Suggestion: Change recommendation for cron to systemd

Hi again,

I wondered why you were recommending cron for this task. I find it could easily lead to a conflicting state if the repeating window isn’t small enough (and then there’s a lot of unnecessary syncs).

I’m mainly curious to know your reasons so feel free to close this issue.

I’ve tried to get this right using systemd executing a script on startup that first triggers a sync and afterwards syncs on changes monitored with inotifywait.

rclonesync_watch.service

# /home/3ter/.config/systemd/user/rclone-sync-gdrive.service
[Unit]
Description=Sync Googledrive with the local folder on startup and on change afterwards

[Service]
ExecStart=/usr/bin/perl /home/3ter/scripts/rclonesync_watch.pl

[Install]
WantedBy=default.target

rclonesync_watch.pl

#!/bin/perl

use strict;
use warnings;
use v5.30;

our $local_dir      = '/home/3ter/googledrive';
our $remote_dir     = 'googledrive:/';
our $rclonesync_exe = '/home/3ter/rclonesync/rclonesync.py';
our $inotify_opts   = 
    "--event " .
    join(' --event ', qw(modify attrib close_write moved_to create delete)) .
    " --recursive $local_dir";

sub wait_until_file_silent
    {
    while (1)
        {
        my $rc = system( "inotifywait --timeout 5 $inotify_opts" );
        # Return code 0 shows us that there was another event triggered
        return if $rc;
        }
    }

sub watch_folder
    {
    if (system( "inotifywait $inotify_opts" ) == 0)
        {
        wait_until_file_silent();
        say qx( python3 $rclonesync_exe --verbose $local_dir $remote_dir 2>&1 );
        }
    return;
    }

say '[rclone] Watching locally.';

if (-d $local_dir)
    {
    say 'Sync on startup';
    say qx( python3 $rclonesync_exe --verbose $local_dir $remote_dir 2>&1 );
    while (1)
        {
        watch_folder();
        }
    }
else
    {
    say "$local_dir isn't a valid directory!";
    }

[cjnaz]

From https://www.linuxjournal.com/content/linux-filesystem-events-inotify:

Recalcitrant users should be confined to Ultrix on a VAX until they develop sufficient appreciation for modern tools and approaches, which should result in more efficient Linux systems and happier administrators.

Sweet.

[cjnaz]

Closing this for now. My take is that rclonesync isn’t the right tool to act as a local agent and be notified and react to changes as they happen. If we had an agent it could take care of individual files that change, and not have to scan the sync tree at all.