Merge pull request #586 from devchat-ai/fix_llm_stream_error

fix: Improve LLM stream handling in devchatComplete function

src/contributes/codecomplete/llm.ts

@@ -184,6 +184,7 @@ export async function * ollamaDeepseekComplete(prompt: string) : AsyncGenerator<
 }
 
 
+
 export async function * devchatComplete(prompt: string) : AsyncGenerator<CodeCompletionChunk> {
     const devchatEndpoint = DevChatConfig.getInstance().get("providers.devchat.api_base");
     const llmApiBase = DevChatConfig.getInstance().get("complete_api_base");
@@ -199,24 +200,26 @@ export async function * devchatComplete(prompt: string) : AsyncGenerator<CodeCom
 
     const startTimeLLM = process.hrtime();
 
-	const headers = {
+    const headers = {
-	    'Content-Type': 'application/json'
+        'Content-Type': 'application/json'
-	};
+    };
-	const payload = {
+    const payload = {
-	    model: model,
+        model: model,
-	    prompt: prompt,
+        prompt: prompt,
-	    stream: true,
+        stream: true,
-	    stop: ["<|endoftext|>", "<|EOT|>", "<file_sep>", "\n\n"],
+        stop: ["<|endoftext|>", "<|EOT|>", "<file_sep>", "\n\n"],
-	    temperature: 0.2
+        temperature: 0.2,
-	};
+        max_tokens: 200
+    };
 
-    let idResponse = undefined;
+    // 内部实现的 sleep 函数
+    const sleep = (ms: number) => new Promise(resolve => setTimeout(resolve, ms));
 
     try {
         const response = await fetch(completionApiBase, {
             method: 'POST',
-    		headers,
+            headers,
-    		body: JSON.stringify(payload),
+            body: JSON.stringify(payload),
         });
 
         if (response.ok && response.body) {
@@ -227,8 +230,27 @@ export async function * devchatComplete(prompt: string) : AsyncGenerator<CodeCom
             const durationLLM = endTimeLLM[0] + endTimeLLM[1] / 1e9;
             logger.channel()?.debug(`LLM api post took ${durationLLM} seconds`);
 
-            let hasFirstLine = false;
             let hasFirstChunk = false;
+            let hasFirstLine = false;
+            let buffer = '';
+            const dataRegex = /^data: /m;  // 匹配行首的 "data: "
+
+            // 模拟接收数据的函数
+            async function* simulateStreamReceive(stream: any): AsyncGenerator<Uint8Array> {
+                for await (const chunk of stream) {
+                    const chunkSize = chunk.length;
+                    const numParts = Math.ceil(Math.random() * 3) + 1; // 随机将chunk分成1-4部分
+                    const partSize = Math.ceil(chunkSize / numParts);
+
+                    for (let i = 0; i < chunkSize; i += partSize) {
+                        const part = chunk.slice(i, Math.min(i + partSize, chunkSize));
+                        logger.channel()?.debug(`Simulated receiving part ${i / partSize + 1}/${numParts} of chunk, size: ${part.length} bytes`);
+                        yield part;
+                        await sleep(Math.random() * 100); // 模拟网络延迟，0-100ms
+                    }
+                }
+            }
+
             for await (const chunk of stream) {
                 if (!hasFirstChunk) {
                     hasFirstChunk = true;
@@ -236,33 +258,25 @@ export async function * devchatComplete(prompt: string) : AsyncGenerator<CodeCom
                     const durationFirstChunk = endTimeFirstChunk[0] + endTimeFirstChunk[1] / 1e9;
                     logger.channel()?.debug(`LLM first chunk took ${durationFirstChunk} seconds`);
                 }
-                const chunkDataText = decoder.decode(chunk).trim();
-                // split chunkText by "data: ", for example:
-                // data: 123 data: 456 will split to ["", "data: 123 ", "data: 456"]
-                const chunkTexts = chunkDataText.split("data: ");
-                for (const chunkTextSplit of chunkTexts) {
-                    if (chunkTextSplit.trim().length === 0) {
-                        continue;
-                    }
-                    
-                    const chunkText = "data: " + chunkTextSplit.trim();
-                    
-                    // logger.channel()?.info("receve chunk:", chunkText);
-                    // data: {"id": "cmpl-1713846153", "created": 1713846160.292709, "object": "completion.chunk", "model": "ollama/starcoder2:7b", "choices": [{"index": 0, "finish_reason": "stop", "text": "\n});"}]}
-                    // data: {"id": "cmpl-1713846153", "created": 1713846160.366049, "object": "completion.chunk", "model": "ollama/starcoder2:7b", "choices": [{"index": 0, "finish_reason": "stop", "text": ""}], "usage": {"prompt_tokens": 413, "completion_tokens": 16}}
-                    if (!chunkText.startsWith("data:")) {
-                        // log unexpected data
-                        logger.channel()?.warn("Unexpected data: " + chunkText);
-                        return;
-                    }
 
-                    const jsonData = chunkText.substring(5).trim();
+                const chunkDataText = decoder.decode(chunk);
+                buffer += chunkDataText;
+
+                while (true) {
+                    const match = dataRegex.exec(buffer);
+                    if (!match) break;
+
+                    const dataStart = match.index;
+                    const nextDataStart = buffer.slice(dataStart + 5).search(dataRegex);
+                    const jsonEnd = nextDataStart !== -1 ? dataStart + 5 + nextDataStart : buffer.length;
+                    const jsonData = buffer.substring(dataStart + 5, jsonEnd).trim();
+
                     if (jsonData === "[DONE]") {
                         return;
                     }
 
                     try {
-                        const data = JSON.parse(chunkText.substring(5).trim());
+                        const data = JSON.parse(jsonData);
                         if (!hasFirstLine && data.choices[0].text.indexOf("\n") !== -1) {
                             hasFirstLine = true;
                             const endTimeLine = process.hrtime(startTimeLLM);
@@ -273,9 +287,14 @@ export async function * devchatComplete(prompt: string) : AsyncGenerator<CodeCom
                             text: data.choices[0].text,
                             id: data.id
                         };
-                    } catch (e: any) {
+                        buffer = buffer.slice(jsonEnd);
-                        logger.channel()?.info("receve:", chunkText);
+                    } catch (e) {
-                        logger.channel()?.warn("JSON Parsing Error:", e.message);
+                        // 如果解析失败，可能是因为数据不完整，我们继续到下一个循环
+                        if (nextDataStart === -1) {
+                            // 如果没有下一个 'data:'，保留剩余的buffer
+                            break;
+                        }
+                        buffer = buffer.slice(dataStart + 5 + nextDataStart);
                     }
                 }
             }