feat: Log condensed streaming responses for chat completions

Author: ericc-ch

src/routes/chat-completions/handler.ts

@@ -3,31 +3,74 @@ import type { Context } from "hono"
 import { streamSSE, type SSEMessage } from "hono/streaming"
 
 import type { ChatCompletionsPayload } from "~/services/copilot/chat-completions/types"
+import type { ChatCompletionChunk } from "~/services/copilot/chat-completions/types-streaming"
 
 import { logger } from "~/lib/logger"
 import { chatCompletions } from "~/services/copilot/chat-completions/service"
 import { chatCompletionsStream } from "~/services/copilot/chat-completions/service-streaming"
 
+function createCondensedStreamingResponse(
+  finalChunk: ChatCompletionChunk,
+  collectedContent: string,
+) {
+  return {
+    id: finalChunk.id,
+    model: finalChunk.model,
+    created: finalChunk.created,
+    object: "chat.completion",
+    system_fingerprint: finalChunk.system_fingerprint,
+    usage: finalChunk.usage,
+    choices: [
+      {
+        index: 0,
+        finish_reason: finalChunk.choices[0].finish_reason,
+        message: {
+          role: "assistant",
+          content: collectedContent,
+        },
+        content_filter_results: finalChunk.choices[0].content_filter_results,
+      },
+    ],
+  }
+}
+
 export async function handlerStreaming(c: Context) {
   const payload = await c.req.json<ChatCompletionsPayload>()
 
-  // Log the request
+  // Log the request at the beginning for both streaming and non-streaming cases
   await logger.logRequest("/chat/completions", "POST", payload)
 
   if (payload.stream) {
     const response = await chatCompletionsStream(payload)
 
-    // For streaming responses, we'll log the initial response setup
-    await logger.logResponse("/chat/completions", {
-      type: "stream",
-      timestamp: new Date().toISOString(),
-      model: payload.model,
-    })
+    // For collecting the complete streaming response
+    let collectedContent = ""
+    let finalChunk: ChatCompletionChunk | null = null
 
     return streamSSE(c, async (stream) => {
       for await (const chunk of response) {
+        const data = JSON.parse(chunk.data ?? "{}") as ChatCompletionChunk
+
+        // Keep track of the latest chunk for metadata
+        finalChunk = data
+
+        // Accumulate content from each delta
+        if (data.choices[0].delta.content) {
+          collectedContent += data.choices[0].delta.content
+        }
+
         await stream.writeSSE(chunk as SSEMessage)
       }
+
+      // After streaming completes, log the condensed response
+      if (finalChunk) {
+        const condensedResponse = createCondensedStreamingResponse(
+          finalChunk,
+          collectedContent,
+        )
+
+        await logger.logResponse("/chat/completions", condensedResponse)
+      }
     })
   }
 

src/services/copilot/chat-completions/types-streaming.ts

@@ -51,7 +51,7 @@ interface Usage {
   total_tokens: number
 }
 
-interface ChatCompletionResponse {
+export interface ChatCompletionChunk {
   choices: [Choice]
   created: number
   object: "chat.completion.chunk"
@@ -61,7 +61,3 @@ interface ChatCompletionResponse {
   prompt_filter_results?: Array<PromptFilterResult>
   usage?: Usage | null
 }
-
-export interface ChatCompletionsChunk {
-  data: ChatCompletionResponse
-}