Semi-automated Nexus update script

update-nexus.sh

#!/bin/bash -e

cd $(dirname "$0")

log() {
	echo -e "\e[92m---\e[39m $1"
}

err() {
	echo -e "\e[91m!!!\e[39m $1" >&2
}

log "Fetching current hash"
if [ -f current.sha1 ]; then
	oldhash=$(cat current.sha1)
else
	oldhash="???"
fi
newhash=$(wget -O- https://download.sonatype.com/nexus/3/latest-unix.tar.gz.sha1)

if [ "$newhash" == "$oldhash" ]; then
	log "No new version detected"
	exit 0
fi

log "Downloading new version (old: $oldhash, new: $newhash)"
wget https://download.sonatype.com/nexus/3/latest-unix.tar.gz -O nexus-latest-unix.tar.gz

log "Checking hash"
calchash=$(sha1sum nexus-latest-unix.tar.gz | cut -d ' ' -f1)
if [ "$calchash" != "$newhash" ]; then
	err "Hash mismatch, calculated $calchash"
	exit 1
fi
log "Hash matches"

log "Getting version number"
newversion=$(tar -tf nexus-latest-unix.tar.gz | sed -nE "s/^nexus-([^/]+).*/\1/; T; p" | head -n1)
if [ -z "$newversion" ]; then
	err "Failed to detect version"
	exit 1
fi

log "New version: $newversion"

if [ -f /etc/init.d/nexus ]; then

	if service nexus status | grep -q running; then
		log "Stopping old service"
		service nexus stop
	else
		log "Service not running - nothing to do"
	fi

	rm /etc/init.d/nexus
fi

log "Extracting"
tar -xf nexus-latest-unix.tar.gz

# Find new version
newfolder="$(realpath "nexus-$newversion")"
log "New version at $newfolder"

log "Preparing system"

# Configure Java VM
sed -ri "s%^# (INSTALL4J_JAVA_HOME_OVERRIDE)=%\1=/opt/jdk8u302-b08-jre%" "$newfolder/bin/nexus"

# Create symbolic link
ln -s "$newfolder/bin/nexus" /etc/init.d/nexus

cat <<"EOF" >"$newfolder/bin/nexus.rc"
run_as_user="nexus"
EOF

echo "$calchash">current.sha1

log "Starting"
service nexus start

log "Removing really old versions"
find -maxdepth 1 -type d -name "nexus-*" | sed -nE "s/^.\/nexus-([^/]+).*/\1/; T; p" | sort -nr | tail -n +3 | while read oldver; do
	log "Removing $oldver"
	rm -r nexus-$oldver
done

log "Done. Have a good day"