← Otto User GuideAutostarting Applications

Otto supports three complementary approaches for launching applications automatically at startup. Choose the one that best fits your workflow — or combine them.

Config Reference

1. exec_once — Run Commands at Startup

The simplest option. Define a list of commands in your Otto config file and they will be spawned once, in order, when the compositor is ready.

# ~/.config/otto/config.toml

[[exec_once]]
cmd = "waybar"
args = []

[[exec_once]]
cmd = "dunst"
args = []

[[exec_once]]
cmd = "wlsunset"
args = ["-l", "48.8", "-L", "2.3"]

Each entry takes:

Entries are spawned non-blocking (fire-and-forget) in listed order. Otto calls spawn() sequentially but does not wait for any process to become ready before launching the next — there is no startup ordering or readiness guarantee between entries.

Environment

Each spawned process inherits the compositor’s environment with the following additions:

Best for: personal dotfiles, simple setups, or apps you always want running.

Limitation: Otto does not restart crashed processes. Use a supervisor (systemd, s6, runit) if you need that.

2. XDG Autostart Entries

Otto can respect the XDG Autostart specification, reading .desktop files from standard autostart directories.

Enable it in your config:

xdg_autostart = true

Directory Scan Order

Otto scans directories in this order — later entries override earlier ones by filename:

1. System dirs — each directory in $XDG_CONFIG_DIRS (defaults to /etc/xdg), with /autostart appended

   /etc/xdg/autostart/*.desktop
   

2. User dir — $XDG_CONFIG_HOME/autostart (defaults to ~/.config/autostart)

   ~/.config/autostart/*.desktop
   

If a user entry has the same filename as a system entry, the user entry takes precedence.

Filtering Rules

Otto implements the full XDG autostart filtering spec:

The desktop environment name matched is Otto (case-insensitive).

Example

~/.config/autostart/mako.desktop:

[Desktop Entry]
Type=Application
Name=Mako
Exec=mako
Hidden=false

Best for: distro-managed or shared configurations, apps that ship their own .desktop autostart file.

3. Systemd User Services

The most robust approach for production setups. Otto integrates with systemd --user to signal readiness and activate the graphical-session.target, allowing dependent services to start in the correct order.

Enabling systemd Integration

Any of these three methods will enable systemd notify:

# Option A: config file
systemd_notify = true

# Option B: CLI flag
otto --tty-udev --systemd-notify

# Option C: environment variable
OTTO_SYSTEMD_NOTIFY=1 otto --tty-udev

What Happens at Startup

When systemd notify is enabled, Otto performs these steps after the Wayland socket is listening:

1. Exports WAYLAND_DISPLAY to the systemd user session (systemctl --user set-environment)
2. Sends READY=1 via sd_notify
3. Runs systemctl --user start graphical-session.target

Example: Otto as a Systemd Service

Create ~/.config/systemd/user/otto.service:

[Unit]
Description=Otto Wayland Compositor
After=systemd-user-sessions.service

[Service]
Type=notify
ExecStart=/usr/bin/otto --tty-udev --systemd-notify
Restart=on-failure

[Install]
WantedBy=default.target

Enable and start:

systemctl --user enable otto.service
systemctl --user start otto.service

Depending on Otto from Other Services

Once Otto activates graphical-session.target, other user services can depend on it:

# ~/.config/systemd/user/waybar.service
[Unit]
Description=Waybar status bar
After=graphical-session.target
PartOf=graphical-session.target

[Service]
ExecStart=/usr/bin/waybar

[Install]
WantedBy=graphical-session.target

Best for: production installations, multi-user systems, services that need strict startup ordering or automatic restart.

Combining Approaches

The three methods are not mutually exclusive. A common setup:

Execution Order

1. Wayland socket becomes ready
2. WAYLAND_DISPLAY is exported to systemd
3. sd_notify(READY=1) is sent (if enabled)
4. graphical-session.target is activated (if enabled)
5. exec_once entries are spawned in order
6. XDG autostart entries are launched (if enabled)