#!/usr/bin/env python
# Copyright (c) 2011 Joel Barciauskas http://joel.barciausk.as/
#
# Permission is hereby granted, free of charge, to any person obtaining a
# copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish, dis-
# tribute, sublicense, and/or sell copies of the Software, and to permit
# persons to whom the Software is furnished to do so, subject to the fol-
# lowing conditions:
#
# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
# OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABIL-
# ITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
# SHALL THE AUTHOR BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS

#
# Auto Scaling Groups Tool
#
VERSION="0.1"
usage = """%prog [options] [command]
Commands:
    list|ls                           List all Auto Scaling Groups
    list-lc|ls-lc                     List all Launch Configurations
    delete    <name>                  Delete ASG <name>
    delete-lc <name>                  Delete Launch Configuration <name>
    get       <name>                  Get details of ASG <name>
    create    <name>                  Create an ASG
    create-lc <name>                  Create a Launch Configuration
    update    <name> <prop> <value>   Update a property of an ASG
    update-image <asg-name> <lc-name> Update image ID for ASG by creating a new LC
    migrate-instances <name>          Shut down current instances one by one and wait for ASG to start up a new instance with the current AMI (useful in conjunction with update-image)

Examples:

    1) Create launch configuration
        bin/asadmin create-lc my-lc-1 -i ami-1234abcd -t c1.xlarge -k my-key -s web-group -m

    2) Create auto scaling group in us-east-1a and us-east-1c with a load balancer and min size of 2 and max size of 6
        bin/asadmin create my-asg -z us-east-1a -z us-east-1c -l my-lc-1 -b my-lb -H ELB -p 180 -x 2 -X 6
"""

def get_group(autoscale, name):
    g = autoscale.get_all_groups(names=[name])
    if len(g) < 1:
        print "No auto scaling groups by the name of %s found" % name
        return sys.exit(1)
    return g[0]

def get_lc(autoscale, name):
    l = autoscale.get_all_launch_configurations(names=[name])
    if len(l) < 1:
        print "No launch configurations by the name of %s found" % name
        sys.exit(1)
    return l[0]

def list(autoscale):
    """List all ASGs"""
    print "%-20s %s" %  ("Name", "LC Name")
    print "-"*80
    groups = autoscale.get_all_groups()
    for g in groups:
        print "%-20s %s" % (g.name, g.launch_config_name)

def list_lc(autoscale):
    """List all LCs"""
    print "%-30s %-20s %s" %  ("Name", "Image ID", "Instance Type")
    print "-"*80
    for l in autoscale.get_all_launch_configurations():
        print "%-30s %-20s %s" % (l.name, l.image_id, l.instance_type)

def get(autoscale, name):
    """Get details about ASG <name>"""
    g = get_group(autoscale, name)
    print "="*80
    print "%-30s %s" % ('Name:', g.name)
    print "%-30s %s" % ('Launch configuration:', g.launch_config_name)
    print "%-30s %s" % ('Minimum size:', g.min_size)
    print "%-30s %s" % ('Maximum size:', g.max_size)
    print "%-30s %s" % ('Desired capacity:', g.desired_capacity)
    print "%-30s %s" % ('Load balancers:', ','.join(g.load_balancers))

    print

    print "Instances"
    print "---------"
    print "%-20s %-20s %-20s %s" % ("ID", "Status", "Health", "AZ")
    for i in g.instances:
        print "%-20s %-20s %-20s %s" % \
        (i.instance_id, i.lifecycle_state, i.health_status, i.availability_zone)

    print

def create(autoscale, name, zones, lc_name, load_balancers, hc_type, hc_period,
        min_size, max_size, cooldown, capacity):
    """Create an ASG named <name>"""
    g = AutoScalingGroup(name=name, launch_config=lc_name,
            availability_zones=zones, load_balancers=load_balancers,
            default_cooldown=cooldown, health_check_type=hc_type,
            health_check_period=hc_period, desired_capacity=capacity,
            min_size=min_size, max_size=max_size)
    g = autoscale.create_auto_scaling_group(g)
    return list(autoscale)

def create_lc(autoscale, name, image_id, instance_type, key_name,
        security_groups, instance_monitoring):
    l = LaunchConfiguration(name=name, image_id=image_id,
            instance_type=instance_type,key_name=key_name,
            security_groups=security_groups,
            instance_monitoring=instance_monitoring)
    l = autoscale.create_launch_configuration(l)
    return list_lc(autoscale)

def update(autoscale, name, prop, value):
    g = get_group(autoscale, name)
    setattr(g, prop, value)
    g.update()
    return get(autoscale, name)

def delete(autoscale, name, force_delete=False):
    """Delete this ASG"""
    g = get_group(autoscale, name)
    autoscale.delete_auto_scaling_group(g.name, force_delete)
    print "Auto scaling group %s deleted" % name
    return list(autoscale)

def delete_lc(autoscale, name):
    """Delete this LC"""
    l = get_lc(autoscale, name)
    autoscale.delete_launch_configuration(name)
    print "Launch configuration %s deleted" % name
    return list_lc(autoscale)

def update_image(autoscale, name, lc_name, image_id, is_migrate_instances=False):
    """ Get the current launch config,
        Update its name and image id
        Re-create it as a new launch config
        Update the ASG with the new LC
        Delete the old LC """

