ec2-ssh

#!/bin/sh

## EC2 automation login tool
#
# Original: http://m.igrs.jp/blog/2013/03/14/ec2-ssh/
#           https://gist.github.com/migrs/5157665
#           https://gist.github.com/MichinobuMaeda/5545875
#
# Changed by mo-ya (2013-07-06)
#
# - SSH Timeout value can be set by $EC2_SSH_TIMEOUT
# - Default mode is changed to quit. Verbose on/off is switched by $EC2_SSH_VERBOSE
# - If a cache file is not found, the file is created automatically
# - Valid duration of Cache is controlled by $EC2_SSH_CACHE_DAY (default: 1 day)
#
# Changed by mo-ya (2013-06-15)
#
# - Use Cache file
#     - Public DNS, Elastic IP Information is stored in a cache file.
#       The next access is performed without ec2-api-tools query.
#       If the access is failed, Public DNS and Elastic IP are queried by ec2-api-tools, 
#       and caches are updated.
# - If $1 is undefined, help messages and cache contents are output
# - Verbose Mode is added (controlled by $ec2_ssh_verbose)
#
# Changed by mo-ya (2013-05-20)
#
# - Default user can be set as $EC2_SSH_DEFAULT_USER
# - Default ssh key path can be set as $EC2_SSH_KEY_PATH
# - Some verbose messages are output to STDERR
#

## Settings
set -e

ssh="ssh"
ssh_timeout="2"
ec2din="ec2-describe-instances"
ec2_ssh_host_cache_set="${HOME}/.ec2-ssh.hostcache"
verbose=
cache_day=1

## Post Settings
if [ -n "$EC2_SSH_TIMEOUT" ]; then
  ssh_timeout="${EC2_SSH_TIMEOUT}"
fi
ec2_ssh_opt="-o ConnectTimeout=${ssh_timeout}"

if [ -n "$EC2_SSH_KEY_PATH" ]; then
  ec2_ssh_opt="${ec2_ssh_opt} -i ${EC2_SSH_KEY_PATH}"
fi

if [ -n "$EC2_SSH_DEFAULT_USER" ]; then
  ec2_ssh_user="${EC2_SSH_DEFAULT_USER}@"
fi

if [ -n "$EC2_SSH_CACHE_DAY" ]; then
  cache_day="${EC2_SSH_CACHE_DAY}"
fi

if [ -n "$EC2_SSH_VERBOSE" ]; then
  verbose="${EC2_SSH_VERBOSE}"
fi



## Functions
vmsg(){
  if [ -n "${verbose}" ]; then
    echo "$*" >&2
  fi
}

msg(){
  echo "$*" >&2
}

## Output Help Messages (If any arguments are not found)
if [ $# -lt 1 ]; then
  cat <<END_OF_HELP
# [ec2-ssh] Usages

  Basic Usage
    $ ec2-ssh web1
    $ ec2-ssh jonny@web1

  Access Same Name Instances (#1, #2 ...)
    $ ec2-ssh web#3

  Port Fowarding
    $ ec2-ssh -L 8080:127.0.0.1:80 web1

  Command direct execution
    $ ec2-ssh web1 ls -la
    $ ec2-ssh web1 tail -f /var/log/nginx/access.log
    $ ec2-ssh web1 vmstat 1
    $ ec2-ssh web1 -t top
    $ ec2-ssh web1 -t sudo service nginx restart

END_OF_HELP

  if [ -f "${ec2_ssh_host_cache_set}" ]; then
    cat <<END_OF_CACHE
# [ec2-ssh] Cache Lists (in "${ec2_ssh_host_cache_set}")
END_OF_CACHE

    cat ${ec2_ssh_host_cache_set}
  fi

  exit 1
fi

## Display ENVs

if [ -n "$EC2_SSH_HOST_CACHE" ]; then
  ec2_ssh_host_cache_set="$EC2_SSH_HOST_CACHE"
fi

vmsg "[ENV]"
vmsg "  EC2_SSH_KEY_PATH     = $EC2_SSH_KEY_PATH"
vmsg "  EC2_SSH_DEFAULT_USER = $EC2_SSH_DEFAULT_USER"
vmsg "  EC2_SSH_HOST_CACHE   = $ec2_ssh_host_cache_set"
vmsg "  EC2_SSH_TIMEOUT      = $ssh_timeout"
vmsg "  EC2_SSH_CACHE_DAY    = $cache_day"
vmsg "  EC2_SSH_VERBOSE      = $verbose"

