api.py

import requests
import numpy as np
import tensorflow as tf
from tensorflow.keras import layers  
import asyncio
from fastapi import FastAPI, Request
from fastapi.responses import StreamingResponse
import sentencepiece as spm
app = FastAPI()    

from fastapi.middleware.cors import CORSMiddleware

origins = [
    "https://insect5386.github.io",
    "https://insect5386.github.io/insect5386"
]

app.add_middleware(
    CORSMiddleware,
    allow_origins=origins,
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)
      
sp = spm.SentencePieceProcessor()      
sp.load("kolig_unigram.model")      
      
pad_id = sp.piece_to_id("<pad>")      
if pad_id == -1: pad_id = 0      
start_id = sp.piece_to_id("<start>")      
if start_id == -1: start_id = 1      
end_id = sp.piece_to_id("<end>")      
if end_id == -1: end_id = 2      
unk_id = sp.piece_to_id("<unk>")      
if unk_id == -1: unk_id = 3      
      
vocab_size = sp.get_piece_size()      
max_len = 100      
      
def text_to_ids(text):      
    return sp.encode(text, out_type=int)      
      
def ids_to_text(ids):      
    return sp.decode(ids)      
    
class RotaryPositionalEmbedding(layers.Layer):      
    def __init__(self, dim):      
        super().__init__()      
        inv_freq = 1.0 / (10000 ** (np.arange(0, dim, 2) / dim))      
        self.inv_freq = tf.constant(inv_freq, dtype=tf.float32)      
      
    def call(self, x):      
        batch, heads, seq_len, depth = tf.unstack(tf.shape(x))      
        t = tf.range(seq_len, dtype=tf.float32)      
        freqs = tf.einsum('i,j->ij', t, self.inv_freq)      
        emb_sin = tf.sin(freqs)      
        emb_cos = tf.cos(freqs)      
        emb_cos = tf.reshape(emb_cos, [1, 1, seq_len, -1])      
        emb_sin = tf.reshape(emb_sin, [1, 1, seq_len, -1])      
        x1 = x[..., ::2]      
        x2 = x[..., 1::2]      
        x_rotated = tf.stack([      
            x1 * emb_cos - x2 * emb_sin,      
            x1 * emb_sin + x2 * emb_cos      
        ], axis=-1)      
        x_rotated = tf.reshape(x_rotated, tf.shape(x))      
        return x_rotated    
    
class SwiGLU(tf.keras.layers.Layer):    
    def __init__(self, d_model, d_ff):    
        super().__init__()    
        self.proj = tf.keras.layers.Dense(d_ff * 2)    
        self.out = tf.keras.layers.Dense(d_model)    
    
    def call(self, x):    
        x_proj = self.proj(x)    
        x_val, x_gate = tf.split(x_proj, 2, axis=-1)    
        return self.out(x_val * tf.nn.silu(x_gate))    
            
class GPTBlock(tf.keras.layers.Layer):    
    def __init__(self, d_model, d_ff, num_heads=8, dropout_rate=0.1, adapter_dim=64):      
        super().__init__()      
        self.ln1 = tf.keras.layers.LayerNormalization(epsilon=1e-5)      
        self.mha = tf.keras.layers.MultiHeadAttention(num_heads=num_heads, key_dim=d_model // num_heads)      
        self.dropout1 = tf.keras.layers.Dropout(dropout_rate)     
        self.adapter_down = tf.keras.layers.Dense(adapter_dim, activation='gelu')     
        self.adapter_up = tf.keras.layers.Dense(d_model)      
      
        self.ln2 = tf.keras.layers.LayerNormalization(epsilon=1e-5)      
        self.ffn = SwiGLU(d_model, d_ff)      
        self.dropout2 = tf.keras.layers.Dropout(dropout_rate)     
        self.rope = RotaryPositionalEmbedding(d_model // num_heads)      
      
    def call(self, x, training=False):      
        x_norm = self.ln1(x)      
        b, s, _ = tf.shape(x_norm)[0], tf.shape(x_norm)[1], tf.shape(x_norm)[2]      
        h = self.mha.num_heads      
        d = x_norm.shape[-1] // h      
      
        qkv = tf.reshape(x_norm, [b, s, h, d])      
        qkv = tf.transpose(qkv, [0, 2, 1, 3])      
        q = self.rope(qkv)      
        k = self.rope(qkv)      
        q = tf.reshape(tf.transpose(q, [0, 2, 1, 3]), [b, s, h * d])      
        k = tf.reshape(tf.transpose(k, [0, 2, 1, 3]), [b, s, h * d])      
      
