pihole-gemini - Two-way Pi-hole lists sync

#! /bin/bash
# Script was last updated 03-12-2019

SCRIPTVER="pihole-gemini v0.0.2.2a"
# --------------------------------------------------------------------------------------------------------
# This script was written to try and keep the white and black lists in sync between two Pi-holes.

# The script should be launched from /opt/pihole/gravity.sh
# It should be called in the second to last line of the gravity.sh file and should be run as the user
# configured for the sync process. In my case, I'm using user pi, so you would change the user from 'pi'
# to the username you're using to sync the files (the user you're assigning to HAUSER in this script.)

# Example of the line to add as the second to last line of the /opt/pihole/gravity.sh file:

#       su -c '/usr/local/bin/pihole-gemini' - pi

# In the above example, you change the 'pi' at the end to your sync user, and it should appear directly
# above the line that reads:
#       "${PIHOLE_COMMAND}" status
# in the /opt/pihole/gravity.sh file.

# --------------------------------------------------------------------------------------------------------
# USER-DEFINED VARIABLES - START - Edit the values in this section to configure the script to your install.

    # User account - Should have sudo and ssh access, and a "matching" account should be set up on both Pi-hole systems
        HAUSER=pi

    # Pi-hole directory (this path is expected to be the same on both Pi-holes, and should be where the FILES are located)
        PIHOLEDIR=/etc/pihole

    # IP Addresses - Note that removing the value or the variable definition of either SSHPORT will cause the script to
                #    use the default SSH Port of 22 for connections to that ip address.
        # Primary Pi-hole ip and ssh port
            PIHOLE1=192.168.1.2
            SSHPORT1=22

        # Secondary Pi-hole ip and ssh port
            PIHOLE2=192.168.1.3
            SSHPORT2=22

    # Define the local path to store the logfile, DO NOT include a trailing "/". Make sure this path is writeable by the user
    # that runs the sync. Change this from /tmp to another folder to prevent logs from being cleared on system restart
        LOGFILEPATH="/tmp"

    # How long to keep old log files (in addition to the current day's log, so a value of 6 means 7 days)
        LOGKEEPDAYS=6

# USER-DEFINED VARIABLES - END - Edits made below this line may break the script.
# ---------------------------------------------------------------------------------------------------------

# SCRIPT VARIABLES - START - These values are used by the script and should not be changed manually.

    # List of files to sync
        FILES=(
            'black.list'
            'blacklist.txt'
            'regex.list'
            'whitelist.txt'
            'lan.list'
            'adlists.list'
            'gravity.list'
        )

    # Full logfile path and name, uncluding timestamp
        LOGFILE="${LOGFILEPATH}/pihole-gemini_`date +\%Y\%m\%d`.log"

    # Flags used to determine script blocks to run.
        # RUNUPDATE - 0 = Don't update; 1 = update Pi-holes
        RUNUPDATE=0

        # RESTART - 0 = Don't restart; 1 = restart
        RESTART=0

        # RUNGRAVITY - 0 = Don't update gravity; 1 = Update gravity (don't download lists)
        RUNGRAVITY=0

        # DEFAULT SSHPORT - This value is only provided here to use the default port of 22 if a port is not defined for the specified ip address
        DEFAULTSSHPORT=22

        # INITIALIZE PORT VARIABLES - This segment keeps the SSHPORT variables as set in the user-defined variables section. They are included here
                                    # mainly as a fallback in case the variables are accidentally removed from the user-defined variables section.
            SSHPORT1=$SSHPORT1
            SSHPORT2=$SSHPORT2

        # DETERMINE IP AND PORTS TO USE - START
            # This section checks the interface used to connect to the local gateway, then determines the current ip address
            # based on that interface. Finally, it checks the current ip address against the two addresses the script has
            # configured to determine which one is the remote Pi-hole to send commands to, and configures the appropriate port.

                LOCALGATEWAY=$(ip -4 route | awk '{print $3}' | head -n 1)
                LOCALINTERFACE=$(ip -4 route | awk '{print $3}' | tail -n 1)
                LOCALIP=$(ip -4 -o addr show $LOCALINTERFACE | awk '{print $4}' | cut -d "/" -f 1)
                    case $LOCALIP in
                        $PIHOLE1)
                            # echo "Local ip address matches PIHOLE1 ip, so the remote Pi-hole is PIHOLE2."
                            REMOTEPI=$PIHOLE2
                            if [ -z $SSHPORT2 ]; then
                                # SSHPORT2 value is empty, use the default ssh port.
                                SSHPORT=$DEFAULTSSHPORT
                            else
                                # SSHPORT2 value exists, use that for connections to PIHOLE2.
                                SSHPORT=$SSHPORT2
                            fi
                        ;;
                        $PIHOLE2)
                            # echo "Local ip address matches PIHOLE2 ip, so the remote Pi-hole is PIHOLE1."
                            REMOTEPI=$PIHOLE1
                            if [ -z $SSHPORT1 ]; then
                                # SSHPORT1 value is empty, use the default ssh port.
                                SSHPORT=$DEFAULTSSHPORT
                            else
                                # SSHPORT1 value exists, use that for connections to PIHOLE1.
                                SSHPORT=$SSHPORT1
                            fi
                        ;;
                        *)
                            echo "--------------------------------------------------------------------------------------------" 2>&1 | tee -a $LOGFILE
                            echo "* `date '+%Y-%m-%d %H:%M:%S'` - ERROR! - $SCRIPTVER was unable to determine the local ip address." 2>&1 | tee -a $LOGFILE
                            echo "                                  This is a fatal error. Script can not continue. Please check your" 2>&1 | tee -a $LOGFILE
                            echo "                                  configuration for the script, and make sure you are connected to" 2>&1 | tee -a $LOGFILE
                            echo "                                  your router and have an ip address assigned." 2>&1 | tee -a $LOGFILE
                            echo "--------------------------------------------------------------------------------------------" 2>&1 | tee -a $LOGFILE
                            REMOTEPI="Unknown"
                            exit 1
                        ;;
                    esac

