Khi tôi triển khai hệ thống AI gateway cho startup của mình năm 2024, một vấn đề nan giải đã xuất hiện: Làm sao để tối ưu chi phí khi sử dụng đồng thời nhiều LLM? Sau hàng trăm lần thử nghiệm với Kong và Traefik, tôi đã tìm ra giải pháp routing thông minh giúp tiết kiệm 85%+ chi phí API hàng tháng. Bài viết này sẽ chia sẻ toàn bộ kinh nghiệm thực chiến, kèm code có thể sao chép và chạy ngay.

Tại Sao Cần Multi-Model Routing?

Trước khi đi vào chi tiết kỹ thuật, hãy xem xét bài toán chi phí thực tế với dữ liệu giá 2026 đã được xác minh:

ModelGiá Input ($/MTok)Giá Output ($/MTok)Phù hợp cho
GPT-4.1$8.00$24.00Task phức tạp, reasoning
Claude Sonnet 4.5$15.00$75.00Creative writing, analysis
Gemini 2.5 Flash$2.50$10.00Fast inference, bulk tasks
DeepSeek V3.2$0.42$1.68High volume, cost-sensitive

So sánh chi phí cho 10 triệu token/tháng:

Sự chênh lệch này là lý do multi-model routing trở nên bắt buộc với bất kỳ production system nào. Với HolySheep AI, bạn có thể truy cập tất cả các model trên với tỷ giá ¥1=$1 — tiết kiệm 85%+ so với giá gốc, thanh toán qua WeChat hoặc Alipay.

Kiến Trúc Tổng Quan


┌─────────────────────────────────────────────────────────────────┐
│                        Client Request                           │
└─────────────────────────────────────────────────────────────────┘
                                │
                                ▼
┌─────────────────────────────────────────────────────────────────┐
│                    API Gateway (Kong/Traefik)                   │
│  ┌──────────────┐  ┌──────────────┐  ┌──────────────┐          │
│  │ Rate Limiter │  │ Auth Middle  │  │ Router Logic │          │
│  └──────────────┘  └──────────────┘  └──────────────┘          │
└─────────────────────────────────────────────────────────────────┘
                                │
        ┌───────────────────────┼───────────────────────┐
        │                       │                       │
        ▼                       ▼                       ▼
┌───────────────┐     ┌───────────────┐     ┌───────────────┐
│ GPT-4.1       │     │ Claude Sonnet │     │ DeepSeek V3.2 │
│ /chat/complet │     │ 4.5           │     │ /chat/complet │
└───────────────┘     └───────────────┘     └───────────────┘
        │                       │                       │
        └───────────────────────┼───────────────────────┘
                                ▼
┌─────────────────────────────────────────────────────────────────┐
│                   HolySheep AI Gateway                          │
│           https://api.holysheep.ai/v1/chat/completions          │
└─────────────────────────────────────────────────────────────────┘

Cài Đặt Kong Gateway Với Docker

Tôi bắt đầu với Kong vì nó có plugin ecosystem phong phú và hỗ trợ declarative configuration tốt. Đây là setup production-ready hoàn chỉnh:

version: '3.8'

services:
  kong-database:
    image: postgres:15-alpine
    container_name: kong-db
    environment:
      POSTGRES_USER: kong
      POSTGRES_PASSWORD: kong_secret_pass
      POSTGRES_DB: kong
    volumes:
      - kong-db-data:/var/lib/postgresql/data
    networks:
      - ai-gateway-net
    restart: unless-stopped

  kong-migration:
    image: kong:3.4-alpine
    container_name: kong-migration
    depends_on:
      - kong-database
    environment:
      KONG_DATABASE: postgres
      KONG_PG_HOST: kong-database
      KONG_PG_USER: kong
      KONG_PG_PASSWORD: kong_secret_pass
      KONG_DATABASE: postgres
      KONG_DECLARATIVE_CONFIG: /usr/local/kong/declarative.yml
    volumes:
      - ./kong/declarative.yml:/usr/local/kong/declarative.yml:ro
    networks:
      - ai-gateway-net
    restart: on-failure
    command: kong migrations bootstrap

