www/content/blog/ansible/syncthing-ansible-role.md

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---
title: Syncthing ansible role
date: 2023-01-21
description: The ansible role I wrote to manage my syncthing configurations
tags:
- ansible
- syncthing
---
## Introduction
I have been using [syncthing](https://syncthing.net/) for some time now. It is a tool to handle bidirectional synchronisation of data. For example I use it on my personal infrastructure to synchronise:
- org-mode files between my workstation, laptop, a server and my phone (I need those everywhere!)
- pictures from my phone and my nas
- my music collection between my phone and my nas
It is very useful, but by default the configuration leave a few things to be desired like telemetry or information leaks. If you want maximum privacy you need to disable the autodiscovery and the default nat traversal features.
Also provisioning is easy, but deleting or unsharing stuff would require to remember what is shared where and go manage each device individualy from syncthing's web interface. I automated all that with ansible (well except for my phone which I cannot manage with ansible, its syncthing configuration will remain manual... for now).
## Why another ansible role
I wanted a role to install and configure syncthing for me and did not find an existing one that satisfied me. I had a few mandatory features in mind:
- the ability to configure a servers parameters in only one place to avoid repetition
- having a fact that retrieves the ID of a device
- the validation of host_vars which virtually no role in the wild ever does
- the ability to manage an additional inventory file for devices which ansible cannot manage (like my phone)
## Role variables
There is a single variable to specify in the `host_vars` of your hosts: `syncthing`. This is a dict that can contain the following keys:
- address: optional string to specify how to connect to the server, must match the format `tcp://<hostname>` or `tcp://<ip>`. Default value is *dynamic* which means a passive host.
- shared: a mandatory dict describing the directories this host shares, which can contain the following keys:
- name: a mandatory string to name the share in the configuration. It must match on all devices that share this folder.
- path: the path of the folder on the device. This can difer on each device sharing this data.
- peers: a list a strings. Each item should be either the ansible_hostname of another device, or a hostname from the `syncthing_data.yaml` file
Configuring a host through its `host_vars` looks like this:
```yaml
syncthing:
address: tcp://lore.adyxax.org
shared:
- name: org-mode
path: /var/syncthing/org-mode
peers:
- hero
- light
- lumapps
- Pixel 3a
```
## The optional syncthing_data.yaml file
To be found by the `action_plugins`, this file should be in the same folder as your playbook. It shares the same format as the `host_vars` but with additional keys for the hostname and its ID.
The data file for non ansible devices looks like this:
```yaml
- name: Pixel 3a
id: ABCDEFG-HIJKLMN-OPQRSTU-VWXYZ01-2345678-90ABCDE-FGHIJKL-MNOPQRS
shared:
- name: Music
path: /storage/emulated/0/Music
peers:
- phoenix
- name: Photos
path: /storage/emulated/0/DCIM/Camera
peers:
- phoenix
- name: org-mode
path: /storage/emulated/0/Org
peers:
- lore.adyxax.org
```
## Example playbook
```yaml
- hosts: all
roles:
- { role: syncthing, tags: [ 'syncthing' ], when: "syncthing is defined" }
```
## Conclusion
You can find the role [here](https://git.adyxax.org/adyxax/syncthing-ansible-role/about/). If I left something unclear or some piece seems to be missing, do not hesitate to [contact me]({{< ref "about-me.md" >}}).