        # DETERMINE IP AND PORTS TO USE - END

# SCRIPT VARIABLES - END

# LOG HEADER START - The following echo commands are for formatting purposes in the log file.
    echo "--------------------------------------------------------------------------------------------" 2>&1 | tee -a $LOGFILE
    echo "`date '+%Y-%m-%d %H:%M:%S'` - $SCRIPTVER was successfully launched as user: $USER" 2>&1 | tee -a $LOGFILE
    echo "                      $LOCALIP is updating Pi-hole on $REMOTEPI"
    echo "--------------------------------------------------------------------------------------------" 2>&1 | tee -a $LOGFILE
# LOG HEADER - END

# SSH CONNECTION TEST - START
    echo "`date '+%Y-%m-%d %H:%M:%S'` - Testing SSH Connection to $HAUSER@$REMOTEPI. Please wait." 2>&1 | tee -a $LOGFILE

    ssh -q -p $SSHPORT $HAUSER@$REMOTEPI exit
    SSHSTATUS=$?

        if [ $SSHSTATUS -eq 0 ]; then
            # SSH is up
            echo "`date '+%Y-%m-%d %H:%M:%S'` - SSH Connection to $HAUSER@$REMOTEPI was tested successfully." 2>&1 | tee -a $LOGFILE
            RUNUPDATE=1

        else
            # SSH is down
            echo "* `date '+%Y-%m-%d %H:%M:%S'` - ERROR! Unable to establish SSH connection as $HAUSER@$REMOTEPI on port $SSHPORT." 2>&1 | tee -a $LOGFILE
            echo "*                       This is a fatal error as SSH is required for this script. Unable to update $REMOTEPI on port $SSHPORT." 2>&1 | tee -a $LOGFILE
            echo "*                       $REMOTEPI may be offline, you may have specified the wrong port, or you have not correctly configured your SSH keys." 2>&1 | tee -a $LOGFILE
            echo "*                       $REMOTEPI has NOT been updated."
            RUNUPDATE=0
        fi
# SSH CONNECTION TEST - END

# UPDATE REMOTE PIHOLE - START
    if [ $RUNUPDATE -eq 1 ]; then
    echo "--------------------------------------------------------------------------------------------" 2>&1 | tee -a $LOGFILE

    # FILE SYNC - START - This section handles compares the local and remote versions of the files specified in the $FILES variable
                    #     and updates the remote files if neccesary.
        for FILE in ${FILES[@]}
            do
                if [[ -f $PIHOLEDIR/$FILE ]]; then
                    echo "`date '+%Y-%m-%d %H:%M:%S'` - Comparing local to remote $FILE and updating if neccesary." 2>&1 | tee -a $LOGFILE

                    RSYNC_COMMAND=$(rsync --rsync-path='/usr/bin/sudo /usr/bin/rsync' -aiu -e "ssh -l $HAUSER@$REMOTEPI -p$SSHPORT" $PIHOLEDIR/$FILE $HAUSER@$REMOTEPI:$PIHOLEDIR)

                        if [[ -n "${RSYNC_COMMAND}" ]]; then
                            # rsync copied changes so restart

                            case $FILE in
                                adlists.list)
                                    # Updating adlists.list requires only a gravity update
                                    echo "`date '+%Y-%m-%d %H:%M:%S'` - Updated $FILE on $REMOTEPI. Gravity will be updated on $REMOTEPI." 2>&1 | tee -a $LOGFILE
                                    RUNGRAVITY=1
                                ;;

                                gravity.list)
                                    # Updating gravity.list requires only a gravity update
                                    echo "`date '+%Y-%m-%d %H:%M:%S'` - Updated $FILE on $REMOTEPI. Gravity will be updated on $REMOTEPI." 2>&1 | tee -a $LOGFILE
                                    RUNGRAVITY=1
                                ;;

                                *)
                                    # Updating white and/or black lists (or other files) requires a remote restart but not a gravity update
                                    echo "`date '+%Y-%m-%d %H:%M:%S'` - Updated $FILE on $REMOTEPI. $REMOTEPI will be restarted." 2>&1 | tee -a $LOGFILE
                                    RESTART=1
                                ;;
                            esac

