A script built off of @alexbosworth's backup script that monitors lnd's `channel.backup` file for changes and uploads those changes to Dropbox when detected.

lnd-channel-backup.md

Lnd Automated Channel Backup Guide

This script was inspired by @alexbosworth's channel.backup backup script and my own .lnd folder backup script. It monitors lnd's channel.backup file for changes and uploads those changes to Dropbox when detected.

Setup Script

To get started, download the script:

$ cd && wget -qN https://gist.githubusercontent.com/vindard/e0cd3d41bb403a823f3b5002488e3f90/raw/4bcf3c0163f77443a6f7c00caae0750b1fa0d63d/lnd-channel-backup.sh
$ sudo chmod +x lnd-channel-backup.sh

Setup Dropbox API Key

In your web browser, do the following:

1. Go to https://www.dropbox.com/developers/apps/create and sign in

2. Choose Dropbox Api

   

3. Choose App Folder

   

4. Name your app and click Create App to proceed

   

5. On the settings page for your new app, scroll down to OAuth 2 and click Generate

   

6. You will now see a string of letters and numbers appear. This is your Api Token. Copy this token and keep it safe for the next steps. This api token will be referenced as <dropbox-api-token> in the next step.

7. Return to your terminal and run the following to insert the api token into the backup script:

   $ TOKEN=<dropbox-api-token>
   $ cd && sed -i "s/DROPBOX_APITOKEN=\".*\"/DROPBOX_APITOKEN=\"$TOKEN\"/" lnd-channel-backup.sh
   $ unset TOKEN
   

Setup script as systemd service

Create file: sudo nano /etc/systemd/system/backup-channels.service

Note: be sure to change the <user-here> value to your own home folder's name

[Service]
ExecStart=/home/<user-here>/lnd-channel-backup.sh
Restart=always
RestartSec=1
StandardOutput=syslog
StandardError=syslog
SyslogIdentifier=backup-channels
User=root
Group=root

[Install]
WantedBy=multi-user.target

Start

sudo systemctl start backup-channels

Monitor

journalctl -fu backup-channels

Run at boot

sudo systemctl enable backup-channels

lnd-channel-backup.sh

#!/bin/bash

# SET DROPBOX API KEY FOR UPLOADS
DROPBOX_APITOKEN=""

# OPTIONAL SET A DEVICE NAME TO BE USED FOR BACKUPS (DEFAULTS TO /etc/hostname)
DEVICE=""

# INOTIFY CHECK
# --------------

install_inotify () {
	sudo apt update
	sudo apt install -y inotify-tools
}

inotifycheck () {
	dpkg -s "inotify-tools" &> /dev/null
	if [ ! $? -eq 0 ]; then
	    install_inotify
	fi
}



# SETUP
# --------------

setup_files_and_folders () {
	# Fetches the user whose home folder the directories will be stored under
	ADMINUSER=( $(ls /home | grep -v bitcoin) )

	if [ -z "$DEVICE" ] ; then
		DEVICE=$(echo $(cat /etc/hostname))
	fi
	DEVICE=$(echo $DEVICE | awk '{print tolower($0)}' | sed -e 's/ /-/g')

	# Setup folders and filenames
	DATADIR=/home/bitcoin/.lnd
	WORKINGDIR=/home/$ADMINUSER/lnd-data-backups
	BACKUPFOLDER=.lndbackup-$DEVICE

	# channel.backup file details
	CHANFILEDIR=data/chain/bitcoin/mainnet
	BACKUPFILE=channel.backup
	SOURCEFILE=$DATADIR/$CHANFILEDIR/$BACKUPFILE

	# Make sure necessary folders exist
	if [[ ! -e ${WORKINGDIR} ]]; then
	        mkdir -p ${WORKINGDIR}
	fi
	cd ${WORKINGDIR}

	if [[ ! -e ${BACKUPFOLDER} ]]; then
	        mkdir -p ${BACKUPFOLDER}
	fi
	cd ${BACKUPFOLDER}
}


# CHECKS
# --------------

online_check () {
	wget -q --tries=10 --timeout=20 --spider http://google.com
	if [[ $? -eq 0 ]]; then
	        ONLINE=true
	else
	        ONLINE=false
	fi
	#echo "Online: "$ONLINE
}

dropbox_api_check () {
	VALID_DROPBOX_APITOKEN=false
	curl -s -X POST https://api.dropboxapi.com/2/users/get_current_account \
	    --header "Authorization: Bearer "$DROPBOX_APITOKEN | grep rror
	if [[ ! $? -eq 0 ]] ; then
	        VALID_DROPBOX_APITOKEN=true
	else
		echo "Invalid Dropbox API Token!"
	fi
}

dropbox_upload_check () {
	UPLOAD_TO_DROPBOX=false
	if [ ! -z $DROPBOX_APITOKEN ] ; then
		online_check
		if [ $ONLINE = true ] ; then
			dropbox_api_check
		else
			echo "Please check that the internet is connected and try again."
		fi

		if [ $VALID_DROPBOX_APITOKEN = true ] ; then
			UPLOAD_TO_DROPBOX=true
		fi
	fi
}


# UPLOAD
# --------------

upload_to_dropbox () {
	FINISH=$(curl -s -X POST https://content.dropboxapi.com/2/files/upload \
	    --header "Authorization: Bearer "${DROPBOX_APITOKEN}"" \
	    --header "Dropbox-API-Arg: {\"path\": \"/"$BACKUPFOLDER"/"$1"\",\"mode\": \"overwrite\",\"autorename\": true,\"mute\": false,\"strict_conflict\": false}" \
	    --header "Content-Type: application/octet-stream" \
	    --data-binary @$1)
	#echo $FINISH | jq .
	UPLOADTIME=$(echo $FINISH | jq -r .server_modified)
	if [ ! -z $UPLOADTIME ] ; then
		echo "Successfully uploaded!"
	else
		echo "Unknown error when uploading..."
	fi
}

# RUN CHECKS AND IF PASS, EXECUTE BACKUP TO DROPBOX
run_dropbox_backup () {
	dropbox_upload_check
	if [ $UPLOAD_TO_DROPBOX = true ] ; then
		upload_to_dropbox $1
	fi
}


##############
# RUN SCRIPT
##############

run_backup_on_change () {
	    echo "Copying backup file..."
	    cp $SOURCEFILE $BACKUPFILE
	    md5sum $SOURCEFILE > $BACKUPFILE.md5
	    sed -i 's/\/.*\///g' $BACKUPFILE.md5

	    echo
	    echo "Uploading backup file: '"${BACKUPFILE}"'..."
	    run_dropbox_backup $BACKUPFILE
	    echo "---"
	    echo "Uploading signature: '"${BACKUPFILE}.md5"'..."
	    run_dropbox_backup $BACKUPFILE.md5
}

run () {
	inotifycheck
	setup_files_and_folders
	while true; do
	    inotifywait $SOURCEFILE
	    run_backup_on_change
	    echo
	done
}

run