Get EC2 instance type

instance.py

#!/usr/bin/env python
# Get CPU (core number) and memory by instance_type
# usage: python instance.py (INSANCE_TYPE|VCPU MEMORY)

import json
import sys
import urllib2


JSON_URL = 'https://raw.githubusercontent.com/powdahound/ec2instances.info/master/www/instances.json'
JSON_FILE = urllib2.urlopen(JSON_URL)
STREAM = sys.stdout


def get_metrics(instance_type):
    """
    Get metrics by instance type

    :param str instance_type: instance type
    """
    s = JSON_FILE.read()
    j = json.loads(s)
    for instance in j:
        if instance['instance_type'] == instance_type:
            return '%d %.2f' % (instance['vCPU'], instance['memory'])


def get_instance_types(v_cpu, memory):
    """
    Get instance type by metrics

    :param tuple metrics: a 2-tuple of vCPU and memory
    """
    v_cpu = int(v_cpu)
    memory = float(memory)
    s = JSON_FILE.read()
    j = json.loads(s)
    res = []
    for instance in j:
        if instance['vCPU'] == v_cpu and instance['memory'] == memory:
            res.append(instance['instance_type'])
    return res


if __name__ == '__main__':
    if len(sys.argv) >= 2:
        if len(sys.argv) == 2:
            instance_type = sys.argv[1]
            STREAM.write(get_metrics(instance_type) + '\n')
        elif len(sys.argv) == 3:
            v_cpu = sys.argv[1]
            memory = sys.argv[2]
            res = get_instance_types(v_cpu, memory)
            res_s = '\n'.join(res)
            STREAM.write(res_s + '\n')
    else:
        STREAM.write('No argument given.\n')
        sys.exit(1)