lambda_dependencies.py

# Lambda that builds dependencies out of the requirements.txt using it's native OS (AL2) and uploads to S3
# Useful for building binary dependencies for Lambdas

import subprocess, shutil, os, zipfile, boto3

BUCKET_NAME = 'BUCKET_NAME'
S3_KEY = 'lambda/build/function.zip'
PYTHON_VERSION = 'python'

build_dir = '/tmp/deps'
zip_path = 'function.zip'
requirements_file = 'requirements.txt'
source_file = 'index.py'

def lambda_handler(event, context):
    if os.path.exists(build_dir):
        shutil.rmtree(build_dir)

    os.makedirs(build_dir)

    subprocess.check_call([PYTHON_VERSION, '-m', 'pip', 'install', '-r', requirements_file, '-t', build_dir])
    shutil.copy(source_file, build_dir)

    with zipfile.ZipFile(zip_path, 'w', zipfile.ZIP_DEFLATED) as zipf:
        for root, dirs, files in os.walk(build_dir):
            for file in files:
                abs_path = os.path.join(root, file)
                rel_path = os.path.relpath(abs_path, build_dir)
                zipf.write(abs_path, rel_path)

    s3 = boto3.client('s3')
    s3.upload_file(zip_path, BUCKET_NAME, S3_KEY)

    print(f"Uploaded to s3://{BUCKET_NAME}/{S3_KEY}")