demo.py

import os
import sys
import time
from os.path import join as pjoin

import warnings
warnings.filterwarnings('ignore')

sys.path.insert(0, '/Users/kami/Projects/Programming/Python/libcloud-trunk')

import libcloud.security
libcloud.security.VERIFY_SSL_CERT = True

from libcloud.compute.types import Provider as ProviderCompute
from libcloud.compute.providers import get_driver as get_driver_compute

from libcloud.storage.types import Provider as ProviderStorage
from libcloud.storage.providers import get_driver as get_driver_storage

from libcloud.resource.lb.types import Provider as ProviderLb
from libcloud.resource.lb.providers import get_driver as get_driver_lb

from libcloud.compute.types import NodeState
from libcloud.resource.lb.base import LBNode
from libcloud.storage.types import ContainerAlreadyExistsError

import secrets

SLEEP = 5
SIZE_ID = 't1.micro'
IMAGE_ID = 'ami-f5bfefb0'
NODE_NAME_PREFIX = 'libcloud-demo'

CONTAINER_NAME = 'demo_app'
APP_FILE = 'hello.js'

BALANCER_NAME = 'demo_lb'

conn_ec2 = get_driver_compute(ProviderCompute.EC2_US_WEST)(secrets.EC2_ACCESS_ID,
                                                           secrets.EC2_SECRET_KEY)
conn_cf = get_driver_storage(ProviderStorage.CLOUDFILES_US)(secrets.CF_USERNAME,
                                                            secrets.CF_API_KEY)
conn_rs = get_driver_lb(ProviderLb.RACKSPACE)(secrets.CF_USERNAME,
                                                        secrets.CF_API_KEY)

def upload_app(app_path):
  print '-> Uploading app to CloudFiles'
  try:
    container = conn_cf.create_container(container_name=CONTAINER_NAME)
    container.enable_cdn()
  except ContainerAlreadyExistsError:
    container = conn_cf.get_container(container_name=CONTAINER_NAME)
  obj = container.upload_object(file_path=app_path, object_name=APP_FILE)
  return obj

def boot_and_setup_nodes(number, app_url):
  print '-> Booting %d nodes on EC2' % (number)
  nodes = []
  size = [size for size in conn_ec2.list_sizes() if
           size.id == SIZE_ID][0]
  image = [image for image in conn_ec2.list_images() if
            image.id == IMAGE_ID][0]

  script_content = open('script.sh').read()
  for index in range(0, number):
    name = '%s-%d' % (NODE_NAME_PREFIX, index + 1)
    script = script_content % {'app_url': app_url, 'server': name,
                               'app_file': APP_FILE}
    node = conn_ec2.create_node(name=name, size=size, image=image,
                                ex_userdata=script, ex_keyname='libcloud_demo')
    nodes.append(node)

  print '-> %d nodes created' % (number)
  return nodes

def setup_load_balancers(nodes):
  print '-> Creating load balancer at Rackspace'
  lb_nodes = []
  for node in nodes:
    lb_nodes.append(LBNode(id=node.id, ip=node.public_ip[0], port=80))
  print lb_nodes
  balancer = conn_rs.create_balancer(name=BALANCER_NAME, port=80, nodes=lb_nodes)

  print '-> Balancer created and all the nodes attached'
  print '-> Balancer is listening on http://%s:%s' % (balancer.ip, balancer.port)
  return balancer

def wait_until_running(expected):
  print '-> Waiting for all nodes to become active'
  running = []
  nodes = conn_ec2.list_nodes()

  while len(running) != expected:
    for node in nodes:
      if node.state == NodeState.RUNNING and node not in running:
        running.append(node)

      if len(running) == expected:
        return running

    nodes = conn_ec2.list_nodes()
    print 'Not all nodes yet active, sleeping %d seconds...' % (SLEEP)
    time.sleep(SLEEP)
  return running

def main():
  obj = upload_app(pjoin(os.getcwd(), APP_FILE))
  obj_cdn_url = obj.get_cdn_url()
  boot_and_setup_nodes(number=2, app_url=obj_cdn_url)
  nodes = wait_until_running(expected=2)
  balancer = setup_load_balancers(nodes)

if __name__ == '__main__':
  main()