feat: include jambonz and drachtio versions in X-Jambonz-Discover response

- jambonzVersion is read from the schema_version table via the existing
  db-helpers pool (now exposed on srf.locals); a DB error yields null
  rather than failing discovery
- drachtioVersion is captured from the drachtio connect handshake and
  stored on srf.locals
- README example updated

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

README.md

@@ -40,13 +40,15 @@ An OPTIONS request carrying the header `X-Jambonz-Discover: true` (from any IP,
 
 ```json
 {
+  "jambonzVersion": "v11.1.4",
+  "drachtioVersion": "v0.9.3",
   "featureServers": ["10.0.0.10:5060"],
   "sipServers": ["1.2.3.4"],
   "rtpServers": ["10.0.0.20"]
 }
 ```
 
-`featureServers`, `sipServers` and `rtpServers` are the IPs (feature servers include the port) of the active feature servers, SIP servers and RTP servers respectively. When `JAMBONES_SERVER_CONTROL` is not set, the discovery header is ignored and OPTIONS behaves as normal.
+`jambonzVersion` is read from the `schema_version` table in the database and `drachtioVersion` is the version reported by the drachtio server on connect; either is `null` if it could not be determined. `featureServers`, `sipServers` and `rtpServers` are the IPs (feature servers include the port) of the active feature servers, SIP servers and RTP servers respectively. When `JAMBONES_SERVER_CONTROL` is not set, the discovery header is ignored and OPTIONS behaves as normal.
 
 ## CLI Management
 

app.js

@@ -51,6 +51,7 @@ const Registrar = require('@jambonz/mw-registrar');
 const digestChallenge = require('@jambonz/digest-utils');
 const debug = require('debug')('jambonz:sbc-registrar');
 const {
+  pool,
   lookupAuthHook,
   lookupAllVoipCarriers,
   lookupSipGatewaysByCarrier,
@@ -111,6 +112,7 @@ srf.locals = {
   ...srf.locals,
   logger,
   stats,
+  pool,
   addToSet, removeFromSet, isMemberOfSet, retrieveSet,
   registrar: new Registrar(logger, client),
   dbHelpers: {
@@ -155,7 +157,8 @@ srf.on('connect', (err, hp, version, localHostports) => {
   // drachtio-srf re-emits 'connect' on every reconnect; distinguish a reconnect from first connect
   const isReconnect = drachtioConnected;
   drachtioConnected = true;
-  logger.info(`connected to drachtio listening on ${hp}, local hostports: ${localHostports}`);
+  logger.info(`connected to drachtio ${version} listening on ${hp}, local hostports: ${localHostports}`);
+  srf.locals.drachtioVersion = version || null;
 
   if (localHostports) {
     const locals = localHostports.split(',');

lib/server-control/index.js

@@ -35,22 +35,44 @@ const isDiscoverRequest = (req) => {
 };
 
 /**
- * Read the current cluster topology from redis: the IPs of the feature
- * servers, SIP servers and RTP servers.
- * @param {object} srf - drachtio srf instance (uses srf.locals.retrieveSet)
- * @returns {Promise<{featureServers: string[], sipServers: string[], rtpServers: string[]}>}
+ * Read the installed jambonz version from the schema_version table.
+ * A failure here must not fail discovery, so it resolves to null on any error.
+ * @param {object} pool - mysql connection pool (may be undefined in tests)
+ * @returns {Promise<string|null>}
+ */
+const _lookupJambonzVersion = (pool) => new Promise((resolve) => {
+  if (!pool) return resolve(null);
+  pool.query('SELECT version FROM schema_version', (err, results) => {
+    if (err) {
+      debug({err}, 'failed reading schema_version');
+      return resolve(null);
+    }
+    resolve(results && results.length ? results[0].version : null);
+  });
+});
+
+/**
+ * Read the current cluster topology from redis (the IPs of the feature
+ * servers, SIP servers and RTP servers) plus the jambonz version
+ * (schema_version table) and the drachtio server version (captured on connect).
+ * @param {object} srf - drachtio srf instance (uses srf.locals.retrieveSet, srf.locals.pool)
+ * @returns {Promise<{jambonzVersion: string|null, drachtioVersion: string|null,
+ *   featureServers: string[], sipServers: string[], rtpServers: string[]}>}
  */
 const discoverServers = async(srf) => {
-  const { retrieveSet } = srf.locals;
+  const { retrieveSet, pool, drachtioVersion } = srf.locals;
   const { featureServers, sipServers, rtpServers } = _setNames();
 
-  const [fs, sip, rtp] = await Promise.all([
+  const [fs, sip, rtp, jambonzVersion] = await Promise.all([
     retrieveSet(featureServers),
     retrieveSet(sipServers),
-    retrieveSet(rtpServers)
+    retrieveSet(rtpServers),
+    _lookupJambonzVersion(pool)
   ]);
 
   const topology = {
+    jambonzVersion,
+    drachtioVersion: drachtioVersion || null,
     featureServers: fs || [],
     sipServers: sip || [],
     rtpServers: rtp || []