{
    "AWSTemplateFormatVersion" : "2010-09-09",

    "Description" : "Runs a VNC server fleet that binds instances to domain names.",

    "Parameters" : {
        "KeyName" : {
            "Description" : "Name of an existing EC2 KeyPair to enable SSH access to the instances",
            "Type" : "String"
        },
        "InstanceType" : {
            "Description" : "VNC host instance type",
            "Type" : "String",
            "Default" : "t1.micro",
            "AllowedValues" : [ "t1.micro","m1.small","m1.medium","m1.large","m1.xlarge","m2.xlarge","m2.2xlarge","m2.4xlarge","m3.xlarge","m3.2xlarge","c1.medium","c1.xlarge","cc1.4xlarge","cc2.8xlarge","cg1.4xlarge"],
            "ConstraintDescription" : "must be a valid EC2 instance type."
        },
        "MinSize" : {
            "Description" : "Minimum number of VNC hosts",
            "Type" : "Number",
            "MinValue" : "1",
            "Default" : "1",
            "ConstraintDescription" : "Must have at least one host"
        },
        "MaxSize" : {
            "Description" : "Maximum number of VNC hosts",
            "Type" : "Number",
            "MinValue" : "1",
            "Default" : "1",
            "ConstraintDescription" : "Must have at least one host"
        },
        "SSHLocation" : {
            "Description" : "The IP address range that can be used to SSH into hosts",
            "Type": "String",
            "MinLength": "9",
            "MaxLength": "18",
            "Default": "0.0.0.0/0",
            "AllowedPattern": "(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})/(\\d{1,2})",
            "ConstraintDescription": "must be a valid IP CIDR range of the form x.x.x.x/x."
        },
        "HostedZoneId" : {
            "Description" : "The Hosted Zone Id to use when assigning DNS mappings",
            "Type" : "String"
        },
        "DNSProcessorServiceToken" : {
            "Description" : "ServiceToken of DNS Processor Custom Resource",
            "Type" : "String",
            "AllowedPattern" : "arn:aws:sns:.*",
            "ConstraintDescription" : "must be an SNS topic ARN"
        }
    },

    "Mappings" : {
        "AwsRegionToAMI" : {
            "ap-northeast-1" : { "id" : "ami-6dea746c" },
            "ap-southeast-1" : { "id" : "ami-141d5746" },
            "ap-southeast-2" : { "id" : "ami-f377eac9" },
            "eu-west-1" :      { "id" : "ami-5e03e429" },
            "us-east-1" :      { "id" : "ami-ad83d7c4" },
            "us-west-1" :      { "id" : "ami-7e37033b" },
            "us-west-2" :      { "id" : "ami-12fe6022" },
            "sa-east-1" :      { "id" : "ami-ed47e0f0" }
        }
    },

    "Resources" : {
        "DNSProcessor" : {
            "Type" : "Custom::DNSProcessor",
            "Version" : "1.0",
            "Properties" : {
                "ServiceToken" : { "Ref" : "DNSProcessorServiceToken" },
                "DNSPattern" : { "Fn::Join" : [".", ["{{simpsons_name}}", { "Ref" : "AWS::Region" }, "{{hosted_zone_name}}"]] },
                "HostedZoneId" : { "Ref" : "HostedZoneId" }
            }
        },

        "VncLaunchConfig" : {
            "Type" : "AWS::AutoScaling::LaunchConfiguration",
            "Properties" : {
                "ImageId" : { "Fn::FindInMap" : ["AwsRegionToAMI", { "Ref" : "AWS::Region" }, "id"] },
                "InstanceType" : { "Ref" : "InstanceType" },
                "KeyName" : { "Ref" : "KeyName" },
                "SecurityGroups" : [ { "Ref" : "VncSecurityGroup" } ],
                "UserData" : { "Fn::Base64" : { "Fn::Join" : ["", [
                    "#!/bin/bash -x\n",
                    "exec &> /home/ubuntu/userdata.log\n",
                    "function error_exit\n",
                    "{\n",
                    "  cfn-signal -e 1 -r \"$1\" '", { "Ref" : "VncWaitConditionHandle" }, "'\n",
                    "  exit 1\n",
                    "}\n",
                    "apt-get update || error_exit 'Failed to update package repository'\n",
                    "apt-get -y install python-pip || error_exit 'Failed to install python-pip'\n",
                    "pip install https://s3.amazonaws.com/cloudformation-examples/aws-cfn-bootstrap-latest.tar.gz\n",
                    "cfn-init --region ", { "Ref" : "AWS::Region" }, " -s ", { "Ref" : "AWS::StackName" }, " -r VncLaunchConfig || error_exit 'Failed to run cfn-init'\n",
                    "/etc/init.d/vncserver start || error_exit 'Failed to start vnc server'\n",
                    "cfn-signal -e $? ", { "Fn::Base64" : { "Ref" : "VncWaitConditionHandle" }}, "\n"
                ]] } }
            },
            "Metadata" : {
                "AWS::CloudFormation::Init" : {
                    "config" : {
                        "packages" : {
                            "apt" : {
                                "tightvncserver" : [],
                                "fluxbox" : []
                            }
                        },
                        "files" : {
                            "/etc/init.d/vncserver" : {
                                "content" : { "Fn::Join" : ["\n", [
                                    "#!/bin/sh -e",
                                    "### BEGIN INIT INFO",
                                    "# Provides: vncserver",
                                    "# Required-Start: networking",
                                    "# Default-Start: S",
                                    "# Default-Stop: 0 6",
                                    "### END INIT INFO",
                                    "export USER=\"ubuntu\"",
                                    "OPTIONS=\"-depth 16 -geometry 1024x768 :1\"",

