helloworld-cf-template.py

"""Generating CloudFormation template."""

from ipaddress import ip_network
from ipify import get_ip

from troposphere import (Base64,

                         ec2,
                         GetAtt,
                         Join,
                         Output,
                         Parameter,
                         Ref,
                         Template)

ApplicationPort = "3000"
PublicCidrIp = str(ip_network(get_ip()))

t = Template()

t.add_description("Effective DevOps in AWS: HelloWorld web application")

t.add_parameter(Parameter("KeyPair",
                          Description="Name of an existing EC2 KeyPair to SSH",
                          Type="AWS::EC2::KeyPair::KeyName",
                          ConstraintDescription="must be the name of an existing EC2 KeyPair.", ))

t.add_resource(ec2.SecurityGroup(
    "SecurityGroup",
    GroupDescription="Allow SSH and TCP/{} access".format(ApplicationPort),
    SecurityGroupIngress=[
        ec2.SecurityGroupRule(
            IpProtocol="tcp",
            FromPort="22",
            ToPort="22",
            CidrIp=PublicCidrIp, ),
        ec2.SecurityGroupRule(
            IpProtocol="tcp",
            FromPort=ApplicationPort,
            ToPort=ApplicationPort,
            CidrIp="0.0.0.0/0", ), ], ))

ud = Base64(Join('\n', [
    "#!/bin/bash",
    "sudo yum install --enablerepo=epel -y nodejs",
    "wget http://bit.ly/2vESNuc -O /home/ec2-user/helloworld.js",
    "wget http://bit.ly/2vVvT18 -O /etc/init/helloworld.conf",
    "start helloworld"]))

instance = ec2.Instance(
    "instance",
    ImageId="ami-ff4ea59d",
    InstanceType="t2.micro",
    SecurityGroups=[Ref("SecurityGroup")],
    KeyName=Ref("KeyPair"),
    UserData=ud, )

t.add_resource(instance)

t.add_output(Output(
    "InstancePublicIp",
    Description="Public IP of our instance.",
    Value=GetAtt(instance, "PublicIp"), ))
t.add_output(Output(
    "WebUrl",
    Description="Application endpoint",
    Value=Join("", ["http://", GetAtt(instance, "PublicDnsName"), ":", ApplicationPort]), ))

print(t.to_json())