AWS Lambda HTTP 500 scenarios When Invoking from API Gateway with Python 3.8
I've spent hours debugging this and I'm building a feature where I'm deploying to production and Could someone explain I've searched everywhere and can't find a clear answer... I'm trying to set up an AWS Lambda function that processes user uploads and is triggered via an API Gateway. The function is written in Python 3.8 and is supposed to return a success response after processing the file. However, I keep receiving an HTTP 500 Internal Server behavior when invoking the Lambda function through API Gateway. The function runs successfully when tested directly in the AWS Lambda console, but fails when triggered from API Gateway. Here's a snippet of my Lambda function: ```python import json def lambda_handler(event, context): try: # Simulate file processing body = json.loads(event['body']) # Assume body contains a key 'file_data' file_data = body['file_data'] # Process the file_data (dummy processing) processed_data = file_data.upper() return { 'statusCode': 200, 'body': json.dumps({'message': 'File processed successfully!', 'data': processed_data}) } except Exception as e: print(f'behavior: {str(e)}') return { 'statusCode': 500, 'body': json.dumps({'behavior': str(e)}) } ``` In my API Gateway configuration, I've set the integration type to Lambda Function and ensured that the Lambda function has the correct permissions. I also enabled CORS on the API Gateway. The test payload I'm using looks like this: ```json { "file_data": "example content" } ``` When I monitor the logs in CloudWatch, I see the following behavior message: `Unhandled exception in lambda_handler: KeyError: 'body'`. I suspect this might be related to how the API Gateway formats the input to the Lambda function, but I haven't been able to pinpoint the exact scenario. I've tried adjusting the mapping template in the API Gateway to ensure the `body` is correctly passed, but the behavior continues. Any insights on what could be causing this scenario? My development environment is Ubuntu. Any ideas what could be causing this? How would you solve this? I'm coming from a different tech stack and learning Python. Could someone point me to the right documentation? Hoping someone can shed some light on this. Has anyone else encountered this? I'm working with Python in a Docker container on Windows 10. Thanks in advance! Any feedback is welcome!