main.py

#!/usr/bin/env python3

# Copyright 2018 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# -*- coding: utf-8 -*-

import subprocess
import urllib.request
import os
from shutil import copytree, ignore_patterns, rmtree

# Version of Terraform that we're using
TERRAFORM_VERSION = '1.4.4'

# Download URL for Terraform
PLATFORM = 'linux'
TERRAFORM_DOWNLOAD_URL = (
    'https://releases.hashicorp.com/terraform/%s/terraform_%s_%s_amd64.zip'
    % (TERRAFORM_VERSION, TERRAFORM_VERSION, PLATFORM))

# Paths where Terraform should be installed
TERRAFORM_DIR = os.path.join('/tmp', 'terraform_%s' % TERRAFORM_VERSION)
TERRAFORM_PATH = os.path.join(TERRAFORM_DIR, 'terraform')

PROJECT_DIR = os.path.join('/tmp', 'project')


def check_call(args, cwd=None, printOut=False):
    """Wrapper for subprocess that checks if a process runs correctly,
    and if not, prints stdout and stderr.
    """
    proc = subprocess.Popen(args,
                            stdout=subprocess.PIPE,
                            stderr=subprocess.PIPE,
                            cwd=cwd)
    stdout, stderr = proc.communicate()
    if proc.returncode != 0:
        print(stdout.decode())
        print(stderr.decode())
        raise subprocess.CalledProcessError(
            returncode=proc.returncode,
            cmd=args)
    if printOut:
        print(stdout.decode())
        print(stderr.decode())


def install_terraform():
    """Install Terraform."""
    if os.path.exists(TERRAFORM_PATH):
        return

    print(TERRAFORM_PATH)

    urllib.request.urlretrieve(TERRAFORM_DOWNLOAD_URL, '/tmp/terraform.zip')

    check_call(['unzip', '-o', '/tmp/terraform.zip', '-d',
                TERRAFORM_DIR], '/tmp')

    check_call([TERRAFORM_PATH, '--version'])


def handler(event, context):
    print(event)

    if os.path.exists(PROJECT_DIR):
        rmtree(PROJECT_DIR)

    copytree('.', PROJECT_DIR, ignore=ignore_patterns('.terraform',
                                                      'credentials.json'))

    install_terraform()

    check_call([TERRAFORM_PATH, 'init'],
               cwd=PROJECT_DIR,
               printOut=True)
    check_call([TERRAFORM_PATH, 'apply',
               '-target=google_access_context_manager_service_perimeter.service_perimeter', '-no-color',
                '-auto-approve', '-lock=false',
                '-lock-timeout=300s'],
               cwd=PROJECT_DIR,
               printOut=True)
    check_call([TERRAFORM_PATH, 'output', '-json'],
               cwd=PROJECT_DIR,
               printOut=True)