local-llm-server/llm_server/routes/v1/generate_stream.py

import json
import time
import traceback

from flask import request

from ..helpers.client import format_sillytavern_err
from ..helpers.http import validate_json
from ..ooba_request_handler import OobaRequestHandler
from ... import opts
from ...database.database import increment_token_uses, log_prompt
from ...llm.generator import generator
from ...llm.vllm import tokenize
from ...stream import sock


# TODO: have workers process streaming requests
# TODO: make sure to log the token as well (seems to be missing in the DB right now)

@sock.route('/api/v1/stream')
def stream(ws):
    if not opts.enable_streaming:
        # TODO: return a formatted ST error message
        return 'disabled', 401

    message_num = 0
    while ws.connected:
        message = ws.receive()
        request_valid_json, request_json_body = validate_json(message)
        if not request_valid_json or not request_json_body.get('prompt'):
            ws.send(json.dumps({
                'event': 'text_stream',
                'message_num': message_num,
                'text': 'Invalid JSON'
            }))
            message_num += 1
        else:
            if opts.mode != 'vllm':
                # TODO: implement other backends
                raise NotImplementedError

            handler = OobaRequestHandler(request, request_json_body)
            token = request_json_body.get('X-API-KEY')
            generated_text = ''
            input_prompt = None
            response_status_code = 0
            start_time = time.time()
            request_valid, invalid_response = handler.validate_request()
            if not request_valid:
                ws.send(json.dumps({
                    'event': 'text_stream',
                    'message_num': message_num,
                    'text': invalid_response
                }))
            else:
                input_prompt = request_json_body['prompt']
                msg_to_backend = {
                    **handler.parameters,
                    'prompt': input_prompt,
                    'stream': True,
                }

                try:
                    response = generator(msg_to_backend)

                    # Be extra careful when getting attributes from the response object
                    try:
                        response_status_code = response.status_code
                    except:
                        response_status_code = 0

                    partial_response = b''

                    for chunk in response.iter_content(chunk_size=1):
                        partial_response += chunk
                        if partial_response.endswith(b'\x00'):
                            json_str = partial_response[:-1].decode()  # Remove the null character and decode the byte string to a string
                            json_obj = json.loads(json_str)
                            try:
                                new = json_obj['text'][0].split(input_prompt + generated_text)[1]
                            except IndexError:
                                # ????
                                continue

                            ws.send(json.dumps({
                                'event': 'text_stream',
                                'message_num': message_num,
                                'text': new
                            }))
                            message_num += 1

                            generated_text = generated_text + new
                            partial_response = b''  # Reset the partial response

                        # If there is no more data, break the loop
                        if not chunk:
                            break

                    response.close()

                    end_time = time.time()
                    elapsed_time = end_time - start_time
                    generated_tokens = tokenize(generated_text)
                    log_prompt(handler.client_ip, handler.token, input_prompt, generated_text, elapsed_time, handler.parameters, dict(request.headers), response_status_code, request.url, response_tokens=generated_tokens)
                except:
                    generated_text = generated_text + '\n\n' + format_sillytavern_err('Encountered error while streaming.', 'error')
                    generated_tokens = tokenize(generated_text)
                    traceback.print_exc()
                    ws.send(json.dumps({
                        'event': 'text_stream',
                        'message_num': message_num,
                        'text': generated_text
                    }))
                    log_prompt(handler.client_ip, handler.token, input_prompt, generated_text, None, handler.parameters, dict(request.headers), response_status_code, request.url, response_tokens=generated_tokens)

        ws.send(json.dumps({
            'event': 'stream_end',
            'message_num': message_num
        }))