Skip to content

Instantly share code, notes, and snippets.

@chetan
Forked from cobusbernard/update-route53.sh
Created June 1, 2015 19:03
Show Gist options
  • Save chetan/aac5f03c9ad6a0772ce4 to your computer and use it in GitHub Desktop.
Save chetan/aac5f03c9ad6a0772ce4 to your computer and use it in GitHub Desktop.
#!/bin/bash
# Copied from http://willwarren.com/2014/07/03/roll-dynamic-dns-service-using-amazon-route53/
# Externalizing the zone ID and CNAME
if [ -z "$1" ]
then
echo "The first argument needs to be the Hosted Zone ID, i.e. BJBK35SKMM9OE"
exit 1
fi
if [ -z "$2" ]
then
echo "The second argument needs to be CNAME to update, i.e. example.com"
exit 1
fi
if [ -z "$3" ]
then
echo "The third argument needs to be AWS IAM role that has access to this domain, i.e. your-dns-updater"
exit 1
fi
# Hosted Zone ID e.g. BJBK35SKMM9OE
ZONEID=$1
# The CNAME you want to update e.g. hello.example.com
RECORDSET=$2
# The IAM user profile to use
IAM_PROFILE=$3
# Force the update
if [ "$4" == "1" ];
then
echo "Force update is set."
FORCE_UPDATE=1
fi
# More advanced options below
# The Time-To-Live of this recordset
TTL=300
# Change this if you want
COMMENT="Auto updating @ `date`"
# Change to AAAA if using an IPv6 address
TYPE="A"
# Get the external IP address
IP=`curl -sSk https://wtfismyip.com/text`
function valid_ip()
{
local ip=$1
local stat=1
if [[ $ip =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then
OIFS=$IFS
IFS='.'
ip=($ip)
IFS=$OIFS
[[ ${ip[0]} -le 255 && ${ip[1]} -le 255 \
&& ${ip[2]} -le 255 && ${ip[3]} -le 255 ]]
stat=$?
fi
return $stat
}
# Get current dir (stolen from http://stackoverflow.com/a/246128/920350)
DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
LOGFILE="$DIR/update-route53.log"
IPFILE="$DIR/update-route53.ip"
if ! valid_ip $IP; then
echo "Invalid IP address: $IP" >> "$LOGFILE"
exit 1
fi
# Check if the IP has changed
if [ ! -f "$IPFILE" ]
then
touch "$IPFILE"
fi
if grep -Fxq "$IP" "$IPFILE"; then
# code if found
echo "IP is still $IP. Exiting" >> "$LOGFILE"
if [ -z "$FORCE_UPDATE" ]; then
echo "Exiting..."
exit 0
fi
fi
echo "IP has changed to $IP, updating ..."
echo "IP has changed to $IP" >> "$LOGFILE"
# Fill a temp file with valid JSON
TMPFILE=$(mktemp /tmp/temporary-file.XXXXXXXX)
cat > ${TMPFILE} << EOF
{
"Comment":"$COMMENT",
"Changes":[
{
"Action":"UPSERT",
"ResourceRecordSet":{
"ResourceRecords":[
{
"Value":"$IP"
}
],
"Name":"$RECORDSET",
"Type":"$TYPE",
"TTL":$TTL
}
}
]
}
EOF
# Update the Hosted Zone record
aws route53 change-resource-record-sets \
--profile $IAM_PROFILE \
--hosted-zone-id $ZONEID \
--change-batch file://"$TMPFILE" >> "$LOGFILE"
echo "" >> "$LOGFILE"
# Clean up
rm $TMPFILE
# All Done - cache the IP address for next time
echo "$IP" > "$IPFILE"
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment