Spaces:
Running
on
Zero
Running
on
Zero
File size: 3,976 Bytes
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"""
File: vlm.py
Description: Vision language model utility functions.
Author: Didier Guillevic
Date: 2025-03-16
"""
import spaces
from transformers import AutoProcessor, Gemma3ForConditionalGeneration
from transformers import TextIteratorStreamer
from threading import Thread
import torch
#
# Load the model: google/gemma-3-4b-it
#
device = 'cuda' if torch.cuda.is_available() else 'cpu'
model_id = "google/gemma-3-4b-it"
processor = AutoProcessor.from_pretrained(model_id, use_fast=True, padding_side="left")
model = Gemma3ForConditionalGeneration.from_pretrained(
model_id,
torch_dtype=torch.bfloat16
).to(device).eval()
#
# Build messages
#
def build_messages(message: dict, history: list[tuple]):
"""Build messages given message & history from a **multimodal** chat interface.
Args:
message: dictionary with keys: 'text', 'files'
history: list of tuples with (message, response)
Returns:
list of messages (to be sent to the model)
"""
# Get the user's text and list of images
user_text = message.get("text", "")
user_images = message.get("files", []) # List of images
# Build the message list including history
messages = []
combined_user_input = [] #Combine images and text if found in same turn.
for user_turn, bot_turn in history:
if isinstance(user_turn, tuple): # Image input
image_content = [{"type": "image", "url": image_url} for image_url in user_turn]
combined_user_input.extend(image_content)
elif isinstance(user_turn, str): #Text input
combined_user_input.append({"type":"text", "text": user_turn})
if combined_user_input and bot_turn:
messages.append({'role': 'user', 'content': combined_user_input})
messages.append({'role': 'assistant', 'content': [{"type": "text", "text": bot_turn}]})
combined_user_input = [] #reset the combined user input.
# Build the user message's content from the provided message
user_content = []
if user_text:
user_content.append({"type": "text", "text": user_text})
for image in user_images:
user_content.append({"type": "image", "url": image})
messages.append({'role': 'user', 'content': user_content})
return messages
#
# Streaming response
#
@spaces.GPU
@torch.inference_mode()
def stream_response(messages: list[dict]):
"""Stream the model's response to the chat interface.
Args:
messages: list of messages to send to the model
"""
# Generate model's response
inputs = processor.apply_chat_template(
messages, add_generation_prompt=True, tokenize=True,
return_dict=True, return_tensors="pt"
).to(model.device, dtype=torch.bfloat16)
streamer = TextIteratorStreamer(
processor, skip_prompt=True, skip_special_tokens=True)
generation_kwargs = dict(
inputs,
streamer=streamer,
max_new_tokens=2_048,
do_sample=False
)
thread = Thread(target=model.generate, kwargs=generation_kwargs)
thread.start()
partial_message = ""
for new_text in streamer:
partial_message += new_text
yield partial_message
#
# Response (non-streaming)
#
@spaces.GPU
@torch.inference_mode()
def get_response(messages: list[dict]):
"""Get the model's response.
Args:
messages: list of messages to send to the model
"""
# Generate model's response
inputs = processor.apply_chat_template(
messages, add_generation_prompt=True, tokenize=True,
return_dict=True, return_tensors="pt"
).to(model.device, dtype=torch.bfloat16)
input_len = inputs["input_ids"].shape[-1]
with torch.inference_mode():
generation = model.generate(**inputs, max_new_tokens=2_048, do_sample=False)
generation = generation[0][input_len:]
decoded = processor.decode(generation, skip_special_tokens=True)
return decoded
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