add deleteCall function to properly cleanup Ultravox session

lib/tasks/llm/llms/ultravox_s2s.js

@@ -146,6 +146,23 @@ class TaskLlmUltravox_S2S extends Task {
     return data;
   }
 
+  async deleteCall() {
+    if (!this.callId) return;
+    const baseUrl = 'https://api.ultravox.ai';
+    const url = `${baseUrl}/api/calls/${this.callId}`;
+    try {
+      const {statusCode} = await request(url, {
+        method: 'DELETE',
+        headers: {
+          'X-API-Key': this.apiKey
+        }
+      });
+      this.logger.debug({statusCode, callId: this.callId}, 'Ultravox call deleted');
+    } catch (err) {
+      this.logger.info({err, callId: this.callId}, 'TaskLlmUltravox_S2S:deleteCall - error');
+    }
+  }
+
   _unregisterHandlers(ep) {
     this.removeCustomEventListeners();
     ep.removeAllListeners('dtmf');
@@ -164,6 +181,7 @@ class TaskLlmUltravox_S2S extends Task {
 
     try {
       const data = await this.createCall();
+      this.callId = data.callId;
       const {joinUrl} = data;
       // split the joinUrl into host and path
       const {host, pathname, search} = new URL(joinUrl);
@@ -188,6 +206,8 @@ class TaskLlmUltravox_S2S extends Task {
 
     await this.awaitTaskDone();
 
+    await this.deleteCall();
+
     /* note: the parent llm verb started the span, which is why this is necessary */
     await this.parent.performAction(this.results);
 
@@ -200,6 +220,8 @@ class TaskLlmUltravox_S2S extends Task {
     this._api(cs.ep, [cs.ep.uuid, SessionDelete])
       .catch((err) => this.logger.info({err}, 'TaskLlmUltravox_S2S:kill - error deleting session'));
 
+    this.deleteCall();
+
     this.notifyTaskDone();
   }