gitea auto update cron.txt

## NOTE! this works for me but has recieved very limited testing!

## Enable auto updates for GITEA:
# shell script to check github repo for "latest" tag and compare to current running gitea version
#   assumes systemd is in use to manage gitea service
#   assumes gitea binary file lives at: /usr/local/bin/gitea
#   assumes Ubuntu 18.04 is in use (but should work on any debian / apt system)
#   assumes your local gitea api instance is reachable at: "http://192.168.4.22:3000/api/v1/version"
#   assumes your ok with downloading the latest binary from github without any validation
#

# install jq json query parser:
sudo apt install jq

# create a new script file:
sudo nano /opt/gitea-auto-upgrade.sh

# Put the following script into that file:
#!/usr/bin/env bash
upstreamdata=$(curl -s "https://api.github.com/repos/go-gitea/gitea/releases/latest")

upstreamver=$(echo $upstreamdata | jq -r ".tag_name")

curver=$(gitea -v|awk '{print $3}')

# use bash replacement to get rid of the "v" from the github tag to allow DIFF to work correctly:
changed=$(diff <(echo "$curver") <(echo "${upstreamver//v}"))

# check if diff output a null value or not. the statement reads: "if $changed is not null then"
if [ "$changed" != "" ]
then

        echo "Installed Gitea version does not match upstream latest, beginning upgrade procedure:"

        ### UPGRADE ###
        systemctl stop gitea

        # get the current binary out of the production location:
        sudo mv -f /usr/local/bin/gitea /usr/local/bin/gitea.previous

        # get url for new version from the JSON data pulled from github:
        newverurldata=$(echo $upstreamdata | jq -r '.assets[]  | select(.name | contains("linux-amd64")).browser_download_url')

        newverurl=$(echo $newverurldata |awk '{print $1}')

        # download the new version
        cd /tmp
        wget -O gitea $newverurl
        chmod +x gitea

        #move the downloaded updated gitea binary to the production location:
        mv gitea /usr/local/bin/gitea

        # start the service:
        systemctl start gitea
        ### UPGRADE DONE ###

        echo "Gitea upgrade procedure finished"

else
        echo "Installed Gitea version matches upstream latest version, no action taken"
fi

######### end script contents ##########

# set it to be executable:
sudo chmod +x /opt/gitea-auto-upgrade.sh

# run it manually once to make sure it is executable and returns correct output:
sudo /opt/gitea-auto-upgrade.sh

# open up the root crontab file:
sudo crontab -e

# add this line to the cron file, this runs the script everyday at 3am, and puts all output into the syslog
0 3 * * * /opt/gitea-auto-upgrade.sh 2>&1 | logger -t gitea-auto-upgrade