Tutorial

Before starting, consider if you actually need vdirsyncer. There are better alternatives available for particular usecases.

Installation

See Installation.

Configuration

Note

  • The config.example from the repository contains a very terse version of this.
  • In this example we set up contacts synchronization, but calendar sync works almost the same. Just swap type = "carddav" for type = "caldav" and fileext = ".vcf" for fileext = ".ics".
  • Take a look at the Known Problems page if anything doesn’t work like planned.

By default, vdirsyncer looks for its configuration file in the following locations:

  • The file pointed to by the VDIRSYNCER_CONFIG environment variable.
  • ~/.vdirsyncer/config.
  • $XDG_CONFIG_HOME/vdirsyncer/config, which is normally ~/.config/vdirsyncer/config. See the XDG-Basedir specification.

The config file should start with a general section, where the only required parameter is status_path. The following is a minimal example:

[general]
status_path = "~/.vdirsyncer/status/"

After the general section, an arbitrary amount of pair and storage sections might come.

In vdirsyncer, synchronization is always done between two storages. Such storages are defined in storage sections, and which pairs of storages should actually be synchronized is defined in pair section. This format is copied from OfflineIMAP, where storages are called repositories and pairs are called accounts.

The following example synchronizes addressbooks from a NextCloud to ~/.contacts/:

[pair my_contacts]
a = "my_contacts_local"
b = "my_contacts_remote"
collections = ["from a", "from b"]

[storage my_contacts_local]
type = "filesystem"
path = "~/.contacts/"
fileext = ".vcf"

[storage my_contacts_remote]
type = "carddav"

# We can simplify this URL here as well. In theory it shouldn't matter.
url = "https://nextcloud.example.com/"
username = "bob"
password = "asdf"

Note

Configuration for other servers can be found at Servers.

After running vdirsyncer discover and vdirsyncer sync, ~/.contacts/ will contain subfolders for each addressbook, which in turn will contain a bunch of .vcf files which all contain a contact in VCARD format each. You can modify their contents, add new ones and delete some [1], and your changes will be synchronized to the CalDAV server after you run vdirsyncer sync again. For further reference, it uses the storages filesystem and carddav.

However, if new collections are created on the server, it will not automatically start synchronizing those [2]. You need to run vdirsyncer discover again to re-fetch this list instead.

[1]You’ll want to use a helper program for this.
[2]Because collections are added rarely, and checking for this case before every synchronization isn’t worth the overhead.

More Configuration

Conflict resolution

What if the same item is changed on both sides? What should vdirsyncer do? Three options are currently provided:

  1. vdirsyncer displays an error message (the default);
  2. vdirsyncer chooses one alternative version over the other;
  3. vdirsyncer starts a command of your choice that is supposed to merge the two alternative versions.

Options 2 and 3 require adding a "conflict_resolution" parameter to the pair section. Option 2 requires giving either "a wins" or "b wins" as value to the parameter:

[pair my_contacts]
...
conflict_resolution = "b wins"

Earlier we wrote that b = "my_contacts_remote", so when vdirsyncer encounters the situation where an item changed on both sides, it will simply overwrite the local item with the one from the server.

Option 3 requires specifying as value of "conflict_resolution" an array starting with "command" and containing paths and arguments to a command. For example:

[pair my_contacts]
...
conflict_resolution = ["command", "vimdiff"]

In this example, vimdiff <a> <b> will be called with <a> and <b> being two temporary files containing the conflicting files. The files need to be exactly the same when the command returns. More arguments can be passed to the command by adding more elements to the array.

See Pair Section for the reference documentation.

Metadata synchronization

Besides items, vdirsyncer can also synchronize metadata like the addressbook’s or calendar’s “human-friendly” name (internally called “displayname”) or the color associated with a calendar. For the purpose of explaining this feature, let’s switch to a different base example. This time we’ll synchronize calendars:

[pair my_calendars]
a = "my_calendars_local"
b = "my_calendars_remote"
collections = ["from a", "from b"]
metadata = ["color"]

[storage my_calendars_local]
type = "filesystem"
path = "~/.calendars/"
fileext = ".ics"

[storage my_calendars_remote]
type = "caldav"

url = "https://nextcloud.example.com/"
username = "bob"
password = "asdf"

Run vdirsyncer discover for discovery. Then you can use vdirsyncer metasync to synchronize the color property between your local calendars in ~/.calendars/ and your NextCloud. Locally the color is just represented as a file called color within the calendar folder.

