File size: 7,088 Bytes
ad32177
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
06e1ad9
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
import gradio as gr
import os
from transformers import (
    GPT2LMHeadModel, GPT2Tokenizer,
    T5ForConditionalGeneration, T5Tokenizer,
    AutoTokenizer, AutoModelForCausalLM
)
import torch

# Configuration for multiple models, can add more by extending MODEL_CONFIGS dict
MODEL_CONFIGS = {
    "gpt2": {
        "type": "causal",
        "model_class": GPT2LMHeadModel,
        "tokenizer_class": GPT2Tokenizer,
        "description": "Original GPT-2, good for creative writing",
        "size": "117M"
    },
    "distilgpt2": {
        "type": "causal",
        "model_class": AutoModelForCausalLM,
        "tokenizer_class": AutoTokenizer,
        "description": "Smaller, faster GPT-2",
        "size": "82M"
    },
    "google/flan-t5-small": {
        "type": "seq2seq",
        "model_class": T5ForConditionalGeneration,
        "tokenizer_class": T5Tokenizer,
        "description": "Instruction-following T5 model",
        "size": "80M"
    },
    "microsoft/DialoGPT-small": {
        "type": "causal",
        "model_class": AutoModelForCausalLM,
        "tokenizer_class": AutoTokenizer,
        "description": "Conversational AI model",
        "size": "117M"
    }
}

# Environment variables for optional authentication and private model access
HF_TOKEN = os.getenv("HF_TOKEN")
API_KEY = os.getenv("API_KEY")
ADMIN_PASSWORD = os.getenv("ADMIN_PASSWORD")

# Global state for caching loaded model and tokenizer
loaded_model_name = None
model = None
tokenizer = None

def load_model_and_tokenizer(model_name):
    global loaded_model_name, model, tokenizer
    if model_name == loaded_model_name and model is not None and tokenizer is not None:
        return model, tokenizer
    
    config = MODEL_CONFIGS[model_name]
    if HF_TOKEN:
        tokenizer = config["tokenizer_class"].from_pretrained(model_name, use_auth_token=HF_TOKEN)
        model = config["model_class"].from_pretrained(model_name, use_auth_token=HF_TOKEN)
    else:
        tokenizer = config["tokenizer_class"].from_pretrained(model_name)
        model = config["model_class"].from_pretrained(model_name)

    # Set pad token for causal models if missing (important for generation padding)
    if config["type"] == "causal" and tokenizer.pad_token is None:
        tokenizer.pad_token = tokenizer.eos_token

    loaded_model_name = model_name
    return model, tokenizer

def authenticate_api_key(key):
    if API_KEY and key != API_KEY:
        return False
    return True

def generate_text(prompt, model_name, max_length, temperature, top_p, top_k, api_key=""):
    if API_KEY and not authenticate_api_key(api_key):
        return "Error: Invalid API key"

    try:
        config = MODEL_CONFIGS[model_name]
        model, tokenizer = load_model_and_tokenizer(model_name)

        if config["type"] == "causal":
            inputs = tokenizer.encode(prompt, return_tensors="pt", max_length=512, truncation=True)
            with torch.no_grad():
                outputs = model.generate(
                    inputs,
                    max_length=min(max_length + inputs.shape[1], 512),
                    temperature=temperature,
                    top_p=top_p,
                    top_k=top_k,
                    do_sample=True,
                    pad_token_id=tokenizer.pad_token_id,
                    num_return_sequences=1
                )
            generated_text = tokenizer.decode(outputs[0], skip_special_tokens=True)
            # Return generated continuation (remove original prompt)
            return generated_text[len(prompt):].strip()

        elif config["type"] == "seq2seq":
            # Add task prefix for certain seq2seq models like flan-t5
            task_prompt = f"Complete this text: {prompt}" if "flan-t5" in model_name.lower() else prompt
            inputs = tokenizer(task_prompt, return_tensors="pt", max_length=512, truncation=True)
            with torch.no_grad():
                outputs = model.generate(
                    **inputs,
                    max_length=max_length,
                    temperature=temperature,
                    top_p=top_p,
                    top_k=top_k,
                    do_sample=True,
                    num_return_sequences=1
                )
            generated_text = tokenizer.decode(outputs[0], skip_special_tokens=True)
            return generated_text.strip()

    except Exception as e:
        return f"Error generating text: {str(e)}"

with gr.Blocks(title="Multi-Model Text Generation Server") as demo:
    gr.Markdown("# Multi-Model Text Generation Server")
    gr.Markdown("Choose a model from the dropdown, enter a text prompt, and generate text.")

    with gr.Row():
        with gr.Column():
            model_selector = gr.Dropdown(
                label="Model",
                choices=list(MODEL_CONFIGS.keys()),
                value="gpt2",
                interactive=True
            )
            prompt_input = gr.Textbox(
                label="Text Prompt",
                placeholder="Enter the text prompt here...",
                lines=4
            )
            max_length_slider = gr.Slider(
                10, 200, 100, 10,
                label="Max Generation Length"
            )
            temperature_slider = gr.Slider(
                0.1, 2.0, 0.7, 0.1,
                label="Temperature"
            )
            top_p_slider = gr.Slider(
                0.1, 1.0, 0.9, 0.05,
                label="Top-p (nucleus sampling)"
            )
            top_k_slider = gr.Slider(
                1, 100, 50, 1,
                label="Top-k sampling"
            )
            if API_KEY:
                api_key_input = gr.Textbox(
                    label="API Key",
                    type="password",
                    placeholder="Enter API Key"
                )
            else:
                api_key_input = gr.Textbox(value="", visible=False)

            generate_btn = gr.Button("Generate Text", variant="primary")

        with gr.Column():
            output_textbox = gr.Textbox(
                label="Generated Text",
                lines=10,
                placeholder="Generated text will appear here..."
            )

    generate_btn.click(
        fn=generate_text,
        inputs=[prompt_input, model_selector, max_length_slider, temperature_slider, top_p_slider, top_k_slider, api_key_input],
        outputs=output_textbox
    )

    gr.Examples(
        examples=[
            ["Once upon a time in a distant galaxy,"],
            ["The future of artificial intelligence is"],
            ["In the heart of the ancient forest,"],
            ["The detective walked into the room and noticed"],
        ],
        inputs=prompt_input
    )

auth_config = ("admin", ADMIN_PASSWORD) if ADMIN_PASSWORD else None

if __name__ == "__main__":
    demo.launch(
        auth=auth_config,
        share=True,        # Required for Spaces if localhost isn't accessible
        server_name="0.0.0.0",
        server_port=7860,
        ssr_mode=False     # Optional: disable server-side rendering to avoid Svelte i18n error
    )