#!/bin/bash
#
#  ozec2:  spawn Mozart/Oz remote computations on a fresh EC2 instance
#
#  Copyright 2009, Ryan Kelly.
#  Redistributable under the terms of the BSD license.
#  http://www.opensource.org/licenses/bsd-license.php
#
#  This script acts as a Mozart/Oz fork command, spawning a new machine
#  instance on Amazon EC2, installing Mozart, and then executing the
#  given command on the instance using ssh.  It expects to be called as
#  follows:
#
#    ozec2 <hostname> <command> <args>
#
#  Since a fresh machine instance will be created, the hostname argument
#  is simply ignored.
#
#  To use, simply tweak the configuration below (or set the appropriate
#  environment variables) and place it somewhere in your PATH.  Then you
#  can do fun things like launching a remote computation on EC2:
#
#    {New Remote.manager init(fork:ozec2)}
#
#  Or spinning up some EC2 instances to run a paralel search:
#
#    {New Search.parallel init(unit:6#ozec2)}
#
#  This assumes that you have a working installation of the Amazon EC2
#  command-line utilities, including the necessary environment variables.
#


###   Configuration Variables


# Whether to print debugging info
if [ "x$OZEC2_DEBUG" = "x" ]
then
    OZEC2_DEBUG=""
fi

#  The machine image to use.  By default it's a public ubuntu image.
if [ "x$OZEC2_AMI" = "x" ]
then
    OZEC2_AMI="ami-1a5db973"
fi

#  Any additional args for launching the instance
if [ "x$OZEC2_INSTANCE_ARGS" = "x" ]
then
    OZEC2_INSTANCE_ARGS=""
fi

#  The EC2 keypair to use.  This must be registered with EC2 using the
#  specified name, and exist as a local file so SSH can use it.
if [ "x$OZEC2_KEYPAIR_FILE" = "x" ]
then
    OZEC2_KEYPAIR_FILE="$HOME/.ec2/keypair.pem"
fi
if [ "x$OZEC2_KEYPAIR_NAME" = "x" ]
then
    OZEC2_KEYPAIR_NAME="ec2-keypair"
fi

#  The Mozart/Oz tarball to download and install on the created instance.
#  Set this to "none" if the machine image already has mozart installed.
if [ "x$OZEC2_TARBALL" = "x" ]
then
    OZEC2_TARBALL="http://www.mozart-oz.org/download/mozart-ftp/store/1.3.2-2006-06-15-tar/mozart-1.3.2.20060615-linux-i486.tar.gz"
fi


###   End of configuration variables


# Ignore the first argument, it's the hostname from Mozart and isn't used
shift 1

# Launch the EC2 instance
INSTANCE=`ec2-run-instances $OZEC2_AMI -k $OZEC2_KEYPAIR_NAME $OZEC2_INSTANCE_ARGS | grep INSTANCE | cut -f 2`

if [ "x$OZEC2_DEBUG" != "x" ]
then
    echo "Launched instance, waiting for it to start"
fi

# Ensure that it gets stopped properly on exit
trap 'ec2-terminate-instances $INSTANCE > /dev/null 2>&1; exit 0' INT TERM EXIT

# Wait for it to be up and running
STATUS=pending
while [ x$STATUS != "xrunning" ]
do
  STATUS=`ec2-describe-instances | grep INSTANCE | grep $INSTANCE | cut -f 6`
done

HOSTNAME=`ec2-describe-instances | grep INSTANCE | grep $INSTANCE | cut -f 4`
SSH="ssh -q -o StrictHostKeyChecking=no -i $OZEC2_KEYPAIR_FILE root@$HOSTNAME"

if [ "x$OZEC2_DEBUG" != "x" ]
then
    echo "Instance running, hostname is $HOSTNAME"
fi

#  Poll the ssh connection, waiting for it to come up
$SSH true > /dev/null 2>&1
STATUS=$?
while [ $STATUS -ne 0 ]
do
  $SSH true > /dev/null 2>&1
  STATUS=$?
done

if [ "x$OZEC2_DEBUG" != "x" ]
then
    echo "SSH ready"
fi

#  Install Mozart
if [ "x$OZEC2_TARBALL" != "xnone" ]
then
    $SSH "wget $OZEC2_TARBALL && tar -xzvf `basename $OZEC2_TARBALL`" > /dev/null 2>&1
    $SSH "mv mozart/bin/* /usr/local/bin/ && mv mozart/include/* /usr/local/include/ && mv mozart/share/*.* /usr/local/share/ && mv mozart/platform /usr/local/platform && mv mozart/cache /usr/local/cache" > /dev/null 2>&1
    if [ "x$OZEC2_DEBUG" != "x" ]
    then
        echo "Mozart installed"
    fi
fi

#  Run the given command
if [ "x$OZEC2_DEBUG" != "x" ]
then
    echo "Running command..."
fi
$SSH $@
if [ "x$OZEC2_DEBUG" != "x" ]
then
    echo "Done"
fi