AWS lambda policy to invoke another lambda

Question

I need to invoke the lambda function2 from lambda function1 using aws sdk.

So far I have the following policy on function1

        {
            "Sid": "AllowToInvokeLambda",
            "Effect": "Allow",
            "Action": "lambda:InvokeFunction",
            "Resource": "arn:aws:lambda:eu-west-1:XXX:function:function2"
        },

But it fails with AccessDeniedException: status code: 403

Answer 1

I think you need to double-check again your Lambda Permissions with Execution Role as below.

Ensure that it has the permission to invoke other Lambda functions. Here is a simple policy I use:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "VisualEditor0",
            "Effect": "Allow",
            "Action": "lambda:InvokeFunction",
            "Resource": "*"
        }
    ]
}

To test this, I have a simple code here:

    client = boto3.client('lambda')

    response = client.invoke(
        FunctionName='invoke-test-2',
        InvocationType='Event',
        Payload='{}',
    )
    
    print(response)

Here is the result: