Upload inference.py (#4)

- Upload inference.py (22da08d63ba35db029b516c1dee3af044e7019bb)


Co-authored-by: GRINDA AI <[email protected]>

inference.py

@@ -0,0 +1,94 @@
+import os
+import json
+import torch
+from vllm import LLM, SamplingParams
+from vllm.utils import random_uuid
+from typing import List, Dict
+
+# Function to format chat messages using Qwen's chat template
+def format_chat(messages: List[Dict[str, str]]) -> str:
+    """
+    Format chat messages using Qwen's chat template
+    """
+    formatted_text = ""
+    for message in messages:
+        role = message["role"]
+        content = message["content"]
+        
+        if role == "system":
+            formatted_text += f"<|im_start|>system\n{content}<|im_end|>\n"
+        elif role == "user":
+            formatted_text += f"<|im_start|>user\n{content}<|im_end|>\n"
+        elif role == "assistant":
+            formatted_text += f"<|im_start|>assistant\n{content}<|im_end|>\n"
+    
+    # Add the final assistant prompt
+    formatted_text += "<|im_start|>assistant\n"
+    
+    return formatted_text
+
+# Model loading function for SageMaker
+def model_fn(model_dir):
+    # Load the quantized model from the model directory
+    model = LLM(
+        model=model_dir,
+        trust_remote_code=True,
+        gpu_memory_utilization=0.9  # Optimal GPU usage
+    )
+    return model
+
+# Custom predict function for SageMaker
+def predict_fn(input_data, model):
+    try:
+        data = json.loads(input_data)
+
+        # Format the prompt using Qwen's chat template
+        messages = data.get("messages", [])
+        formatted_prompt = format_chat(messages)
+
+        # Build sampling parameters (without do_sample to match OpenAI API)
+        sampling_params = SamplingParams(
+            temperature=data.get("temperature", 0.7),
+            top_p=data.get("top_p", 0.9),
+            max_new_tokens=data.get("max_new_tokens", 512),
+            top_k=data.get("top_k", -1),  # Support for top-k sampling
+            repetition_penalty=data.get("repetition_penalty", 1.0),
+            length_penalty=data.get("length_penalty", 1.0),
+            stop_token_ids=data.get("stop_token_ids", None),
+            skip_special_tokens=data.get("skip_special_tokens", True)
+        )
+
+        # Generate output
+        outputs = model.generate(formatted_prompt, sampling_params)
+        generated_text = outputs[0].outputs[0].text
+
+        # Build response
+        response = {
+            "id": f"chatcmpl-{random_uuid()}",
+            "object": "chat.completion",
+            "created": int(torch.cuda.current_timestamp()),
+            "model": "qwen-72b",
+            "choices": [{
+                "index": 0,
+                "message": {
+                    "role": "assistant",
+                    "content": generated_text
+                },
+                "finish_reason": "stop"
+            }],
+            "usage": {
+                "prompt_tokens": len(formatted_prompt),
+                "completion_tokens": len(generated_text),
+                "total_tokens": len(formatted_prompt) + len(generated_text)
+            }
+        }
+        return response
+    except Exception as e:
+        return {"error": str(e), "details": repr(e)}
+
+# Define input and output formats for SageMaker
+def input_fn(serialized_input_data, content_type):
+    return serialized_input_data
+
+def output_fn(prediction_output, accept):
+    return json.dumps(prediction_output)