Headers not being passed back to ALB

[shamimmirzai]

Firstly thanks for this awesome project. I have my lambda functions being called by the ALB and it looks like the headers that I set in my php code are not being sent back in the headers field of the json response back to the ALB. Therefore, I cannot set the content type for my responses so they always end up being octet-stream. This is my very simple php function:

<?php
  header('Content-Type: text/html');
  phpinfo();
?>

and when the response reaches my browser via the ALB, the content type is the default octet-stream. According to the AWS Lambda Functions as Targets the response that bootstrap needs to send back to the ALB must be json like this:

{
    "isBase64Encoded": false,
    "statusCode": 200,
    "statusDescription": "200 OK",
    "headers": {
        "Set-cookie": "cookies",
        "Content-Type": "application/json"
    },
    "body": "Hello from Lambda (optional)"
}

I could be mistaken, but I believe bootstrap is failing to set the headers field in that json response.

Any assistance would be appreciated. Thanks.

[daftspunk]

To solve this issue, enable Multi value headers in AWS:

1. Open AWS console
2. Navigate to EC2 > Load Balancing > Target Groups
3. Select relevant Target Group
4. Click Edit under Attributes
5. Set Multi value headers to Enabled

The proper headers should return now