Amazon Web Services auto-scaling setup

aws.py

from boto.ec2.autoscale import AutoScalingGroup, LaunchConfiguration, ScalingPolicy
from boto.ec2.cloudwatch import MetricAlarm

LAUNCH_CONFIG_NAME = 'foo'
AMI_ID = 'your ami id here'
KEY_NAME = 'your key pair name here'
LOAD_BALANCER_NAME = 'your ELB name'
SECURITY_GROUPS = ['security groups here']
AVAILABILITY_ZONES = ['us-east-1a', 'us-east-1b']
INSTANCE_TYPE = 'm1.small' # Type of instance to use for new servers.
GROUP_NAME = 'group name here'

# Stuff to do on boot.
USER_DATA = """#!/bin/sh
/path/to/do_stuff
""".strip()

def set_up_aws():
    lc = LaunchConfiguration(
        name=LAUNCH_CONFIG_NAME,
        image_id=AMI_ID,
        key_name=KEY_NAME,
        security_groups=SECURITY_GROUPS,
        user_data=USER_DATA,
        instance_type=INSTANCE_TYPE,
        instance_monitoring=True,
    )
    conn = boto.connect_autoscale()
    conn.create_launch_configuration(lc)

    ag = AutoScalingGroup(
        group_name=GROUP_NAME,
        load_balancers=[LOAD_BALANCER_NAME],
        availability_zones=AVAILABILITY_ZONES,
        launch_config=lc,
        min_size=2,
        max_size=20,
        connection=conn,
    )
    conn.create_auto_scaling_group(ag)

    scale_up_policy = ScalingPolicy(
        name='scale_up',
        adjustment_type='ChangeInCapacity',
        as_name=GROUP_NAME,
        scaling_adjustment=2,
        cooldown=180,
    )
    conn.create_scaling_policy(scale_up_policy)
    scale_up_policy = conn.get_all_policies(as_group=GROUP_NAME, policy_names=['scale_up'])[0]
    scale_down_policy = ScalingPolicy(
        name='scale_down',
        adjustment_type='ChangeInCapacity',
        as_name=GROUP_NAME,
        scaling_adjustment=-1,
        cooldown=180,
    )
    conn.create_scaling_policy(scale_down_policy)
    scale_down_policy = conn.get_all_policies(as_group=GROUP_NAME, policy_names=['scale_down'])[0]

    cloudwatch = boto.connect_cloudwatch()
    alarm_dimensions = {'AutoScalingGroupName': GROUP_NAME}
    scale_up_alarm = MetricAlarm(
        name='scale_up_on_cpu',
        namespace='AWS/EC2',
        metric='CPUUtilization',
        statistic='Average',
        comparison='>',
        threshold='80',
        period='60', # seconds
        evaluation_periods=2, # How many `period`s it should wait until the alarm is set off.
        alarm_actions=[scale_up_policy.policy_arn],
        dimensions=alarm_dimensions,
    )
    cloudwatch.create_alarm(scale_up_alarm)
    scale_down_alarm = MetricAlarm(
        name='scale_down_on_cpu',
        namespace='AWS/EC2',
        metric='CPUUtilization',
        statistic='Average',
        comparison='<',
        threshold='40',
        period='60', # seconds
        evaluation_periods=2, # How many `period`s it should wait until the alarm is set off.
        alarm_actions=[scale_down_policy.policy_arn],
        dimensions=alarm_dimensions,
    )
    cloudwatch.create_alarm(scale_down_alarm)

via http://www.holovaty.com/writing/aws-notes/

So how did you pass this in as user data when the autoscaling group would trigger a new EC2 instance to join it? Also based on:

Stuff to do on boot.

USER_DATA = """#!/bin/sh
/path/to/do_stuff
""".strip()

How can I pass the latest application release to this autoscaling group from git? I see that you did:
"""

!/bin/sh

su ubuntu
cd /path/to/soundslice/code
git pull
sudo service soundslice start
"""

Do you use virtual env?

HI i am facing an issue whe i have migrated code from my local system to AWS

RawPostDataException at /users/
You cannot access body after reading from request's data stream

It seems i can't access request.method and request.data simulteneously.
Is this specific to AWS?Do i nedd to do some specific config changes to resolve this issue?

It would be great if you can suggest some work around for this issue