refactor: move warmup to makePreferredLivekitFoci

src/rtcSessionHelpers.ts

@@ -47,18 +47,47 @@ async function makePreferredLivekitFoci(
     preferredFoci.push(focusInUse);
   }
 
+  // Stop-gap solution for pre-warming the SFU.
+  // This is needed to ensure that the livekit room is created before we try to join the rtc session.
+  // This is because the livekit room creation is done by the auth service and this can be restricted to
+  // only specific users, so we need to ensure that the room is created before we try to send state events.
+  let shouldWarmup = true;
+
   // Prioritize the .well-known/matrix/client, if available, over the configured SFU
   const domain = rtcSession.room.client.getDomain();
   if (domain) {
     // we use AutoDiscovery instead of relying on the MatrixClient having already
     // been fully configured and started
-    const wellKnownFoci = await getFocusListFromWellKnown(domain, livekitAlias);
-    logger.log("Adding livekit focus from well known: ", wellKnownFoci);
-    preferredFoci.push(...wellKnownFoci);
+    const wellKnownFoci = (await AutoDiscovery.getRawClientConfig(domain))?.[
+      FOCI_WK_KEY
+    ];
+    if (Array.isArray(wellKnownFoci)) {
+      const validWellKnownFoci = wellKnownFoci
+        .filter((f) => !!f)
+        .filter(isLivekitFocusConfig)
+        .map((wellKnownFocus) => {
+          logger.log("Adding livekit focus from well known: ", wellKnownFocus);
+          return { ...wellKnownFocus, livekit_alias: livekitAlias };
+        });
+      if (validWellKnownFoci.length > 0) {
+        const toWarmup = validWellKnownFoci[0];
+        await getSFUConfigWithOpenID(rtcSession.room.client, toWarmup);
+        shouldWarmup = false;
+      }
+      preferredFoci.push(...validWellKnownFoci);
+    }
   }
 
-  const focusFormConf = getFocusListFromConfig(livekitAlias);
-  if (focusFormConf) {
+  const urlFromConf = Config.get().livekit?.livekit_service_url;
+  if (urlFromConf) {
+    const focusFormConf: LivekitFocus = {
+      type: "livekit",
+      livekit_service_url: urlFromConf,
+      livekit_alias: livekitAlias,
+    };
+    if (shouldWarmup) {
+      await getSFUConfigWithOpenID(rtcSession.room.client, focusFormConf);
+    }
     logger.log("Adding livekit focus from config: ", focusFormConf);
     preferredFoci.push(focusFormConf);
   }
@@ -76,96 +105,6 @@ async function makePreferredLivekitFoci(
   // if (focusOtherMembers) preferredFoci.push(focusOtherMembers);
 }
 
-async function getFocusListFromWellKnown(
-  domain: string,
-  alias: string,
-): Promise<LivekitFocus[]> {
-  if (domain) {
-    // we use AutoDiscovery instead of relying on the MatrixClient having already
-    // been fully configured and started
-    const wellKnownFoci = (await AutoDiscovery.getRawClientConfig(domain))?.[
-      FOCI_WK_KEY
-    ];
-    if (Array.isArray(wellKnownFoci)) {
-      return wellKnownFoci
-        .filter((f) => !!f)
-        .filter(isLivekitFocusConfig)
-        .map((wellKnownFocus) => {
-          return { ...wellKnownFocus, livekit_alias: alias };
-        });
-    }
-  }
-  return [];
-}
-
-function getFocusListFromConfig(livekitAlias: string): LivekitFocus | null {
-  const urlFromConf = Config.get().livekit?.livekit_service_url;
-  if (urlFromConf) {
-    return {
-      type: "livekit",
-      livekit_service_url: urlFromConf,
-      livekit_alias: livekitAlias,
-    };
-  }
-  return null;
-}
-
-export async function getMyPreferredLivekitFoci(
-  domain: string | null,
-  livekitAlias: string,
-): Promise<LivekitFocus> {
-  if (domain) {
-    // we use AutoDiscovery instead of relying on the MatrixClient having already
-    // been fully configured and started
-    const wellKnownFociList = await getFocusListFromWellKnown(
-      domain,
-      livekitAlias,
-    );
-    if (wellKnownFociList.length > 0) {
-      return wellKnownFociList[0];
-    }
-  }
-
-  const urlFromConf = Config.get().livekit?.livekit_service_url;
-  if (urlFromConf) {
-    return {
-      type: "livekit",
-      livekit_service_url: urlFromConf,
-      livekit_alias: livekitAlias,
-    };
-  }
-  throw new MatrixRTCFocusMissingError(domain ?? "");
-}
-
-// Stop-gap solution for pre-warming the SFU.
-// This is needed to ensure that the livekit room is created before we try to join the rtc session.
-// This is because the livekit room creation is done by the auth service and this can be restricted to
-// only specific users, so we need to ensure that the room is created before we try to join it.
-async function preWarmSFU(
-  rtcSession: MatrixRTCSession,
-  livekitAlias: string,
-): Promise<void> {
-  const client = rtcSession.room.client;
-  // We need to make sure that the livekit room is created before sending the membership event
-  // because other joiners might not be able to join the call if the room does not exist yet.
-  const fociToWarmup = await getMyPreferredLivekitFoci(
-    client.getDomain(),
-    livekitAlias,
-  );
-
-  // Request a token in advance to warm up the livekit room.
-  // Let it throw if it fails, errors will be handled by the ErrorBoundary, if it fails now
-  // it will fail later when we try to join the room.
-  await getSFUConfigWithOpenID(client, fociToWarmup);
-  // For now we don't do anything with the token returned by `getSFUConfigWithOpenID`, it is just to ensure that we
-  // call the `sfu/get` endpoint so that the auth service create the room in advance if it can.
-  // Note: This is not actually checking that the room was created! If the roon creation is
-  // not done by the auth service, the call will fail later when we try to join the room; that case
-  // is a miss-configuration of the auth service, you should be able to create room in your selected SFU.
-  // A solution could be to call the internal `/validate` endpoint to check that the room exists, but this needs
-  // to access livekit internal APIs, so we don't do it for now.
-}
-
 export async function enterRTCSession(
   rtcSession: MatrixRTCSession,
   encryptMedia: boolean,
@@ -184,10 +123,6 @@ export async function enterRTCSession(
   const { features, matrix_rtc_session: matrixRtcSessionConfig } = Config.get();
   const useDeviceSessionMemberEvents =
     features?.feature_use_device_session_member_events;
-
-  // Pre-warm the SFU to ensure that the room is created before anyone tries to join it.
-  await preWarmSFU(rtcSession, livekitAlias);
-
   rtcSession.joinRoomSession(
     await makePreferredLivekitFoci(rtcSession, livekitAlias),
     makeActiveFocus(),