gcloud-dns-set.sh

#!/usr/bin/env bash
set -eu

[ -z "$4" ] && echo "Usage: $0 <gc-project> <zone-name> <domain-name> <value>" && exit 1

TYPE=A
PROJECT=$1
ZONE=$2
TARGET=$3
IP=$4

RS="gcloud --project=$PROJECT dns record-sets"
EXISTING=`$RS list --zone="$ZONE" | grep "$TARGET" | grep " $TYPE " | awk '{print $4}'`
echo using zone $PROJECT/$ZONE to set $TARGET type $TYPE to $IP

TX="$RS transaction"
$TX start -z=$ZONE

echo removing $EXISTING...
$TX remove -z=$ZONE \
    --name="$TARGET" \
    --type=$TYPE \
    --ttl=30 "$EXISTING" || ($TX abort -z=$ZONE && exit 1)

echo setting $TARGET=$IP...
$TX add -z=$ZONE \
   --name="$TARGET" \
   --type=$TYPE \
   --ttl=30 "$IP" || ($TX abort -z=$ZONE && exit 1)

echo committing...
TXID=$($TX execute -z=$ZONE --format json | jq -r '.id')
status=pending
while [ ! "$status" == "done" ]; do
    echo waiting for gcdns to update;
    status=$($RS changes describe $TXID -z syn-im --format json | jq -r '.status')
done
echo All done!