Find all the lambda resources in a given cloudformation stack (AWS)

discover_lambdas.py

import argparse
import os
import boto3

boto3.setup_default_session(profile_name=os.environ.get("AWS_PROFILE", "default"))


def discover_lambdas(stack_name):
    cf = boto3.client("cloudformation")    
    paginator = cf.get_paginator("list_stack_resources")

    lambdas = []
    token = None

    result = paginator.paginate(PaginationConfig={"NextToken": token}, StackName=stack_name)

    for page in result:
        for resource in page["StackResourceSummaries"]:
            if resource["ResourceType"] == "AWS::Lambda::Function":
                lambdas.append(resource["PhysicalResourceId"])

    return lambdas


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Find all lambdas in a stack")
    parser.add_argument("--stack", help="The stack to search for lambdas", required=True)
    args = parser.parse_args()

    lambdas = discover_lambdas(args.stack)

    for l in lambdas:
        print(f"λ {l}")