    g = get_group(autoscale, name)
    l = get_lc(autoscale, g.launch_config_name)

    old_lc_name = l.name
    l.name = lc_name
    l.image_id = image_id
    autoscale.create_launch_configuration(l)
    g.launch_config_name = l.name
    g.update()

    if(is_migrate_instances):
        migrate_instances(autoscale, name)
    else:
        return get(autoscale, name)

def migrate_instances(autoscale, name):
    """ Shut down instances of the old image type one by one
        and let the ASG start up instances with the new image """
    g = get_group(autoscale, name)

    old_instances = g.instances
    ec2 = boto.connect_ec2()
    for old_instance in old_instances:
        print "Terminating instance " + old_instance.instance_id
        ec2.terminate_instances([old_instance.instance_id])
        while True:
            g = get_group(autoscale, name)
            new_instances = g.instances
            for new_instance in new_instances:
                hasOldInstance = False
                instancesReady = True
                if(old_instance.instance_id == new_instance.instance_id):
                    hasOldInstance = True
                    print "Waiting for old instance to shut down..."
                    break
                elif(new_instance.lifecycle_state != 'InService'):
                    instancesReady = False
                    print "Waiting for instances to be ready...."
                    break
            if(not hasOldInstance and instancesReady):
                break
            else:
                time.sleep(20)
    return get(autoscale, name)

if __name__ == "__main__":
    try:
        import readline
    except ImportError:
        pass
    import boto
    import sys
    import time
    from optparse import OptionParser
    from boto.mashups.iobject import IObject
    from boto.ec2.autoscale import AutoScalingGroup
    from boto.ec2.autoscale import LaunchConfiguration
    parser = OptionParser(version=VERSION, usage=usage)
    """ Create launch config options """
    parser.add_option("-i", "--image-id",
            help="Image (AMI) ID", action="store",
            type="string", default=None, dest="image_id")
    parser.add_option("-t", "--instance-type",
            help="EC2 Instance Type (e.g., m1.large, c1.xlarge), default is m1.large",
            action="store", type="string", default="m1.large", dest="instance_type")
    parser.add_option("-k", "--key-name",
            help="EC2 Key Name",
            action="store", type="string", dest="key_name")
    parser.add_option("-s", "--security-group",
            help="EC2 Security Group",
            action="append", default=[], dest="security_groups")
    parser.add_option("-m", "--monitoring",
            help="Enable instance monitoring",
            action="store_true", default=False, dest="instance_monitoring")

    """ Create auto scaling group options """
    parser.add_option("-z", "--zone", help="Add availability zone", action="append", default=[], dest="zones")
    parser.add_option("-l", "--lc-name",
            help="Launch configuration name",
            action="store", default=None, type="string", dest="lc_name")
    parser.add_option("-b", "--load-balancer",
            help="Load balancer name",
            action="append", default=[], dest="load_balancers")
    parser.add_option("-H", "--health-check-type",
            help="Health check type (EC2 or ELB)",
            action="store", default="EC2", type="string", dest="hc_type")
    parser.add_option("-p", "--health-check-period",
            help="Health check period in seconds (default 300s)",
            action="store", default=300, type="int", dest="hc_period")
    parser.add_option("-X", "--max-size",
            help="Max size of ASG (default 10)",
            action="store", default=10, type="int", dest="max_size")
    parser.add_option("-x", "--min-size",
            help="Min size of ASG (default 2)",
            action="store", default=2, type="int", dest="min_size")
    parser.add_option("-c", "--cooldown",
            help="Cooldown time after a scaling activity in seconds (default 300s)",
            action="store", default=300, type="int", dest="cooldown")
    parser.add_option("-C", "--desired-capacity",
            help="Desired capacity of the ASG",
            action="store", default=None, type="int", dest="capacity")
    parser.add_option("-f", "--force",
            help="Force delete ASG",
            action="store_true", default=False, dest="force")
    parser.add_option("-y", "--migrate-instances",
            help="Automatically migrate instances to new image when running update-image",
            action="store_true", default=False, dest="migrate_instances")

    (options, args) = parser.parse_args()

    if len(args) < 1:
        parser.print_help()
        sys.exit(1)

    autoscale = boto.connect_autoscale()

    print "%s" % (autoscale.region.endpoint)

    command = args[0].lower()
    if command in ("ls", "list"):
        list(autoscale)
    elif command in ("ls-lc", "list-lc"):
        list_lc(autoscale)
    elif command == "get":
        get(autoscale, args[1])
    elif command == "create":
        create(autoscale, args[1], options.zones, options.lc_name,
                options.load_balancers, options.hc_type,
                options.hc_period, options.min_size, options.max_size,
                options.cooldown, options.capacity)
    elif command == "create-lc":
        create_lc(autoscale, args[1], options.image_id, options.instance_type,
                options.key_name, options.security_groups,
                options.instance_monitoring)
    elif command == "update":
        update(autoscale, args[1], args[2], args[3])
    elif command == "delete":
        delete(autoscale, args[1], options.force)
    elif command == "delete-lc":
        delete_lc(autoscale, args[1])
    elif command == "update-image":
        update_image(autoscale, args[1], args[2],
                options.image_id, options.migrate_instances)
    elif command == "migrate-instances":
        migrate_instances(autoscale, args[1])
