ec2-hosts.sh

#!/bin/bash
set -e

usage() {
	echo "Usage: $(basename $0) [ -i|--internal ] [ -s|--skip-cached ] [ --name NAME | --prefix PREFIX ] [-- options]"
	echo "  -i | --internal        use internal IPs instead of external"
	echo "  -e | --external        use external IPs instead of internal (default)"
	echo "  -s | --skip-cached     skip the cached result of ec2-describe-instances, it gets cached for max 1 hour"
	echo "  --name NAME            filter the output by instance NAME"
	echo "  --prefix PREFIX        filter the output by instance name PREFIX"
	echo "  options                passed to 'ec2-describe-instances'"
	echo ""
	echo "Examples: "
	echo "   $(basename $0) --name db16"
	echo "   $(basename $0) --prefix web"
	echo "   $(basename $0) -i -- --filter group-name=db"
	echo ""	
}

require_var() {
	for name in $*; do
		var=${!name}
		[ -z "$var" ] && fatal "Missing environment variable \"$name\"" || true
	done
}

require_bin() {
	for binary in $*; do
		which $binary >/dev/null \
		|| fatal "Command \"$binary\" not found." \
				 "Did you run 'make' from $BASEDIR ?"
	done
}

fatal() {
	echo "ERROR: $1" >&2
	shift
	while [ ! -z "$1" ]; do
		echo "       $1" >&2
		shift
	done
	echo -e "\nexiting." >&2
	exit 1
}

error() {
	echo "ERROR: $1" >&2
	shift
	while [ ! -z "$1" ]; do
		echo "       $1" >&2
		shift
	done
}

logn() {
	echo -n [$(date +'%Y-%m-%d %H:%M:%S')] $*
}

log() {
	echo [$(date +'%Y-%m-%d %H:%M:%S')] $*
}

timer() {
	if [[ $# -eq 0 ]]; then
		echo $(date '+%s')
	else
		local  stime=$1
		etime=$(date '+%s')
		if [[ -z "$stime" ]]; then stime=$etime; fi
		dt=$((etime - stime))
		ds=$((dt % 60))
		dm=$(((dt / 60) % 60))
		dh=$((dt / 3600))
		if [[ $dh -gt 0 ]]; then
			printf '%d hours %2d min' $dh $dm $ds
		elif [[ $dm -gt 0 ]]; then
			printf '%2d min %2d sec' $dm $ds
		else
			printf '%2d sec' $ds
		fi
	fi
}


require_var "EC2_PRIVATE_KEY" "EC2_CERT" \
			"EC2_HOME" "EC2_REGION" "EC2_ZONE"
require_bin "ec2-describe-instances"

INTERNAL="NO"
CACHED=""
PASS_OPTS=
FILTER_NAME=""
FILTER_PREFIX=""
until [ -z "$1" ]; do
  case $1 in
    -i|--internal)
            shift; INTERNAL="YEA"; 
            ;;
    -e|--external)
            shift; INTERNAL="NO"; 
            ;;
    -c|--cached)
            shift; CACHED="YEA";
            ;;
    -s|--skip-cached)
            shift; CACHED="NO";
            ;;
    --name)
            shift; FILTER_NAME="$1"; shift
            ;;
    --prefix)
            shift; FILTER_PREFIX="$1"; shift
            ;;
    --)
            shift; PASS_OPTS=$*
            break;
            ;;
    -h|--help)
            usage;
            exit 0
            ;;
    *)
            echo "unknown option: $1";
            usage;
            exit 1
            ;;
  esac
done

if [ -z "$CACHED" ]; then
	if [ ! -z "$PASS_OPTS" ]; then
		CACHED="NO"
	else
		CACHED="YEA"
	fi
fi

if [ "$CACHED" = "YEA" -a ! -z "$PASS_OPTS" ]; then
	echo "invalid argument: can not use opt -c|--cached when passing special params to ec2-describe-instances"
	exit 1;
fi

CACHEFILE="/tmp/.ec2-hosts-cache"
if [ "$CACHED" = "YEA" ]; then
	if [ ! -e $CACHEFILE -o ! "$(find $CACHEFILE -mmin +60 2>/dev/null)" = "" ]; then
		OUTPUT=$(ec2-describe-instances | tee $CACHEFILE)
	else
		OUTPUT=$(cat $CACHEFILE)
	fi
elif [ -z "$PASS_OPTS" ]; then
	OUTPUT=$(ec2-describe-instances | tee $CACHEFILE)
else
	OUTPUT=$(ec2-describe-instances $PASS_OPTS)
fi

#OUTPUT=$(cat dogbarf)
NAMES=$(echo "$OUTPUT" | grep ^TAG | grep Name | awk '{print $3" "$5}')
HOSTS=$(echo "$OUTPUT" | grep ^INSTANCE | grep running | awk 'BEGIN{FS="\t"};{print $2"\t"$18"\t"$5"\t"$17"\t"$4}')

(
IFS=$'\t'
echo "$HOSTS" | while read line; do 
	set -- $line
	ID="$1"
	PRIVATE_IP="$2"
	PRIVATE_HOST="$3"
	PUBLIC_IP="$4"
	PUBLIC_HOST="$5"
	NAME=$(echo "$NAMES" | grep ^$ID | awk '{print $2}')
	IP=$(test "$INTERNAL" = "YEA" && echo "$PRIVATE_IP" || echo "$PUBLIC_IP")
	SHOW="YEA"
	if [ ! -z "$FILTER_NAME" ]; then
		[ "$FILTER_NAME" = "$NAME" ] || SHOW="NO"
	elif [ ! -z "$FILTER_PREFIX" ]; then
		[ "$FILTER_PREFIX" = "${NAME:0:${#FILTER_PREFIX}}" ] || SHOW="NO"
	fi
	[ "$SHOW" = "YEA" ] && printf '%-16s %s %-16s % 52s % 45s\n' "$IP" "$ID" "$NAME" "$PUBLIC_HOST" "$PRIVATE_HOST"
done
) | sort -k 3 # sorting by name