Trigger a stack update optionaly passing new parameters (no wait)

trigger_update_stack.py

#!/usr/bin/env python
import argparse
import boto3

def main():
  parser = argparse.ArgumentParser(description='Update AWS CloudFormation stack while overriding a specific parameter.')
  parser.add_argument('--region', '-r', required=True, help='AWS region where the stack is located')
  parser.add_argument('--stack-name', '-s', required=True, help='Name of the CloudFormation stack')
  parser.add_argument('--parameters', '-p', default="", help='Example: key1=val1 key2=val2')
  args = parser.parse_args()

  cf = boto3.client('cloudformation', region_name=args.region)
  response = cf.describe_stacks(StackName=args.stack_name)
  parameters = response['Stacks'][0]['Parameters']

  updated_parameters = []
  new_parameters = {pair.split('=')[0]: pair.split('=')[1] for pair in args.parameters.split()}
  
  for param in parameters:
    key = param['ParameterKey']
    if key in new_parameters:
      updated_parameters.append({
        'ParameterKey': param['ParameterKey'],
        'ParameterValue': new_parameters[key],
        'UsePreviousValue': False
      })
    else:
      updated_parameters.append({
        'ParameterKey': key,
        'UsePreviousValue': True
      })

  update_response = cf.update_stack(
    UsePreviousTemplate=True,
    StackName=args.stack_name,
    Parameters=updated_parameters,
    Capabilities=['CAPABILITY_IAM', 'CAPABILITY_NAMED_IAM']
  )

  print(f"Update initiated, Stack ID: {update_response['StackId']}")
  return update_response['StackId']


if __name__ == '__main__':
  main()