Roster Server

RosterServer integration

Use this skill to configure a consuming application. Keep its existing configuration source, module format, and process lifecycle. Check the installed package's API when version differences matter; the upstream README may describe changes not yet installed.

Choose the lifecycle owner

• Local development: new Roster({ local: true, wwwPath: absolutePath }), register sites, then await roster.start(). Local mode binds to localhost and assigns ports; read URLs with roster.getUrl(domain) after startup.
• Standalone HTTPS: set the real email, absolute wwwPath and greenlockStorePath; leave local false. await roster.start() owns ACME HTTP on port 80 and the configured HTTPS listeners. A different HTTPS port does not eliminate the need for port 80.
• External server/worker: await roster.init(), then roster.attach(server, { port }) or an HTTPS helper. The caller owns listening and closing that server. port on attach() selects the routing table, not the TCP port.
• Serving-only worker: use autoCertificates: false with init() and createServingHttpsServer({ servername }). A separate manager must provide certificates first. Calling start() still enables the standalone ACME lifecycle.

init() invokes site factories and can write certificate configuration/start renewal work; it is not a side-effect-free inspection method. Keep domains and certificate configuration consistent across workers sharing a store. The legacy cluster: true launcher delegates process management to Greenlock; it is separate from using Roster with an external cluster manager.

Sites and routing

Register sites before init()/start(). Export a synchronous factory (virtualServer) => requestHandler; the returned (req, res) handler may be async. An Express app is a valid return value. Never call app.listen() inside the factory.

const Roster = require('roster-server');
const path = require('node:path');

const roster = new Roster({ local: true, wwwPath: path.resolve('www') });
roster.register('example.com', () => (req, res) => res.end('Hello'));

• Discovery tries index.js, index.mjs, then index.cjs; use the module format appropriate to the application's package. Without an entry script, index.html enables static serving.
• filename changes the script basename only. basePath supplies default directories; it does not rebase explicitly supplied relative paths. Prefer absolute paths.
• Discovered sites stay on HTTPS 443, even with another default port. Discovery replaces a manual registration for the same domain/port; distinct ports coexist.
• Manual register('api.example.com:8443', factory) selects that port. Exact hosts precede wildcard matches; *.example.com does not match the apex.
• Static serving streams files and supports HEAD and directory indexes, with strict missing-file 404s and no SPA fallback.
• Local ports are hash-based with in-instance collision handling, not OS availability detection. Do not hardcode example port numbers.
• Production getUrl() uses the instance's default port; it is not a per-registration custom-port lookup. A site registered only on another port can return null.

Socket.IO and asynchronous requests

Attach Socket.IO to the supplied virtual server. Return the ordinary HTTP handler and register cleanup in the same factory:

const { Server } = require('socket.io');

module.exports = (server) => {
    const io = new Server(server);
    server.onClose(() => new Promise(resolve => io.close(resolve)));
    return (req, res) => res.end('Socket.IO site');
};

Socket.IO wraps the request listeners and captures the returned handler as its fallback. Do not add a manual endpoint exclusion to that handler; use io.path() when application code needs the path. Do not use io.opts.path.

A virtual request listener owns its request even before it ends the response. Roster does not infer that an asynchronous listener declined the request. Thrown/rejected handler errors produce 500 or destroy an already-started response. Virtual servers share a process; they are not process isolation boundaries.

Shutdown

• Connect await roster.close() to the application's existing shutdown flow, or explicitly set handleSignals: true for automatic SIGINT/SIGTERM cleanup. It defaults to false; listeners are installed during init()/start() and removed after closure, including failure. Repeated signals during closure do not repeat hooks. Existing signal listeners are preserved; shutdown errors are logged and set process.exitCode = 1. Roster never forces process termination.
• Register virtualServer.onClose(fn) for each site's timers, databases, and other resources. Return/await its cleanup Promise; wrap callback APIs when needed.
• Roster signals virtual close at shutdown start to release integrations such as long polling, closes routed WebSockets, drains HTTP, then runs cleanup hooks concurrently. Put dependent cleanup steps in one hook.
• Hooks run once. Failures are aggregated after other hooks are attempted. closeTimeoutMs bounds the complete operation; timeout cannot cancel arbitrary user Promises or in-flight ACME work.
• close() is idempotent and terminal. init()/start() share concurrent calls; startup failures clean up the instance. Create a new instance after closing or failed startup.
• For attach() and both HTTPS helpers, also close the caller-owned server. Roster removes its attached listeners but does not own that server's listener lifecycle. Remove manually wired dispatchers yourself.
• Coordinate each process separately; closing an instance does not stop the legacy Greenlock cluster's worker processes.

Certificates and plugins

• Use staging: true for ACME test issuance when requested. init() alone does not bind the HTTP challenge listener.
• Wildcard certificates require DNS-01. The default CLI wrapper needs manual TXT records unless an API provider is configured; dnsChallenge: false disables that integration, not HTTPS.
• Linode mode uses ROSTER_DNS_PROVIDER=linode and LINODE_API_KEY from the application's secret configuration; a key also selects Linode when no provider is set. With an explicit dnsChallenge object, include module: 'acme-dns-01-cli' to select the wrapper.
• For unattended Linode operation that must fail rather than fall back to manual DNS, set dnsChallenge.dnsApiFallbackToManual: false. Keep other provider choices explicit.
• combineWildcardCerts combines apex/www/wildcard issuance using DNS-01; disableWildcard ignores wildcard sites. Do not enable either as a generic troubleshooting step.
• ensureCertificate(name) loads existing PEMs or issues missing ones; loadCertificate(name) only reads files. Neither means “force renewal.” File-based SNI caches detect certificate changes on supported runtimes.
• In local testing, Bun 1.3.4's node:https serving helper did not invoke SNICallback, including with the previous synchronous resolver. Do not promise SNI certificate reload merely because files changed; Node and Bun require separate runtime verification.
• Request plugins registered with roster.use(fn) are synchronous and run before redirects/dispatch. Return true only after handling the response. Promise returns produce 500.
• The optional createScannerBlocker comes from roster-server/plugins/scanner-blocker.js. Its ban state is per process and in memory. Enable trustProxy only when a trusted proxy overwrites X-Forwarded-For; onBlock does not itself provide shared bans.

Use the consuming application's installed README for the complete options and method signatures. The upstream README is the project reference; prefer documentation matching the installed version.