Add the ability to sync backup schedule with Plex DB backup

[tim-shortons]

Plex runs DB backups every three days and you can't schedule this in cron without some additional logic.

I have a small script that does the following. Take the current date, subtract the original plex DB execution date, determine if it has been three days and if so run the back up script. This cron job runs every day, but it will only execute on a three day cadence when the modulo evaluation returns 0.

days=$(( ($(date +\%s) - $(date -d "2024-12-19" +\%s) ) / 86400 % 3));
        if [ "$days" == 0 ];
                then echo "$days number of days" && /scripts/plex_backup/linux_plex_backup.sh;
        else echo "$days";
        fi

Perhaps this can be incorporated into the script? I can see a simple param driven approach where you set your first day of plex backup as a date variable in the config file and it uses that date to determine if it has been three days to run the backup. This is rather inflexible and if for some reason the plex DB backup gets out of schedule you would need to manually update the script or config file, depending on implementation.

Another option that would be more flexible would be to parse the plex DB filename for the date value and evaluate if that date is equal to the current date and if so run the backup script.

[007revad]

Another option that would be more flexible would be to parse the plex DB filename for the date value and evaluate if that date is equal to the current date and if so run the backup script.

This would be my preferred method, but I see a potential problem. If the script runs on the same day that Plex backs up it's database, but the script runs before Plex does it's backup then the script won't do a backup that day. So the script would never do a backup.

The solution to this would be to ignore the actual date and just check if Plex has done a DB backup within the last 24 hours.

[007revad]

I just searched com.plexapp.system.log and com.plexapp.system.log.1 and there is no mention of com.plexapp.plugins.library.db or com.plexapp.plugins.library.blobs.db

[007revad]

I've been testing checking if the DB backup is less than 24 hours old with this and it seems to work correctly:

#!/usr/bin/env bash

days=1

# Get epoch in seconds
now=$(date +%s)

# Set threshold to days x seconds in a day
threshold=$((days *86400))

check_if_older(){ 
    # Get last access time in epoch
    mtime=$(stat -c %X "$1")
    # Get last access time human readable
    mtimehr=$(stat -c %x "$1")

    echo "$(basename -- "$1")"

    # Check if not accessed in "$days"
    if [[ $((now -mtime)) -lt "$threshold" ]]; then
        echo -e "Starting backup: ${mtimehr%.*}\n"
    else                                            # debug
        echo -e "Skipping backup: ${mtimehr%.*}\n"  # debug
    fi
}

plex_location="/var/lib/plexmediaserver/Library/Application Support/Plex Media Server"

check_if_older "$plex_location/Plug-in Support/Databases/com.plexapp.plugins.library.db-2025-01-01"
check_if_older "$plex_location/Plug-in Support/Databases/com.plexapp.plugins.library.db-2024-12-29"

[007revad]

Do you want to test this.

It should echo "Starting backup" if the latest Plex db backup was less than 24 hours ago.
Otherwise echo "Skipping backup".

There'll be a yes/no option in the config file to enable/disable this feature. I can't think of good name for it so for now I'm calling it db_sync.

#!/usr/bin/env bash

Plex_Data_Path="/var/lib/plexmediaserver/Library/Application Support"

db_sync=yes

if [[ $db_sync == "yes" ]]; then
    # Get name of latest Plex db backup
    dbpath="${Plex_Data_Path}/Plex Media Server/Plug-in Support/Databases"
    latest_db="$(find "$dbpath" -maxdepth 1 -type f -name "com.plexapp.plugins.library.db-2*" | sort | tail -n 1)"

    # Show latest db filename
    echo -e "\n$(basename -- "$latest_db")"

    # Get current epoch in seconds
    now=$(date +%s)

    # Threshold is number of seconds in a day
    threshold="86400"

    # Get last modified time in epoch
    filetime=$(stat -c %Y "$latest_db")
    # Get last modified time human readable
    filetimehr=$(stat -c %y "$latest_db")

    # Check if modified in the last 24 hours
    if [[ $((now -filetime)) -lt "$threshold" ]]; then
        echo -e "Starting backup: ${filetimehr%.*}\n"
    else
        echo -e "Skipping backup: ${filetimehr%.*}\n"
        exit
    fi
fi

[tim-shortons]

I ran a quick test and it seems to be working, ran against an several day old DB, returned skipping backup. I then created a new file and received a starting backup message. Going to add an email output and schedule it cron to see how it behaves, but I have no reason to believe it won't work as intended.

Thank you for making these updates and apologies for not being able to bring more to the table. I can somewhat understand scripts and do simple stuff, but that's about the extent of my capabilities.

[tim-shortons]

@007revad

So far your check appears to be working as expected. I had a thought, and let me know if I am over complicating things. but in the script you created the user can set a threshold and the script evaluates to determine if the filetime is less than this threshold. Unfortunately plex doesn't allow the end user to select the DB backup execution time and it is possible, if someone isn't paying attention to their cron scheduling, they could have this script run during the plex DB backup.

 # Threshold is number of seconds in a day
    threshold="86400"

 # Check if modified in the last 24 hours
    if [[ $((now -filetime)) -lt "$threshold" ]]; then
        echo -e "Starting backup: ${filetimehr%.*}\n"
    else
        echo -e "Skipping backup: ${filetimehr%.*}\n"
        exit
    fi

Is it worth the time/effort to incorporate a check to confirm the plex DB file is no longer building? Perhaps this is one of those cases where it is incumbent upon the user to make sure they understand when their jobs are executing.

#!/bin/bash

function is_file_building() {
  local file="$1"

  # Check if the file exists
  if [ ! -f "$file" ]; then
    return 1 # File does not exist
  fi

  # Check if the file size is changing
  local old_size=$(stat -c %s "$file")
  sleep 1 # Wait for a short period
  local new_size=$(stat -c %s "$file")

  if [ "$old_size" -ne "$new_size" ]; then
    return 0 # File is likely building
  else
    return 1 # File size is not changing
  fi
}

# Get name of latest Plex db backup
Plex_Data_Path="/var/lib/plexmediaserver/Library/Application Support"
dbpath="${Plex_Data_Path}/Plex Media Server/Plug-in Support/Databases"
latest_db="$(find "$dbpath" -maxdepth 1 -type f -name "com.plexapp.plugins.library.db-2*" | sort | tail -n 1)"
#latest_db="/home/user/Downloads/incomplete/test_download_10GB/sometestfile-10GB.part05.rar"

# Example usage:
if is_file_building "$latest_db"; then
  echo "File is building - $(basename -- "$latest_db")"
else
  echo "File is not building - $(basename -- "$latest_db")"
fi