lambda-recreate.py

#!/usr/bin/env python

import boto3
import logging
import os
import shutil
import zipfile

from botocore.errorfactory import ClientError

logger = logging.getLogger('')
sysHandler = logging.StreamHandler()
sysHandler.setFormatter(logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s'))
logger.addHandler(sysHandler)
logger.setLevel(logging.INFO)
logger = logging.getLogger(__file__)

WORKING_DIR = os.path.join(os.getcwd(), 'build')
ARCHIVE_PATH = os.path.join(WORKING_DIR, 'boto3-example.zip')
BUILD_DIR = os.path.join(WORKING_DIR, 'boto3-example')

S3_KEY = 'lambda_codes.zip'
S3_BUCKET = 'lambda-function-sandbox'

FUNCTION_NAME = 'lambda-boto3-example'
FUNCTION_RUNTIME = 'python3.8'
FUNCTION_ROLE_ARN = 'arn:aws:iam::***:role/role-name'

def generate_zip():
    logger.info(f'Generating Archive[{ARCHIVE_PATH}]')
    compression_method = zipfile.ZIP_STORED
    if os.path.exists(BUILD_DIR):
        shutil.rmtree(BUILD_DIR)

    os.makedirs(BUILD_DIR)
    lambda_handler_path = os.path.join(BUILD_DIR, 'lambda_handler.py')
    with open(lambda_handler_path, 'w') as stream:
        stream.write('''#!/usr/bin/env python

def handler(event=None, context=None):
    print("Hello Lambda")
''')
    with zipfile.ZipFile(ARCHIVE_PATH, 'w', compression_method) as archive:
        for root, dirs, files in os.walk(BUILD_DIR):
            for filename in files:
                if filename.endswith('.pyc'):
                    continue

                if filename == '__pycache__':
                    continue

                logger.info(f'Adding file[{filename}] to Archive')
                abs_filename = os.path.join(root, filename)
                if filename.endswith('.py'):
                    os.chmod(abs_filename, 0o755)

                relative_filepath = os.path.join(root.replace(BUILD_DIR, '').lstrip(os.sep), filename)
                zip_info = zipfile.ZipInfo(relative_filepath)
                zip_info.create_system = 3
                zip_info.external_attr = 0o755 << int(16)
                with open(abs_filename, 'rb') as file_stream:
                    archive.writestr(zip_info, file_stream.read(), compression_method)

            for dirname in dirs:
                continue

def upload_s3_object():
    s3_client = boto3.client('s3')
    logger.info(f'Uploading S3Archive[{ARCHIVE_PATH}] to S3[{S3_KEY}]')
    s3_client.upload_file(ARCHIVE_PATH, S3_BUCKET, S3_KEY)

def rebuild_lambda():
    lambda_client = boto3.client('lambda')
    try:
        lambda_client.get_function(FunctionName=FUNCTION_NAME)
    except (ClientError, lambda_client.exceptions.ResourceNotFoundException) as err:
        logger.info(f'Creating Lambda Function[{FUNCTION_NAME}]')
        details = lambda_client.create_function(
                FunctionName=FUNCTION_NAME,
                Runtime=FUNCTION_RUNTIME,
                MemorySize=256,
                Role=FUNCTION_ROLE_ARN,
                Handler='lambda_handler.handler',
                Code = {
                    'S3Bucket': S3_BUCKET,
                    'S3Key': S3_KEY,
                },
                Timeout=900, # 15 minutes
                Environment={
                    'Variables': {} # ENVVars
                },
                Layers=[])

    else:
        logger.info(f'Deleting Lambda Function[{FUNCTION_NAME}]')
        lambda_client.delete_function(FunctionName=FUNCTION_NAME)
        rebuild_lambda()
        

generate_zip()
upload_s3_object()
rebuild_lambda()