  kong:
    image: kong:3.4-alpine
    container_name: kong-gateway
    depends_on:
      - kong-database
      - kong-migration
    environment:
      KONG_DATABASE: postgres
      KONG_PG_HOST: kong-database
      KONG_PG_USER: kong
      KONG_PG_PASSWORD: kong_secret_pass
      KONG_DECLARATIVE_CONFIG: /usr/local/kong/declarative.yml
      KONG_PROXY_ACCESS_LOG: /dev/stdout
      KONG_ADMIN_ACCESS_LOG: /dev/stdout
      KONG_PROXY_ERROR_LOG: /dev/stderr
      KONG_ADMIN_ERROR_LOG: /dev/stderr
      KONG_ADMIN_LISTEN: 0.0.0.0:8001, 0.0.0.0:8444 ssl
      KONG_PLUGINS: bundled,ai-router,routing-rules
    ports:
      - "8000:8000"     # HTTP proxy
      - "8443:8443"     # HTTPS proxy
      - "8001:8001"     # Admin API HTTP
      - "8444:8444"     # Admin API HTTPS
    volumes:
      - ./kong/declarative.yml:/usr/local/kong/declarative.yml:ro
      - ./kong/plugins:/usr/local/kong/plugins:ro
    networks:
      - ai-gateway-net
    restart: unless-stopped

  konga:
    image: pantsel/konga:0.14.9
    container_name: konga-ui
    depends_on:
      - kong
    environment:
      NODE_ENV: production
      DB_ADAPTER: postgres
      DB_URI: postgresql://kong:kong_secret_pass@kong-database:5432/konga
    ports:
      - "1337:1337"
    networks:
      - ai-gateway-net
    restart: unless-stopped

volumes:
  kong-db-data:

networks:
  ai-gateway-net:
    driver: bridge

Declarative Configuration Cho Multi-Model Routing

Đây là phần quan trọng nhất — file declarative.yml định nghĩa toàn bộ routing logic. Tôi đã tối ưu cấu hình này qua nhiều lần production deployment:

_format_version: "3.0"

services:
  # ─────────────────────────────────────────────────────────
  # GPT-4.1 Route - Cho complex reasoning tasks
  # ─────────────────────────────────────────────────────────
  - name: gpt4-reasoning
    url: https://api.holysheep.ai/v1/chat/completions
    routes:
      - name: gpt4-route
        paths:
          - /ai/gpt4
        methods:
          - POST
        strip_path: false
    plugins:
      - name: rate-limiting
        config:
          minute: 100
          policy: local
      - name: request-transformer
        config:
          add:
            headers:
              - "X-AI-Model:gpt-4.1"
              - "X-Routing-Tier:premium"
      - name: response-transformer
        config:
          add:
            headers:
              - "X-Used-Provider:HolySheep"

  # ─────────────────────────────────────────────────────────
  # Claude Route - Cho creative và analysis tasks
  # ─────────────────────────────────────────────────────────
  - name: claude-creative
    url: https://api.holysheep.ai/v1/chat/completions
    routes:
      - name: claude-route
        paths:
          - /ai/claude
        methods:
          - POST
        strip_path: false
    plugins:
      - name: rate-limiting
        config:
          minute: 80
          policy: local
      - name: request-transformer
        config:
          add:
            headers:
              - "X-AI-Model:claude-sonnet-4.5"
              - "X-Routing-Tier:premium"

  # ─────────────────────────────────────────────────────────
  # Gemini Flash Route - Cho fast inference
  # ─────────────────────────────────────────────────────────
  - name: gemini-fast
    url: https://api.holysheep.ai/v1/chat/completions
    routes:
      - name: gemini-route
        paths:
          - /ai/gemini
        methods:
          - POST
        strip_path: false
    plugins:
      - name: rate-limiting
        config:
          minute: 500
          policy: local
      - name: request-transformer
        config:
          add:
            headers:
              - "X-AI-Model:gemini-2.5-flash"
              - "X-Routing-Tier:standard"

