create_stack

#!/usr/bin/env python

import argparse
import subprocess
import sys
import os
import boto.cloudformation
import boto.iam
import time
from gen_secrets import gen_password

class KeyValueArgs(argparse.Action):
    def __call__(self, parser, namespace, values, option_string=None):
        if not hasattr(namespace, self.dest):
            setattr(namespace, self.dest, {})

        key, value = values.split('=')
        getattr(namespace, self.dest)[key] = value

class OpsVizStackCreator(object):
    def __init__(self, opts):
        self.opts = opts
        self.iam  = boto.iam.connect_to_region(opts.region)
        self.cf   = boto.cloudformation.connect_to_region(opts.region)

    def gen_certificate(self):
        '''Generates a self-signed cert to be used by
        RabbitMQ'''
        # TODO: provide a way to not have to enter the interactive
        # openssl prompts
        proc = subprocess.Popen(['openssl', 'req', '-new',
                                 '-nodes', '-newkey', 'rsa:2048',
                                 '-x509'], stdout=subprocess.PIPE)

        if proc.wait() != 0:
            raise SystemExit("Failed to generate self-signed OpenSSL")

        return (self.get_privkey(),  proc.stdout.read())

    def get_privkey(self):
        '''When the -newkey option is given to req, it writes the key
        to a file named "privkey.pem". We want to read the key from
        that file and the clean it up'''
        # this is required to make the java library on the
        # recieving end happy
        privkey = subprocess.check_output([
            'openssl', 'rsa', '-in', 'privkey.pem'])

        try:
            os.unlink('privkey.pem')
        except OSError:
            sys.stderr.write("WARNING: failed to delete privkey.pem\n")

        return privkey

    def upload_cert(self):
        '''Uploads a cert and key to IAM and return the ARN of the
        uploaded cert'''

        resp = self.iam.upload_server_cert(
            cert_name="{}_cert".format(self.opts.stack_name),
            cert_body=self.ssl_cert,
            private_key=self.ssl_key)

        try:
            return resp['upload_server_certificate_response']['upload_server_certificate_result']['server_certificate_metadata']['arn']
        except KeyError:
            raise SystemExit("Failed to get ARN from cert upload. Resp: {}".format(resp))

    def prepare_cert(self):
        self.ssl_key, self.ssl_cert = self.gen_certificate()
        self.cert_arn = self.upload_cert()

        return self.cert_arn

    def gen_cf_params(self):
        params = {
            'RabbitMQSensuPassword': gen_password(),
            'RabbitMQStatsdPassword': gen_password(),
            'RabbitMQLogstashExternalPassword': gen_password(),
            'RabbitMQLogstashInternalPassword': gen_password(),
            'RabbitMQErlangCookie': gen_password(50),
            'RabbitMQCertificateARN': self.cert_arn,
            'DoormanSessionSecret': gen_password(50)
        }

        #user provided params override whatever we generate or set
        #as a default
        params.update(self.opts.params)

        return params

    def read_template(self):
        with open('cloudformation.json', 'r') as fh:
            return fh.read()

    def spin_up(self, params):
        print "Creating stack with params: "
        print params

        stack_id = self.cf.create_stack(
            stack_name=self.opts.stack_name,
            template_body=self.read_template(),
            capabilities=['CAPABILITY_IAM'],
            parameters=params.items(),
            disable_rollback=True
        )

        #events we have already printed out
        reported_events = set()
        stack = self.cf.describe_stacks(stack_id)[0]

        while stack.stack_status == 'CREATE_IN_PROGRESS':
            all_events = set(stack.describe_events())
            for event in reported_events - all_events:
                print event

            reported_events = all_events
            time.sleep(5)
            stack.update()

        if not stack.stack_status == 'CREATE_COMPLETE':
            raise SystemExit("Stack creation failed")
        else:
            print "Stack creation completed"

    def create_stack(self):
        self.prepare_cert()
        self.spin_up(self.gen_cf_params())

def get_args():
    parser = argparse.ArgumentParser(description='Create an OpsViz stack')
    parser.add_argument('--region', default='us-east-1',
                        help='AWS region. Default: us-east-1')
    parser.add_argument('stack_name',
                        help='CloudFormation stack name. Must be unique')
    parser.add_argument('--dry-run', action='store_true',
                        help='Generate params and display them,' +
                        'but does not spin up the stack')
    parser.add_argument('--cookbook-repo', '-c',
                        help="The git url for your custom cookbooks")
    parser.add_argument('--param', dest='params', action=KeyValueArgs,
                        default={},
                        help="Override additional params in the form of key=value. Can be specified multiple times")

    args = parser.parse_args()

    if not args.cookbook_repo:
        raise SystemExit("A cookbook repo is required")

    if not args.stack_name:
        raise SystemExit("A stack name is required")

    #Add the cookbook to the list of user params. The cookbook
    #is only provided stand-alone because it is required
    args.params['CookbooksRepo'] = args.cookbook_repo

    return args

def main():
    args = get_args()
    stack_creator = OpsVizStackCreator(args)
    stack_creator.create_stack()

if __name__ == '__main__':
    main()