Setup datadog llm observability to trace llm calls

backend/appHandler.ts

@@ -1,3 +1,5 @@
+import './src/tracer';
+
 import 'reflect-metadata';
 import serverlessHttp from 'serverless-http';
 import 'source-map-support/register';

backend/generateStoryTitles.ts

@@ -1,3 +1,4 @@
+import './src/tracer';
 import generateStoryTitlesImpl from './src/cron/generateStoryTitles';
 
 import withSetup from './withSetup';

backend/serverless.yml

@@ -47,6 +47,7 @@ provider:
     OPENAI_SK: ${ssm:/${self:service}-${sls:stage}-openai-sk}
     RAPIDAPI_API_KEY: ${ssm:/${self:service}-${sls:stage}-rapidapi-api-key}
     PRINTFUL_SK: ${ssm:/${self:service}-${sls:stage}-printful-sk}
+    DD_LLMOBS_ML_APP: fourtiesnyc
 plugins:
   - serverless-plugin-conditional-functions
   - serverless-webpack

backend/src/business/ai/AiService.ts

@@ -1,3 +1,4 @@
+import tracer from 'dd-trace';
 import OpenAI from 'openai';
 import createStoryTitlePrompt from './createStoryTitlePrompt';
 
@@ -7,9 +8,14 @@ const openai = new OpenAI({
 });
 
 export async function suggestStoryTitle(storyContent: string): Promise<string> {
-  const response = await openai.chat.completions.create(
-    createStoryTitlePrompt(storyContent)
-  );
+  return tracer.llmobs.trace(
+    { kind: 'task', name: 'story-title-generation' },
+    async () => {
+      const response = await openai.chat.completions.create(
+        createStoryTitlePrompt(storyContent)
+      );
 
-  return response.choices[0].message.content?.trim() ?? '';
+      return response.choices[0].message.content?.trim() ?? '';
+    }
+  );
 }

backend/src/tracer.ts

@@ -0,0 +1,10 @@
+import tracer from 'dd-trace';
+
+tracer.init({
+  llmobs: {
+    mlApp: process.env.DD_LLMOBS_ML_APP,
+    agentlessEnabled: true,
+  },
+});
+
+export default tracer;