Add --quiet command line option to suppress printing metadata keys

This lets us extract individual fields from IMDS in a raw form that
can be consumed directly by callers without requiring them to strip
off the keys themselves.

ec2-metadata

@@ -44,6 +44,7 @@ Options:
 
 METADATA_BASEURL="http://169.254.169.254"
 METADATA_TOKEN_PATH="latest/api/token"
+QUIET=""
 
 function set_imds_token()
 {
@@ -67,7 +68,7 @@ function get_meta()
 #print standard metric
 function print_normal_metric() {
  metric_path=$2
- echo -n $1": "
+ [ -z "$QUIET" ] && echo -n $1": "
  RESPONSE=$(get_meta ${metric_path})
  if [ -n "${RESPONSE}" ]; then
  echo "$RESPONSE"
@@ -79,11 +80,12 @@ function print_normal_metric() {
 #print block-device-mapping
 function print_block-device-mapping()
 {
- echo 'block-device-mapping: '
+ [ -z "$QUIET" ] && echo 'block-device-mapping: '
  x=$(get_meta meta-data/block-device-mapping/)
  if [ -n "${x}" ]; then
  for i in $x; do
- echo -e '\t' $i: "$(get_meta meta-data/block-device-mapping/$i)"
+ [ -z "$QUIET" ] && echo -ne '\t' "$i: "
+ echo "$(get_meta meta-data/block-device-mapping/$i)"
  done
  else
  echo not available
@@ -93,17 +95,17 @@ function print_block-device-mapping()
 #print public-keys
 function print_public-keys()
 {
- echo 'public-keys: '
+ [ -z "$QUIET" ] && echo 'public-keys: '
  x=$(get_meta meta-data/public-keys/)
  if [ -n "${x}" ]; then
  for i in $x; do
  index=$(echo $i|cut -d = -f 1)
  keyname=$(echo $i|cut -d = -f 2)
- echo keyname:$keyname
- echo index:$index
+ [ -z "$QUIET" ] && echo keyname:$keyname
+ [ -z "$QUIET" ] && echo index:$index
  format=$(get_meta meta-data/public-keys/$index/)
- echo format:$format
- echo 'key:(begins from next line)'
+ [ -z "$QUIET" ] && echo format:$format
+ [ -z "$QUIET" ] && echo 'key:(begins from next line)'
  echo "$(get_meta meta-data/public-keys/$index/$format)"
  done
  else
@@ -114,11 +116,12 @@ function print_public-keys()
 #print tags
 function print_tags()
 {
- echo 'tags: '
+ [ -z "$QUIET" ] && echo 'tags: '
  x=$(get_meta meta-data/tags/instance/)
  if [ -n "${x}" ]; then
  for i in $x; do
- echo -e '\t' $i: "$(get_meta meta-data/tags/instance/$i)"
+ echo -n -e '\t' "$i: "
+ echo "$(get_meta meta-data/tags/instance/$i)"
  done
  else
  echo not available
@@ -163,7 +166,7 @@ shortopts=almnbithokzPcpvuresdg
 longopts=(ami-id ami-launch-index ami-manifest-path ancestor-ami-ids block-device-mapping
  instance-id instance-type local-hostname local-ipv4 kernel-id availability-zone
  partition product-codes public-hostname public-ipv4 public-keys ramdisk-id
- reservation-id security-groups user-data tags help all)
+ reservation-id security-groups user-data tags help all quiet)
 
 oldIFS="$IFS"
 IFS=,
@@ -183,6 +186,9 @@ while true; do
  print_help ; shift
  exit 0
  ;;
+ --quiet)
+ QUIET=1 ; shift
+ ;;
  --)
  shift ; break
  ;;