Monorepo for Tangled
tangled.org
shuttle: wait for nix-daemon pids to be gone before waiting for the restarted one
Signed-off-by: dawn <dawn@tangled.org>
author
dawn
date
(Jun 27, 2026, 3:19 PM +0300)
commit
9824c1d4
9824c1d4223f54ffa925f783b2f836d2780f9ff9
parent
c7c025ca
c7c025cad18950be1ac863e1fd7ce080a8fa2111
change-id
xknzlswq
xknzlswqwzrltwwtmsuzunstwvlvursn
+60
-25
+60
-25
shuttle/src/nix_config.rs
+60
-25
shuttle/src/nix_config.rs
···
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use crate::command::{self, Spec};
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use crate::protocol::v1;
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use anyhow::{Context, Result};
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use nix::sys::signal::{self, Signal};
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use nix::unistd::Pid;
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use serde::{Deserialize, Serialize};
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use std::collections::HashSet;
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use std::fmt::Write as _;
···
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const NIX_DAEMON_SOCKET: &str = "/nix/var/nix/daemon-socket/socket";
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async fn restart_nix_daemon() {
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let systemd = Path::new(SYSTEMCTL_EXECUTABLE).exists();
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let spec = if systemd {
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Spec::new(SYSTEMCTL_EXECUTABLE)
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if Path::new(SYSTEMCTL_EXECUTABLE).exists() {
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let spec = Spec::new(SYSTEMCTL_EXECUTABLE)
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.args(["try-restart", "nix-daemon.service"])
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.timeout(Duration::from_secs(5))
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} else {
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// on non-systemd we can just kill the daemon and it should restart
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Spec::new("pkill")
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.args(["-f", "nix-daemon"])
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.timeout(Duration::from_secs(5))
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.timeout(Duration::from_secs(5));
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match command::run_capture(spec).await {
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Ok(output) if output.success() => {}
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Ok(output) => warn!(
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exit_code = output.exit.exit_code,
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error = ?output.exit.error,
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output = %output.combined_lossy(),
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"nix-daemon restart failed"
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),
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Err(error) => warn!(%error, "nix-daemon restart failed"),
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}
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return;
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}
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let old_pids = nix_daemon_pids();
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if old_pids.is_empty() {
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info!("no nix-daemon running, skipping restart");
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return;
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}
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for pid in &old_pids {
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if let Err(error) = signal::kill(*pid, Signal::SIGTERM) {
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warn!(%error, pid = pid.as_raw(), "failed to signal nix-daemon");
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}
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}
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// wait for nix daemon to be gone, kill is not sync
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wait_pids_gone(&old_pids, Duration::from_secs(5)).await;
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wait_for_nix_daemon_socket(Duration::from_secs(5)).await;
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}
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fn nix_daemon_pids() -> Vec<Pid> {
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let self_pid = std::process::id();
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let Ok(entries) = fs::read_dir("/proc") else {
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return Vec::new();
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};
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entries
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.flatten()
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.filter_map(|entry| {
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let pid = entry.file_name().to_str()?.parse::<i32>().ok()?;
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if pid as u32 == self_pid {
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return None;
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}
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let comm = fs::read_to_string(entry.path().join("comm")).ok()?;
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(comm.trim() == "nix-daemon").then(|| Pid::from_raw(pid))
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})
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.collect()
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}
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match command::run_capture(spec).await {
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Ok(output) if output.success() => {
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if !systemd {
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// init has to respawn the daemon before any step needs it
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wait_for_nix_daemon_socket(Duration::from_secs(5)).await;
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}
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async fn wait_pids_gone(pids: &[Pid], timeout: Duration) {
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let deadline = tokio::time::Instant::now() + timeout;
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loop {
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// signal 0 only checks for existence; Err (ESRCH) means it's gone
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if !pids.iter().any(|pid| signal::kill(*pid, None).is_ok()) {
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return;
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}
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// pkill exits 1 when nothing matched, ie. no daemon to restart
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Ok(output) if !systemd && output.exit.exit_code == 1 => {
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info!("no nix-daemon running, skipping restart")
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if tokio::time::Instant::now() >= deadline {
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warn!("old nix-daemon did not exit before restart timeout");
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return;
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}
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Ok(output) => warn!(
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exit_code = output.exit.exit_code,
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error = ?output.exit.error,
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output = %output.combined_lossy(),
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"nix-daemon restart failed"
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),
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Err(error) => warn!(%error, "nix-daemon restart failed"),
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tokio::time::sleep(Duration::from_millis(10)).await;
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}
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}
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