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

Public DNS, Elastic IP 情報をキャッシュファイルに保存しておいて、次回のアクセス時は ec2-api-tools による AWS への問い合わせをせずにすぐに EC2 にアクセスするようにしてみました。アクセスに失敗した場合は問い合わせし直してキャッシュを更新します。動作確認してるのは今のところ Mac OS 10.8.3 のみ。あとは個人的趣味なメッセージ出力系の変更。以下、変更内容詳細。

• 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)
• 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

CentOS 6.4 でも動作することを確認しています。