## Parse Command line options (host name & number informations)

while [ $# -gt 0 ]; do
  case $1 in
    -*)
      if [ -z "$2" ]; then
        break
      elif [ "${2:0:1}" == "-" ]; then
        args="$args $1"
        shift
      else
        args="$args $1 $2"
        shift 2
      fi
      ;;
    *)
      if [ -n "$1" -a -z "$name" ]; then
        name=$1
        shift
      fi
      break
  esac
done

if [ "$name" != "${name%\#*}" ]; then
  num=${name#*\#}
  name=${name%\#*}
fi

[ -z "$num" ] && num=1

if [ "$name" != "${name%@*}" ]; then
  user=${name%@*}
  name=${name#*@}
fi

## Load EC2 Information from Local Cache
cache_hit=
msg "[Load EC2 Information from Local Cache] ... "
if [ -f "${ec2_ssh_host_cache_set}" ]; then
  host=`grep "^${name}#${num}" ${ec2_ssh_host_cache_set} | cut -f2`
  reg_date=`grep "^${name}#${num}" ${ec2_ssh_host_cache_set} | cut -f3`

  set +e
  # for GNU date
  valid_date=`date --date "${cache_day} day ago" "+%Y%m%d%H%M%S" 2>/dev/null`
  if [ -z "${valid_date}" ]; then
      # for BSD date
      valid_date=`date -v-${cache_day}d "+%Y%m%d%H%M%S" 2>/dev/null`
  fi
  set -e

  if [ -n "$host" ]; then
    cache_old=
    if [ -n "${reg_date}" ] && [ -n "${valid_date}" ];then
      if [ "${reg_date}" -lt "${valid_date}" ];then
          cache_old=1
      fi
    else
      vmsg "  WARNING: reg_date or valid_date is not found"
      vmsg "           reg_date   = $reg_date"
      vmsg "           valid_date = $valid_date"
    fi

    if [ -z "${cache_old}" ]; then
      cache_hit=1
      msg "  Cache HIT: $name => $host"
    else
      msg "  Cache OLD: older than ${cache_day} day [${reg_date}]: $name => $host"
      host=
    fi
  else
    msg "  Cache NOT FOUND: host is not found in Caches"
  fi
else
  msg "  Cache file is not found."
fi

yet_connect=1
while [ -n "${yet_connect}" ]; do
## Get EC2 Information from AWS
  if [ -z "$host" ]; then
    msg "[Get EC2 Information from AWS] ... (wait a minutes)"

    q="-F \"tag:Name=$name\""
    host=`$ec2din $q --hide-tags | grep ^INSTANCE | cut -f4 | paste -s - | cut -f$num`

    if [ -n "$host" ]; then
       vmsg "[Target] $host"
    else
      msg "ec2-ssh: Could not find ec2 instance $name [$num]"
      exit 1
    fi
  fi

## Save host information to cache
  if [ -z "$cache_hit" ] ; then
    if [ ! -f "${ec2_ssh_host_cache_set}" ]; then
      touch ${ec2_ssh_host_cache_set}
    fi
    vmsg "[Save EC2 Information to Local Cache] ... "
    cat ${ec2_ssh_host_cache_set} | grep -v "^${name}#${num}" > ${ec2_ssh_host_cache_set}.$$ | true
    cat ${ec2_ssh_host_cache_set}.$$ > ${ec2_ssh_host_cache_set}
    rm ${ec2_ssh_host_cache_set}.$$
    reg_date=`date "+%Y%m%d%H%M%S"`
    echo "${name}#${num}	${host}	${reg_date}" >> ${ec2_ssh_host_cache_set}
    vmsg "  Cache is updated."
  fi

## Access the server
  if [ -n "$user" ]; then
    ssh_user_set="${user}@"
  else
    ssh_user_set="${ec2_ssh_user}"
  fi

  msg "[Connecting EC2] ..."
  vmsg $ssh $ec2_ssh_opt $args ${ssh_user_set}$host $@
  set +e
  $ssh $ec2_ssh_opt $args ${ssh_user_set}$host $@
  ssh_stat=$?
  set -e

  if [ "$ssh_stat" = 0 ]; then
    yet_connect=
  else
    if [ -z "$cache_hit" ]; then
      msg "ERROR: Cannot Connect to [Name=$name, PublicDNS=$host]"
      msg "       Please Check Server Settings."
      exit 1
    else
      msg "WARNING: Cache Info may be obsoleted. Cache is ignored."
      host=
      cache_hit=
    fi
  fi
done