File Versioning

Description

Syncthing supports archiving the old version of a file when it is deleted or replaced with a newer version from the cluster. This is called “file versioning” and uses one of the available versioning strategies described below. File versioning is configured per folder, on a per-device basis, and defaults to “no file versioning”, i.e. no old copies of files are kept.

Trash Can File Versioning

This versioning strategy emulates the common “trash can” approach. When a file is deleted or replaced due to a change on a remote device, it is a moved to the trash can in the .stversions folder. If a file with the same name was already in the trash can it is replaced.

A configuration option is available to clean the trash can from files older than a specified number of days. If this is set to a positive number of days, files will be removed when they have been in the trash can that long. Setting this to zero prevents any files from being removed from the trash can automatically.

Simple File Versioning

With “Simple File Versioning” files are moved to the .stversions folder (inside your shared folder) when replaced or deleted on a remote device. This option also takes a value in an input titled “Keep Versions” which tells Syncthing how many old versions of the file it should keep. For example, if you set this value to 5, if a file is replaced 5 times on a remote device, you will see 5 time-stamped versions on that file in the ”.stversions” folder on the other devices sharing the same folder.

Staggered File Versioning

With “Staggered File Versioning” files are also moved to a different folder when replaced or deleted on a remote device (just like “Simple File Versioning”), however, versions are automatically deleted if they are older than the maximum age or exceed the number of files allowed in an interval.

With this versioning method it’s possible to specify where the versions are stored, with the default being the .stversions folder inside the normal folder path. If you set a custom version path, please ensure that it’s on the same partition or filesystem as the regular folder path, as moving files there may otherwise fail. You can use an absolute path (this is recommended) or a relative path. Relative paths are interpreted relative to Syncthing’s current or startup directory.

The following intervals are used and they each have a maximum number of files that will be kept for each.

1 Hour
For the first hour, the most recent version is kept every 30 seconds.
1 Day
For the first day, the most recent version is kept every hour.
30 Days
For the first 30 days, the most recent version is kept every day.
Until Maximum Age
Until maximum age, the most recent version is kept every week.
Maximum Age
The maximum time to keep a version in days. For example, to keep replaced or deleted files in the ”.stversions” folder for an entire year, use 365. If only for 10 days, use 10. Note: Set to 0 to keep versions forever.

External File Versioning

This versioning method delegates the decision on what to do to an external command (program or script). Just prior to a file being replaced, the command will be run. The command should be specified as an absolute path, and can use the following templated arguments:

%FOLDER_PATH%
Path to the folder
%FILE_PATH%
Path to the file within the folder

Example for Unixes

Lets say I want to keep the latest version of each file as they are replaced or removed; essentially I want a “trash can”-like behavior. For this, I create the following script and store it as /Users/jb/bin/onlylatest.sh (i.e. the bin directory in my home directory):

#!/bin/sh
set -eu

# Where I want my versions stored
versionspath=~/.trashcan

# The parameters we get from Syncthing
folderpath="$1"
filepath="$2"

# First ensure the dir where we need to store the file exists
outpath=`dirname "$versionspath/$filepath"`
mkdir -p "$outpath"
# Then move the file there
mv -f "$folderpath/$filepath" "$versionspath/$filepath"

I must ensure that the script has execute permissions (chmod 755 onlylatest.sh), then configure Syncthing with command /Users/jb/bin/onlylatest.sh %FOLDER_PATH% %FILE_PATH%

Lets assume I have a folder “default” in ~/Sync, and that within that folder there is a file docs/letter.txt that is being replaced or deleted. The script will be called as if I ran this from the command line:

$ /Users/jb/bin/onlylatest.sh /Users/jb/Sync docs/letter.txt

The script will then move the file in question to ~/.trashcan/docs/letter.txt, replacing any previous version of that letter that may already have been there.

Example for Windows

On Windows we can use a batch script to perform the same “trash can”-like behavior as mentioned above. I created the following script and saved it as C:\Users\mfrnd\Scripts\onlylatest.bat.

@echo off

:: We need command extensions for mkdir to create intermediate folders in one go
setlocal EnableExtensions

:: Where I want my versions stored
set VERSIONS_PATH=%USERPROFILE%\.trashcan

:: The parameters we get from Syncthing, '~' removes quotes if any
set FOLDER_PATH=%~1
set FILE_PATH=%~2

:: First ensure the dir where we need to store the file exists
for %%F in ("%VERSIONS_PATH%\%FILE_PATH%") do set OUTPUT_PATH=%%~dpF
if not exist "%OUTPUT_PATH%" mkdir "%OUTPUT_PATH%" || exit /B

:: Finally move the file, overwrite existing file if any
move /Y "%FOLDER_PATH%\%FILE_PATH%" "%VERSIONS_PATH%\%FILE_PATH%"

Finally, I set C:\Users\mfrnd\Scripts\onlylatest.bat %FOLDER_PATH% %FILE_PATH% as command name in Syncthing.