Fab tasks for AWS setup

gistfile1.py

from fabric import api as fab
import boto

LOAD_BALANCER_NAME = 'my elb name'
SERVER_USER = 'serverusername'
SSH_KEY_FILE = '/path/to/mykey.pem'

def aws_hosts():
    # This assumes your bash_profile has AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY set.

    # Get a list of instance IDs for the ELB.
    instances = []
    conn = boto.connect_elb()
    for elb in conn.get_all_load_balancers(LOAD_BALANCER_NAME):
        instances.extend(elb.instances)

    # Get the instance IDs for the reservations.
    conn = boto.connect_ec2()
    reservations = conn.get_all_instances([i.id for i in instances])
    instance_ids = []
    for reservation in reservations:
        for i in reservation.instances:
            instance_ids.append(i.id)

    # Get the public CNAMES for those instances.
    hosts = []
    for host in conn.get_all_instances(instance_ids):
        hosts.extend([i.public_dns_name for i in host.instances])
    hosts.sort() # Put them in a consistent order, so that calling code can do hosts[0] and hosts[1] consistently.

    return hosts

def aws():
    fab.env.hosts = aws_hosts()
    fab.env.key_filename = SSH_KEY_FILE
    fab.env.user = SERVER_USER
    fab.env.parallel = True

def update_code():
    with fab.cd('/opt/code/myapp'):
        fab.run('git pull')

def deploy():
    update_code()
    fab.run('sudo service gunicorn restart')