Create Environment Variables in EC2 Hosts from EC2 Host Tags, just like Beanstalk or Heroku does!

ec2-host-from-tag-to-env-vars.sh

######
# Author: Chris Frisina from Marcello de Sales (marcello.desales@gmail.com)
# Description: Create Environment Variables in EC2 Hosts from EC2 Host Tags
# 
### Requirements:  
#
### Installation:
# * Add the Policy EC2:DescribeTags to a User (https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/iam-policies-ec2-console.html)
# * aws configure 
# * Source it to the user's ~/.profile that has permissions
#### 
# Add tags to an EC2 host or Image Profile
# Reboot and verify the result of $(env).

# Loads the Tags from the current instance
getInstanceTags () {
    INSTANCE_ID=$(curl -s http://169.254.169.254/latest/meta-data/instance-id)
    EC2_AVAIL_ZONE=`curl -s http://169.254.169.254/latest/meta-data/placement/availability-zone`
    EC2_REGION="`echo \"$EC2_AVAIL_ZONE\" | sed -e 's:\([0-9][0-9]*\)[a-z]*\$:\\1:'`"

    # Print tags as 'export TAG_Key="Value"'
    aws ec2 describe-tags --region $EC2_REGION --filters "Name=resource-id,Values=$INSTANCE_ID" | \
      python -c "import sys,json; map(lambda t: sys.stdout.write('export TAG_%s=\"%s\"\n' % (t['Key'], t['Value'])), json.load(sys.stdin)['Tags'])"
}

# Export variables from tags
$(getInstanceTags)