#!/usr/bin/php
<?php

/**
 * This script sets up a proxy based on an Amazon EC2 instance. It starts an
 * Amazon EC2 instance, installs TinyProxy and sets up an SSH tunnel to the 
 * machine.
 * 
 * USAGE             Make executable, then use like: $ ec2-proxy (start|stop)
 * REQUIREMENTS      - Amazon AWS account, X.509 certificate, EC2 private key
 *                   - Amazon API tools installed (ec2-api-tools)
 *
 * AUTHOR            Philipp C. Heckel
 * WEBSITE           http://blog.philippheckel.com/2012/06/15/script-your-us-proxy-server-in-two-minutes-using-amazon-ec2/
 * SCRIPT VERSION    Version 2 (June 2014)
 */

/// CONFIG /////////////////////////////////////////////////////////////////////

// AMI options
$AMI           = "ami-018c9568";               // AMI name; default value is 'ami-ac9943c5', Ubuntu 12.04 32-bit EBS, micro
                                               // More Ubuntu AMIs at: http://uec-images.ubuntu.com/releases/
$PARAMS        = "--instance-type t1.micro";   // Additional params for the 'ec2-run-instances' command.
$LOGIN         = "ubuntu";                     // SSH login name for the above AMI image (for Ubuntu: 'ubuntu')

// Other options
$LOCAL_PORT    = 8888;                         // Port of the local SOCKS proxy (connect your browser to localhost:$LOCAL_PORT)


/// MAIN SCRIPT /////////////////////////////////////////////////////////////////

if (!getenv("AWS_ACCESS_KEY") || !getenv("AWS_SECRET_KEY") || !getenv("AWS_KEYPAIR_NAME") || !getenv("AWS_KEYPAIR_FILE")) {
	die("ERROR: AWS_ACCESS_KEY, AWS_SECRET_KEY, AWS_KEYPAIR_NAME and AWS_KEYPAIR_FILE must be set.\n");
}

$AWS_KEYPAIR_NAME = getenv("AWS_KEYPAIR_NAME"); 
$AWS_KEYPAIR_FILE = getenv("AWS_KEYPAIR_FILE"); 

// Wrong usage, show help
if (count($argv) == 1) {
	showUsage();
}

// OPTION 'start'
if ($argv[1] == "start") {
	$machine = findInstance();

	// Not running
	if (!$machine) {
		// Do run via 'ec2-run-instances' and parse output for INSTANCE
		echo "[".date("H:i:s")."] Launching instance of AMI $AMI ... ";
		$out = `ec2-run-instances -k "$AWS_KEYPAIR_NAME" $AMI $PARAMS`;
		
		if (!preg_match("/INSTANCE	(\S+)/s",$out,$m)) {
			die("Invalid output from ec2-run-instances command:\n$out");
		}

		$instance = $m[1];
		echo "Launched instance $instance\n";

		// Run 'ec2-describe-instances' until we're ready
		echo "[".date("H:i:s")."] Waiting until ready ...";

		while (!($machine = findInstance($instance,true))) {
			echo ".";
		}
			
		echo " Running at {$machine['dns']}\n";		
	}
	
	// Test SSH by trying to login repeatedly with the private key
	// and writing OKAY on the console. Then parse the output for the OKAY
	echo "[".date("H:i:s")."] Testing SSH ...";
	while (true) {
		sleep(1);
		$out = `ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no $LOGIN@{$machine['dns']} -i "$AWS_KEYPAIR_FILE" echo OKAY 2>&1`;
		echo ".";	
		
		if (preg_match("/OKAY/s",$out)) {
			break;
		}			
	}
	echo " ok.\n";	

	// Install the TinyProxy software. No further installation/setup needed!
	// Parse the output of 'apt-get' for 'Now installed'/...
	echo "[".date("H:i:s")."] Installing TinyProxy via SSH ... ";
	
	$out = `ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no $LOGIN@{$machine['dns']} -i "$AWS_KEYPAIR_FILE" sudo apt-get install tinyproxy 2>&1`;
	if (preg_match("/Starting tinyproxy: tinyproxy./s",$out)) {
		echo "Now installed.\n";
	}
	else if (preg_match("/tinyproxy is already the newest version./s",$out)) {
		echo "Already installed.\n";
	}
	else {
		die("Unknown output. ABORTING.\n$out\n");
	}
				
	// Open SSH tunnel in the background
	echo "[".date("H:i:s")."] Starting SSH Tunnel to Proxy at localhost:$LOCAL_PORT ... ";
	echo `ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no $LOGIN@{$machine['dns']} -i "$AWS_KEYPAIR_FILE" -L $LOCAL_PORT:localhost:$LOCAL_PORT -N >/dev/null 2>&1 &`;
	echo "started.\n";
		
	// Test proxy by locally 'wget'ing the Google website via the proxy
	echo "[".date("H:i:s")."] Testing proxy localhost:$LOCAL_PORT ...";
	while (true) {
		$out = `http_proxy=http://localhost:$LOCAL_PORT wget -O /dev/null http://www.google.com/ 2>&1`;
		echo ".";	
		
		if (!preg_match("/Connection refused/s",$out)) {
			 break;
		}			
		
		sleep(1);		
	}
	
	echo " works!\n";	
}

// OPTION 'stop'
else if ($argv[1] == "stop") {
	$instance = findInstance();
	
	// Not running
	if (!$instance) {
		exit;
	}

	// Running: Now call 'ec2-terminate-instances'
	echo "[".date("H:i:s")."] Terminating instance {$instance['instance']} ... ";
	
	$out = `ec2-terminate-instances {$instance['instance']}`;
	if (preg_match("/{$instance['instance']}	running	shutting-down/s",$out)) {
		echo "Shutting down.\n";
	}		
	else {
		echo "Unknown status.\n$out";
	}
}

// OPTION 'status'
else if ($argv[1] == "status") {
	$instance = findInstance();
}

// Invalid usage
else {
	showUsage();
}

exit;


/// HELPER FUNCTIONS ///////////////////////////////////////////////////////////

function findInstance($instance = false, $silent = false) {
	global $AMI;
	
	if ($instance) {
		if (!$silent) echo "[".date("H:i:s")."] Check for running instance $instance ...";
	}
	else {
		if (!$silent) echo "[".date("H:i:s")."] Check for running instance of $AMI ...";
		$instance = "\S+";
	}

	// Already running?
	if (preg_match("/INSTANCE	($instance)	$AMI	(\S+)	\S+	running/s",`ec2-describe-instances`,$m)) {
		$instance = $m[1];
		$dns = $m[2];	
		if (!$silent) echo " $instance running at $dns\n";	
		
		return array(
			"instance" => $instance,
			"dns" => $dns
		);
	}
	
	if (!$silent) echo " Not running.\n";	
	return false;	
}

function showUsage() {
	die("Usage: {$_SERVER['PHP_SELF']} (start|stop|status)\n");
}

?>