More information about collections

“Collection” is a collective term for addressbooks and calendars. Each collection from a storage has a “collection name”, a unique identifier for each collection. In the case of filesystem-storage, this is the name of the directory that represents the collection, in the case of the DAV-storages this is the last segment of the URL. We use this identifier in the collections parameter in the pair-section.

This identifier doesn’t change even if you rename your calendar in whatever UI you have, because that only changes the so-called “displayname” property [3]. On some servers (iCloud, Google) this identifier is randomly generated and has no correlation with the displayname you chose.

[3]Which you can also synchronize with metasync using metadata = ["displayname"].

There are three collection names that have a special meaning:

  • "from a", "from b": A placeholder for all collections that can be found on side A/B when running vdirsyncer discover.
  • null: The parameters give to the storage are exact and require no discovery.

The last one requires a bit more explanation. Assume this config which synchronizes two directories of addressbooks:

[pair foobar]
a = "foo"
b = "bar"
collections = ["from a", "from b"]

[storage foo]
type = "filesystem"
fileext = ".vcf"
path = "./contacts_foo/"

[storage bar]
type = "filesystem"
fileext = ".vcf"
path = "./contacts_bar/"

As we saw previously this will synchronize all collections in ./contacts_foo/ with each same-named collection in ./contacts_bar/. If there’s a collection that exists on one side but not the other, vdirsyncer will ask whether to create that folder on the other side.

If we set collections = null, ./contacts_foo/ and ./contacts_bar/ are no longer treated as folders with collections, but as collections themselves. This means that ./contacts_foo/ and ./contacts_bar/ will contain .vcf-files, not subfolders that contain .vcf-files.

This is useful in situations where listing all collections fails because your DAV-server doesn’t support it, for example. In this case, you can set url of your carddav- or caldav-storage to a URL that points to your CalDAV/CardDAV collection directly.

Note that not all storages support the null-collection, for example google_contacts and google_calendar don’t.

Advanced collection configuration (server-to-server sync)

The examples above are good enough if you want to synchronize a remote server to a previously empty disk. However, even more trickery is required when you have two servers with already existing collections which you want to synchronize.

The core problem in this situation is that vdirsyncer pairs collections by collection name by default (see definition in previous section, basically a foldername or a remote UUID). When you have two servers, those collection names may not line up as nicely. Suppose you created two calendars “Test”, one on a NextCloud server and one on iCloud, using their respective web interfaces. The URLs look something like this:

NextCloud: https://example.com/remote.php/dav/calendars/user/test/
iCloud:    https://p-XX.caldav.icloud.com/YYY/calendars/3b4c9995-5c67-4021-9fa0-be4633623e1c

Those are two DAV calendar collections. Their collection names will be test and 3b4c9995-5c67-4021-9fa0-be4633623e1c respectively, so you don’t have a single name you can address them both with. You will need to manually “pair” (no pun intended) those collections up like this:

[pair doublecloud]
a = "my_nextcloud"
b = "my_icloud"
collections = [["mytest", "test", "3b4c9995-5c67-4021-9fa0-be4633623e1c"]]

mytest gives that combination of calendars a nice name you can use when talking about it, so you would use vdirsyncer sync doublecloud/mytest to say: “Only synchronize these two storages, nothing else that may be configured”.

Note

Why not use displaynames?

You may wonder why vdirsyncer just couldn’t figure this out by itself. After all, you did name both collections “Test” (which is called “the displayname”), so why not pair collections by that value?

There are a few problems with this idea:

  • Two calendars may have the same exact displayname.
  • A calendar may not have a (non-empty) displayname.
  • The displayname might change. Either you rename the calendar, or the calendar renames itself because you change a language setting.

In the end, that property was never designed to be parsed by machines.