Validate all cloudformation files in a s3 folder

Question

CloudFormation validate supports validating a cloudformation template in s3.
How to validate all files in a s3 location. The files are located in a folder.

Answer 1

You can use the below python script to validate all cloudformation template in s3 bucket/folder
The below script generates Object Url/Public Url of all files in a s3 folder and then passes the url to validate_file function

import boto3

s3_uri="s3://BUCKET_NAME/FOLDER_1/FOLDER2/" # S3 URI of the folder you want to recursively scan, Replace this with your own S3 URI

# Split the s3 uri to extract bucket name and the file prefix
# Splitting S# 3 URI will generate an array
# Combine the appropirate elements of the array to extraxt BUCKET_NAME and PREFIX
arr=s3_uri.split('/')
bucket =arr[2]
prefix=""
for i in range(3,len(arr)-1):
    prefix=prefix+arr[i]+"/"
    
s3_client = boto3.client("s3")
    
def validate_file(object_url): # function to validate cloudformation template
    cloudformation_client = boto3.client('cloudformation')
    
    response = cloudformation_client.validate_template(
        TemplateURL=object_url
    )
    print(response) # print the response
    

def get_all_s3_files(bucket,prefix,s3_client): # generate object url of all files in the folder and pass it to validate function

    response = s3_client.list_objects_v2(Bucket=bucket,  Prefix=prefix) # Featch Meta-data of all the files in the folder
    files = response.get("Contents")
    for file in files: # Iterate through each files
        file_path=file['Key']
        object_url="https://"+bucket+".s3.amazonaws.com/"+file_path #create Object URL  Manually
        print("Object Url =  "+object_url)
        if object_url.endswith(".yml"):
            validate_file(object_url=object_url) # validate all files

get_all_s3_files(bucket=bucket,prefix=prefix,s3_client=s3_client)