lambda for ec2 info

var AWS = require('aws-sdk');  
AWS.config.region = 'us-east-1';  

function validInstance(instance) {
    return instance.SecurityGroups[0] && 
        instance.SecurityGroups[0].GroupName === 'ctf_instance' && 
        instance.State.Code == 16 &&
        instance.Tags[0]
}

function getInstances(data) {
    return data.Reservations.map(function(reservation) {
           return reservation.Instances.filter(function(instance) {
               return validInstance(instance)
           }).map(function(instance) {
               return instance.Tags[0].Value + ":" + instance.PrivateIpAddress
            })
    }).filter(function(result) {
        return result.length > 0 && result !== null
    })
}

exports.handler = function(event, context) {  
    var ec2 = new AWS.EC2();
    ec2.describeInstances(function(err, data) {
        if (err) context.done(err, err.stack);
        else context.done(null, getInstances(data))
    })
};