A nice little playbook to get ansible to set up syncthing for oneself on an SSH-accessible computer. Depends on @classicsc's nice python module: https://github.com/classicsc/syncthingmanager. Thanks alot!

.configure-syncthing.yaml

---
- hosts: all
  # run this: ansible-playbook -i lil_box.local, -u $USER .configure-syncthing.yaml --ask-become-pass
  # beforehand you need to:
    # ssh-copy-id -i $remoteserver
    # as well as:
    # ssh-copy-id -i localhost

  vars:
    sync_dir: "{{ ansible_env.HOME }}/Sync"

  tasks:

  - name: install necessary packages
    apt: pkg={{ item }} update_cache=yes cache_valid_time=3600
    become: yes
    with_items:
      - syncthing

  - name: install pip3 packages
    pip: name={{ item }} extra_args="--upgrade" executable=pip3
    become: yes
    with_items:
      - syncthingmanager

  - name: configure device
    command: stman configure 
    args:
      creates: "{{ ansible_env.HOME }}/.config/syncthingmanager/syncthingmanager.conf"

  - name: get locally configured devices
    shell: stman device list
    delegate_to: localhost
    register: local_devices

  - name: get remotely configured devices
    command: stman device list
    register: remote_devices

  - name: get DEVICEIDs
    set_fact:
      lil_box_deviceid: "{{ remote_devices.stdout_lines[1].split()[1] }}"
      big_box_deviceid: "{{ local_devices.stdout_lines[1].split()[1] }}"

  - name: investigate
    debug:
      var: lil_box_deviceid
      # var: local_devices

  - name: investigate
    debug:
      msg: "Already added {{ big_box_deviceid }} remotely"
    when: big_box_deviceid in remote_devices.stdout

  - name: add {{ big_box_deviceid }}
    command: stman device add -i {{ big_box_deviceid }}
    register: res_big_box
    when: big_box_deviceid not in remote_devices.stdout

  - name: add default folder remotely
    command: stman folder add {{ sync_dir }} default
    args:
      creates: "{{ sync_dir }}"

  - name: add remote device locally
    shell: stman device add {{ lil_box_deviceid }} 
    delegate_to: localhost
    register: res_local
    when: lil_box_deviceid not in local_devices.stdout

  - name: get shared local folders
    shell: stman folder list
    delegate_to: localhost
    register: local_folders

  - name: share local default folder remote device 
    shell: stman folder share default {{ lil_box_deviceid }} 
    delegate_to: localhost
    when: "ansible_hostname not in local_folders.stdout_lines[1]"
    # when: lil_box_deviceid in local_devices.stdout or res_local.failed is defined and not res_local.failed

  - name: restart syncthing
    systemd: name=syncthing state=restarted enabled=yes user=yes