systemd.rs

//! Systemd integration via `sd_notify`
//! See <https://www.freedesktop.org/software/systemd/man/latest/sd_notify.html>

use tokio::time::interval;

/// Sends `READY=1` to systemd via sd_notify. No-op if not Type=notify.
pub fn sd_notify_ready() {
    if let Err(error) = sd_notify::notify(&[sd_notify::NotifyState::Ready]) {
        warn!(message = "Failed to notify systemd of ready state.", %error);
    }
}

/// Sends `STOPPING=1` to systemd via sd_notify. No-op if not Type=notify.
pub fn sd_notify_stopping() {
    if let Err(error) = sd_notify::notify(&[sd_notify::NotifyState::Stopping]) {
        warn!(message = "Failed to notify systemd of stopping state.", %error);
    }
}

/// Sends `WATCHDOG=1` to systemd via sd_notify. No-op if not Type=notify.
pub fn sd_notify_watchdog() {
    if let Err(error) = sd_notify::notify(&[sd_notify::NotifyState::Watchdog]) {
        warn!(message = "Failed to send systemd watchdog ping.", %error);
    }
}

/// Sends `WATCHDOG=1` pings at half the `WatchdogSec` interval. No-op if not set.
pub async fn watchdog() {
    let Some(duration) = sd_notify::watchdog_enabled() else {
        return;
    };
    let mut ticker = interval(duration / 2);
    loop {
        ticker.tick().await;
        sd_notify_watchdog();
    }
}

#[cfg(test)]
mod tests {
    #[test]
    fn sd_notify_no_socket_does_not_panic() {
        // NOTIFY_SOCKET is not set in test environments - these must be no-ops.
        super::sd_notify_ready();
        super::sd_notify_stopping();
        super::sd_notify_watchdog();
    }
}