How do you parse the SRV record's port from a dig result?

Question

I'm parsing the output of dig like this to get the port of an SRV record.

export SERVER_DNS_NAME=myserver
echo "SERVER_DNS_NAME: " $SERVER_DNS_NAME
echo "dig: " $(dig +noall +answer $SERVER_DNS_NAME SRV )
echo "port old: " $(dig +noall +answer $SERVER_DNS_NAME SRV | cut -d ' ' -f 6)
SERVER_DIG_RESULT=$(dig +noall +answer $SERVER_DNS_NAME SRV )
echo "SERVER_DIG_RESULT: " $SERVER_DIG_RESULT
SERVER_STRING_ARRAY=($SERVER_DIG_RESULT)
for i in "${SERVER_STRING_ARRAY[@]}"
do
  :
  echo $i
done
SERVER_PORT=${SERVER_STRING_ARRAY[6]}
echo "server port new: " $SERVER_PORT
if [ -z $SERVER_PORT ]; then
  echo "invalid port"
  exit 1
fi
until nc -z $SERVER_DNS_NAME $SERVER_PORT
... do something

My problem is that sometimes the port is at array item 6, sometimes 7.

My question is: How do you reliably parse the port from a dig result?

Answer 1

Use the +short option to dig which will give you the most abbreviated output which is then trivially parsed:

% dig +short _xmpp-client._tcp.jabber.org. SRV
31 30 5222 hermes2v6.jabber.org.
30 30 5222 hermes2.jabber.org.

Answer 2

You may like this one too:

host -t SRV mySRVdomain.local                                           
# mySRVdomain.local has SRV record 1 1 2368 e04dc24b-96c6-4b52-8356-42be0d34e7bb.mySRVdomain.local.


# get it as host:port
host -t SRV mySRVdomain.local | sed -r 's/.+ ([^ ]+) ([^ ]+)\.$/\2:\1/g'

# This will print: e04dc24b-96c6-4b52-8356-42be0d34e7bb.mySRVdomain.local:2368
# which is the first real URL with PORT

It maybe not exactly the same that you need, but you can get the idea