        attn_out = self.mha(query=q, value=x_norm, key=k, use_causal_mask=True, training=training)      
        attn_out = self.dropout1(attn_out, training=training)      
    
        adapter_out = self.adapter_up(self.adapter_down(attn_out))    
        attn_out = attn_out + adapter_out      
      
        x = x + attn_out      
        ffn_out = self.ffn(self.ln2(x))      
        x = x + self.dropout2(ffn_out, training=training)      
        return x    
    
class InteractGPT(tf.keras.Model):      
    def __init__(self, vocab_size, seq_len, d_model, d_ff, n_layers, num_heads=8, dropout_rate=0.1):      
        super().__init__()      
        self.token_embedding = tf.keras.layers.Embedding(vocab_size, d_model)      
        self.blocks = [GPTBlock(d_model, d_ff, num_heads, dropout_rate) for _ in range(n_layers)]      
        self.ln_f = tf.keras.layers.LayerNormalization(epsilon=1e-5)      
      
    def call(self, x, training=False):      
        x = self.token_embedding(x)      
        for block in self.blocks:      
            x = block(x, training=training)      
        x = self.ln_f(x)      
        logits = tf.matmul(x, self.token_embedding.embeddings, transpose_b=True)      
        return logits      
    
model = InteractGPT(vocab_size=vocab_size, seq_len=max_len, d_model=256, d_ff=1024, n_layers=6)        
      
dummy_input = tf.zeros((1, max_len), dtype=tf.int32)  # 배치1, 시퀀스길이 max_len      
_ = model(dummy_input)  # 모델이 빌드됨      
model.load_weights("InteractGPT.weights.h5")      
print("모델 가중치 로드 완료!")      

def generate_text_top_kp(model, prompt, max_len=100, max_gen=98,
                         temperature=1.0, min_len=20,
                         repetition_penalty=1.1, top_k=40, top_p=0.9):
    model_input = text_to_ids(f"<start> {prompt} <sep>")
    model_input = model_input[:max_len]
    generated = list(model_input)

    for step in range(max_gen):
        pad_len = max(0, max_len - len(generated))
        input_padded = np.pad(generated, (0, pad_len), constant_values=pad_id)
        input_tensor = tf.convert_to_tensor([input_padded])

        logits = model(input_tensor, training=False)
        next_logits = logits[0, len(generated) - 1].numpy()

        # 반복 억제
        for t in set(generated):
            count = generated.count(t)
            next_logits[t] /= (repetition_penalty ** count)

        # 조기 종료 방지
        if len(generated) < min_len:
            next_logits[end_id] -= 5.0
        next_logits[pad_id] -= 10.0

        # 온도 적용
        next_logits = next_logits / temperature
        probs = np.exp(next_logits - np.max(next_logits))
        probs /= probs.sum()

        # Top-K 적용
        top_k = min(top_k, len(probs))
        top_k_idx = np.argsort(-probs)[:top_k]
        top_k_probs = probs[top_k_idx]
        top_k_probs /= top_k_probs.sum()

        # Top-P 필터링
        sorted_idx = np.argsort(-top_k_probs)
        sorted_probs = top_k_probs[sorted_idx]
        cum_probs = np.cumsum(sorted_probs)
        cutoff = np.searchsorted(cum_probs, top_p) + 1

        final_idx = top_k_idx[sorted_idx[:cutoff]]
        final_probs = sorted_probs[:cutoff]
        final_probs /= final_probs.sum()

        sampled = np.random.choice(final_idx, p=final_probs)
        generated.append(int(sampled))

        decoded = sp.decode(generated)
        for t in ["<start>", "<sep>", "<end>"]:
            decoded = decoded.replace(t, "")
        decoded = decoded.strip()

        if len(generated) >= min_len and (sampled == end_id or decoded.endswith(('.', '!', '?'))):
            yield decoded
            break

async def async_generator_wrapper(prompt: str):
    gen = generate_text_top_kp(model, prompt)
    for text_piece in gen:
        yield text_piece
        await asyncio.sleep(0.1)

@app.get("/generate")
async def generate(request: Request):
    prompt = request.query_params.get("prompt", "안녕하세요")
    return StreamingResponse(async_generator_wrapper(prompt), media_type="text/plain")