console or using the AWS CLI:

aws lambda update-function-code --function-name YourFunctionName --zip-file fileb://function.zip

Additional Resources

For more information on packaging and deploying Lambda functions, refer to the following resources:

• AWS Lambda Packaging Guide
• AWS Lambda Product Page
• AWS CLI Command Reference