Any idea why a stream randomly fails with Unexpected end of JSON input?

[sneko]

Hi,

I'm using MistralAI with chain.stream(...) and randomly I get:

SyntaxError: Unexpected end of JSON input
    at JSON.parse (<anonymous>)
    at MistralClient.chatStream (project/node_modules/@mistralai/mistralai/src/client.js:184:24)
    at chatStream.next (<anonymous>)
    at ChatMistralAI._streamResponseChunks (project/node_modules/@langchain/mistralai/dist/chat_models.js:238:26)
    at _streamResponseChunks.next (<anonymous>)
    at ChatMistralAI._streamIterator (project/node_modules/@langchain/core/dist/language_models/chat_models.js:78:34)
    at _streamIterator.next (<anonymous>)
    at ChatMistralAI.transform (project/node_modules/@langchain/core/dist/runnables/base.js:335:21)
    at transform.next (<anonymous>)
    at wrapInputForTracing (project/node_modules/@langchain/core/dist/runnables/base.js:229:30)
    at wrapInputForTracing.next (<anonymous>)
    at AsyncGeneratorWithSetup.next (project/node_modules/@langchain/core/dist/utils/stream.js:206:31)
    at StringOutputParser._transform (project/node_modules/@langchain/core/dist/output_parsers/transform.js:10:26)
    at _transform.next (<anonymous>)
    at StringOutputParser._transformStreamWithConfig

It comes from the library itself, it's not one of my JSON.parse. I think my internet connection is stable enough... Any of you had this?

Thank you,

[dosubot[bot]]

🤖

Hey @sneko, nice to see you back here! Hope everything else has been going smoothly for you.

The error SyntaxError: Unexpected end of JSON input typically occurs when JSON.parse() is called with an empty string or a string that does not represent a valid JSON object. In your case, it seems like the MistralClient.chatStream function is trying to parse an empty string or invalid JSON, which is causing the error.

This could be due to a few reasons:

1. Network instability: Even if your internet connection is generally stable, temporary network glitches can cause incomplete data to be received, leading to this error.

2. Server-side issues: If the server is not sending complete JSON data for some reason, this error can occur. This could be due to a bug in the server code or temporary server-side issues.

3. Bugs in the MistralClient.chatStream function: If there's a bug in the MistralClient.chatStream function that's causing it to incorrectly handle the data received from the server, this error can occur.

To debug this issue, you could add error handling code in the MistralClient.chatStream function to log the data received from the server before it's parsed. This would help you determine whether the issue is due to network instability, server-side issues, or a bug in the MistralClient.chatStream function.

Here's an example of how you could modify the MistralClient.chatStream function to log the data:

MistralClient.prototype.chatStream = async function (input) {
  // ... existing code ...

  try {
    const response = await this._sendRequest(input);
    console.log('Response received:', response);
    const parsedResponse = JSON.parse(response);
    // ... existing code ...
  } catch (error) {
    console.error('Error parsing response:', error);
  }

  // ... existing code ...
};

Please note that this is just an example and the actual code might be different depending on the implementation of the MistralClient.chatStream function.

If you're still facing this issue after trying these steps, please provide more details about your usage of the MistralClient.chatStream function, including the exact input you're providing and the full error stack trace. This would help in further debugging the issue.

For more information about the SyntaxError: Unexpected end of JSON input error, you can refer to this StackOverflow thread.

For more information about the MistralClient.chatStream function, you can refer to the MistralAI documentation.

Sources

• examples/src/guides/deployment/stream_error_handling.ts
• examples/src/models/chat/chat_stream_mistralai.ts

About Dosu

This response is meant to be useful and save you time. It is not meant to be a precise solution, but rather a starting point for your own research.

Help me be more useful! Please leave a 👍 if this is helpful and 👎 if it is irrelevant.

If you want to continue the conversation, start your reply with @dosu-bot.