                                    ". /lib/lsb/init-functions",

                                    "case \"$1\" in",
                                    "start)",
                                    "su ${USER} -c \"/usr/bin/vncserver ${OPTIONS}\"",
                                    ";;",

                                    "stop)",
                                    "su ${USER} -c \"/usr/bin/vncserver -kill :1\"",
                                    ";;",
                                    "restart)",
                                    "su ${USER} -c \"/usr/bin/vncserver -kill :1\"",
                                    "su ${USER} -c \"/usr/bin/vncserver ${OPTIONS}\"",
                                    ";;",
                                    "esac"
                                ]]},
                                "owner" : "root",
                                "group" : "root",
                                "mode" : "000755"

                            },
                            "/home/ubuntu/.vnc/passwd" : {
                                "content" : "X6670O8KJBM=",
                                "encoding" : "base64",
                                "mode" : "000600",
                                "owner" : "ubuntu",
                                "group" : "ubuntu"
                            },
                            "/home/ubuntu/.vnc/xstartup" : {
                                "content" : { "Fn::Join" : ["\n", [
                                    "#!/bin/sh",
                                    "xrdb $HOME/.Xresources",
                                    "xsetroot -solid grey",
                                    "/usr/bin/startfluxbox &",
                                    "# Fix to make GNOME work",
                                    "export XKL_XMODMAP_DISABLE=1",
                                    "/etc/X11/Xsession"
                                ]]},
                                "mode" : "000755",
                                "owner" : "ubuntu",
                                "group" : "ubuntu"
                            }
                        },
                        "commands" : {
                            "01-start-vnc-on-boot": {
                                "command" : "update-rc.d vncserver defaults"
                            },
                            "02-change-ownership-of-.vnc": {
                                "command" : "chown ubuntu:ubuntu /home/ubuntu/.vnc"
                            },
                            "03-set-permissions-of-.vnc": {
                                "command" : "chmod 700 /home/ubuntu/.vnc"
                            }
                        }
                    }
                }
            }
        },

        "VncAutoScalingGroup" : {
            "Type" : "AWS::AutoScaling::AutoScalingGroup",
            "Properties" : {
                "AvailabilityZones" : { "Fn::GetAZs" : ""},
                "LaunchConfigurationName" : { "Ref" : "VncLaunchConfig" },
                "MinSize" : { "Ref" : "MinSize" },
                "MaxSize" : { "Ref" : "MaxSize" },
                "NotificationConfiguration" : {
                    "TopicARN" : { "Fn::GetAtt" : ["DNSProcessor", "Topic"] },
                    "NotificationTypes" : [ "autoscaling:EC2_INSTANCE_LAUNCH","autoscaling:EC2_INSTANCE_TERMINATE"]
                },
                "Tags" : [
                    {
                        "Key" : "ProcessorId",
                        "Value" : { "Ref" : "DNSProcessor" },
                        "PropagateAtLaunch" : false
                    }
                ]
            }
        },

        "VncSecurityGroup" : {
            "Type" : "AWS::EC2::SecurityGroup",
            "Properties" : {
                "GroupDescription" : "SSH to the vnc instances",
                "SecurityGroupIngress" : [
                    {
                        "CidrIp" : { "Ref" : "SSHLocation" },
                        "FromPort" : "22",
                        "ToPort" : "22",
                        "IpProtocol" : "tcp"
                    }
                ]
            }
        },

        "VncWaitConditionHandle" : {
            "Type" : "AWS::CloudFormation::WaitConditionHandle"
        },

        "VncWaitCondition" : {
            "Type" : "AWS::CloudFormation::WaitCondition",
            "DependsOn" : "VncAutoScalingGroup",
            "Properties" : {
                "Count" : { "Ref" : "MinSize"},
                "Handle" : { "Ref" : "VncWaitConditionHandle" },
                "Timeout" : "600"
            }
        }
    },

    "Outputs" : {
        "SecurityGroup" : {
            "Description" : "Security group of the vnc hosts",
            "Value" : { "Ref" : "VncSecurityGroup" }
        }
    }
}