post-receive hook for synchronizing BIND masters

post-receive

#!/bin/bash

unset GIT_DIR

REPO_DIR=/var/lib/gitosis/repositories/internal_dns.git
CLONE_DIR=/var/named/chroot/var/named/data
ERR_OUT=/tmp/named_error.out.$$

if [ ! -e "${CLONE_DIR}/.git" ]; then
  git clone "$REPO_DIR" "$CLONE_DIR"
fi

cd "$CLONE_DIR"

git fetch
git checkout master
git reset --hard origin/master

# Syntax check
sudo /usr/sbin/named-checkconf -t /var/named/chroot -z &> $ERR_OUT
if [ $? != 0 ]; then
  echo "*******************"
  echo "SYNTAX CHECK FAILED"
  echo "*******************"
  echo -e "DNS config syntax check failed:\n\n$(<$ERR_OUT)" | mail -s "DNS config syntax check failed" -c notifications@example.org
  exit 1
fi
rm $ERR_OUT 2>/dev/null

# Since this is the master and nothing is querying us, it's "cleaner" and easier to just restart vs. reload.
# This also handles the case of a first deployment where named is not yet running.
sudo /sbin/service named stop

# Make sure it's really stopped
count=0
while /bin/true; do
  count=$(($count + 1))
	if [ $count -ge 10 ]; then
		echo "Not waiting anymore for named to shut down"
		exit 1
	fi
	if [ -n "$(pgrep named)" ]; then
		echo "The 'named' process is still running"
		sleep 1s
	else
		echo "The 'named' process has stopped"
		break
	fi
done

# Start it back up
sudo /sbin/service named start

# Push updates to other masters
MASTERS="master1.example.org master2.example.org master3.example.org"

# This will technically trigger an endless loop of pushes and repushes, but the fact that the post-receive hook isn't run if no new objects are pushed "saves" us
for MASTER in $MASTERS; do
  if [ "$(hostname)" = $MASTER ]; then
    # We don't need to push to ourselves
    continue
  fi
  git push --mirror ssh://gitosis@${MASTER}/internal_dns.git
done