AWS lambda using RAM by sending HTTP API request without external dependencies

index.py

import os
import boto3
import json
import botocore.auth
import botocore.credentials
from botocore.awsrequest import AWSRequest
from botocore.endpoint import BotocoreHTTPSession
from botocore.auth import SigV4Auth

    
def lambda_handler(event, context):
  account_id = context.invoked_function_arn.split(':')[4]
  host = 'ram.{}.amazonaws.com'.format(os.environ['AWS_REGION'])
  params = {
    'name': 'sharename', 
    'resourceArns': ['arn:aws:ec2:{}:{}:transit-gateway/{}'.format(os.environ['AWS_REGION'], account_id, 'tgw-01234567890')], 
    'principals': ['123456789012']
  }
  headers = {'Host': host}
  
  request = AWSRequest(method="POST", url="https://{}/createresourceshare".format(host), data=json.dumps(params), headers=headers)
  SigV4Auth(boto3.Session().get_credentials(), "ram", os.environ['AWS_REGION']).add_auth(request)    
 
  session = BotocoreHTTPSession()
  r = session.send(request.prepare())
  
  if r.status_code >= 200 and r.status_code <= 299:
    return json.loads(r._content)
  else:
    raise Exception(r.status_code, r._content)