Listen on the socket systemd hands over, so a restart never answers 502 (#169)

OP OpenVibers committed 13 days ago · 8e062a0f49 · 1 file, +4 −1

When the service is socket-activated (LISTEN_FDS=1 for this process), it listens on fd 3, the listener a
systemd .socket unit holds across restarts: requests that arrive during a deploy wait in the kernel's accept
queue and are served by the new process. Without the socket unit it listens on its port as before. The same
three lines Network, Media, Chat and Live use. 2026-10-31: a Codes deploy gave the owner a Cloudflare 502.

Changes

ddiff --git a/server/index.js b/server/index.js
iindex 48ed01c..2cd8cad 100644
---- a/server/index.js
++++ b/server/index.js
@@@ -150,7 +150,10 @@ async function start({
      let server = null;
      if (listen) {
          server = await new Promise((resolve, reject) => {
--            const s = app.listen(config.port, config.host, () => resolve(s));
++            // Socket activation (2026-10-31): systemd's .socket unit holds the listener across restarts, so a deploy
++            // queues requests in the kernel instead of answering 502. Without the socket unit, the usual listen.
++            const socketActivated = process.env.LISTEN_FDS === '1' && Number(process.env.LISTEN_PID) === process.pid;
++            const s = app.listen(...(socketActivated ? [{ fd: 3 }] : [config.port, config.host]), () => resolve(s));
              s.on('error', reject);
          });
          // SSE connections stay open; Node's default keep-alive/header timers only affect idle sockets.