                        else
                            # no changes so do nothing
                            echo "`date '+%Y-%m-%d %H:%M:%S'` - Local file $FILE matches $FILE on $REMOTEPI. Remote file was not updated." 2>&1 | tee -a $LOGFILE
                        fi

                else
                    # file does not exist, skipping
                    echo "`date '+%Y-%m-%d %H:%M:%S'` - Local file $FILE does not exist. Skipping." 2>&1 | tee -a $LOGFILE
                fi
            done
    # FILE SYNC - END

    # RESTART REMOTEPI (IF NEEDED) - START
        if [ $RESTART -eq 1 ]; then
            echo "--------------------------------------------------------------------------------------------" 2>&1 | tee -a $LOGFILE
            echo "`date '+%Y-%m-%d %H:%M:%S'` - Updated files have been copied to $REMOTEPI. Restarting..." 2>&1 | tee -a $LOGFILE

            echo "`date '+%Y-%m-%d %H:%M:%S'` - Sending restart command to pihole-FTL on $REMOTEPI." 2>&1 | tee -a $LOGFILE

            ssh $HAUSER@$REMOTEPI -p $SSHPORT "sudo -S service pihole-FTL restart"
            if [ $? -ne 0 ]; then
                echo "* `date '+%Y-%m-%d %H:%M:%S'` - ERROR! - Unable to restart pihole-FTL service on $REMOTEPI." 2>&1 | tee -a $LOGFILE

            else
                echo "`date '+%Y-%m-%d %H:%M:%S'` - Successfully restarted pihole-FTL service on $REMOTEPI." 2>&1 | tee -a $LOGFILE
            fi
        fi
    # RESTART REMOTEPI - END

    # UPDATE REMOTE GRAVITY (IF NEEDED) - START
    echo "--------------------------------------------------------------------------------------------" 2>&1 | tee -a $LOGFILE
        case $RUNGRAVITY in
            0)
                # Gravity did not need updating - do nothing
                echo "`date '+%Y-%m-%d %H:%M:%S'` - Gravity on $REMOTEPI did not need updating." 2>&1 | tee -a $LOGFILE
            ;;
            1)
                # Gravity needs refreshing, but not a full update - Update gravity without redownloading lists
                echo "`date '+%Y-%m-%d %H:%M:%S'` - Refreshing gravity on $REMOTEPI. Lists will not be redownloaded." 2>&1 | tee -a $LOGFILE
                ssh $HAUSER@$REMOTEPI -p $SSHPORT "sudo -S pihole -g --skip-download"
                if [ $? -ne 0 ]; then
                    echo "* `date '+%Y-%m-%d %H:%M:%S'` - ERROR! - Unable to refresh gravity on $REMOTEPI." 2>&1 | tee -a $LOGFILE

                else
                    echo "`date '+%Y-%m-%d %H:%M:%S'` - Success! Successfully refreshed gravity on $REMOTEPI." 2>&1 | tee -a $LOGFILE
                fi
            ;;
        esac
    # UPDATE REMOTE GRAVITY - END

    # CLEAN OLD LOG FILES - START
        # Check the LOGFILEPATH for outdated log files and delete old logs
        echo "--------------------------------------------------------------------------------------------" 2>&1 | tee -a $LOGFILE
        echo "`date '+%Y-%m-%d %H:%M:%S'` - Checking ${LOGFILEPATH} for outdated log files." 2>&1 | tee -a $LOGFILE

        look_in="${LOGFILEPATH}/pihole-gemini_*.log"

        del_file=`find $look_in ! -name $LOGFILE -daystart -mtime +$LOGKEEPDAYS`
        if [ -z "$del_file" ]; then
            echo "`date '+%Y-%m-%d %H:%M:%S'` - There were no outdated log files to remove." 2>&1 | tee -a $LOGFILE

        else
            echo "`date '+%Y-%m-%d %H:%M:%S'` - Outdated log file(s) found. Removing..." 2>&1 | tee -a $LOGFILE
            sudo find $look_in ! -name $LOGFILE -daystart -mtime +$LOGKEEPDAYS -prune -exec rm -rv "{}" \;
            if [ $? -ne 0 ]; then
                echo "`date '+%Y-%m-%d %H:%M:%S'` - ERROR! Unable to remove outdated log files from $LOGFILEPATH." 2>&1 | tee -a $LOGFILE
            else
                echo "`date '+%Y-%m-%d %H:%M:%S'` - Outdated log files successfully cleaned." 2>&1 | tee -a $LOGFILE
            fi
        fi
    # CLEAN OLD LOG FILES - END

    fi
# UPDATE REMOTE PIHOLE - END

# LOG FOOTER - START
    echo "--------------------------------------------------------------------------------------------" 2>&1 | tee -a $LOGFILE
    echo "`date '+%Y-%m-%d %H:%M:%S'` - $SCRIPTVER completed update of $REMOTEPI from $LOCALIP." 2>&1 | tee -a $LOGFILE
    echo "--------------------------------------------------------------------------------------------" 2>&1 | tee -a $LOGFILE
# LOG FOOTER - END

# END OF SCRIPT