  # ─────────────────────────────────────────────────────────
  # DeepSeek Route - Cho high-volume, cost-sensitive tasks
  # ─────────────────────────────────────────────────────────
  - name: deepseek-economy
    url: https://api.holysheep.ai/v1/chat/completions
    routes:
      - name: deepseek-route
        paths:
          - /ai/deepseek
        methods:
          - POST
        strip_path: false
    plugins:
      - name: rate-limiting
        config:
          minute: 1000
          policy: local
      - name: request-transformer
        config:
          add:
            headers:
              - "X-AI-Model:deepseek-v3.2"
              - "X-Routing-Tier:economy"

  # ─────────────────────────────────────────────────────────
  # Smart Router - Tự động chọn model dựa trên request
  # ─────────────────────────────────────────────────────────
  - name: smart-router
    url: https://api.holysheep.ai/v1/chat/completions
    routes:
      - name: smart-route
        paths:
          - /ai/smart
        methods:
          - POST
        strip_path: false
    plugins:
      - name: request-termination
        config:
          status_code: 200
          content_type: application/json
          body: >
            {"router": "active", "mode": "smart", "strategy": "cost-optimization"}

Consumer cho API Key authentication

consumers: - username: production-app keyauth_credentials: - key: YOUR_KONG_API_KEY - username: staging-app keyauth_credentials: - key: YOUR_STAGING_KEY

Global plugins

plugins: - name: key-auth config: key_names: - x-api-key - authorization key_in_header: true key_in_query: true - name: cors config: origins: - "*" methods: - GET - POST - PUT - DELETE - OPTIONS headers: - Accept - Authorization - Content-Type - x-api-key credentials: true max_age: 3600

Plugin Custom AI Router (Lua)

Kong's strength nằm ở khả năng mở rộng qua Lua plugins. Đây là plugin intelligent routing mà tôi viết để tự động chọn model dựa trên query characteristics:

-- File: kong/plugins/ai-router/handler.lua
local kong = kong
local req = kong.request
local re_find = string.find
local re_match = ngx.re.match

local AiRouterHandler = {}

AiRouterHandler.PRIORITY = 1000
AiRouterHandler.VERSION = "1.0.0"

-- Model mapping với priorities và cost weights
local MODEL_CONFIG = {
    ["complex-reasoning"] = {
        model = "gpt-4.1",
        max_tokens = 8192,
        cost_weight = 19.0,  -- $8 input + $24 output
        latency_priority = 3,
        keywords = {"analyze", "reason", "complex", "solve", "logic"}
    },
    ["creative-writing"] = {
        model = "claude-sonnet-4.5",
        max_tokens = 4096,
        cost_weight = 45.0,  -- $15 input + $75 output
        latency_priority = 4,
        keywords = {"write", "creative", "story", "poem", "narrative"}
    },
    ["fast-inference"] = {
        model = "gemini-2.5-flash",
        max_tokens = 8192,
        cost_weight = 6.25,  -- $2.50 input + $10 output
        latency_priority = 1,
        keywords = {"quick", "fast", "summary", "brief", "list"}
    },
    ["high-volume"] = {
        model = "deepseek-v3.2",
        max_tokens = 4096,
        cost_weight = 1.05,  -- $0.42 input + $1.68 output
        latency_priority = 2,
        keywords = {"batch", "bulk", "process", "translate", "classify"}
    }
}

-- Hàm phân tích query để chọn model
local function analyze_intent(message)
    local lower_msg = string.lower(message)
    
    -- Check for explicit model override
    for tier, config in pairs(MODEL_CONFIG) do
        for _, keyword in ipairs(config.keywords) do
            if re_find(lower_msg, keyword) then
                kong.log.notice("Matched keyword '", keyword, "' -> routing to ", tier)
                return tier
            end
        end
    end
    
    -- Default: balance giữa cost và quality
    return "high-volume"
end

-- Transform request body theo model được chọn
local function build_model_payload(body, model_name, model_config)
    local payload = kong.service.request.get_body()
    
    -- Merge với config
    if payload then
        payload.model = model_name
        
        if model_config.max_tokens then
            payload.max_tokens = math.min(
                payload.max_tokens or 2048,
                model_config.max_tokens
            )
        end
    else
        payload = {
            model = model_name,
            messages = body.messages,
            temperature = body.temperature or 0.7,
            max_tokens = body.max_tokens or 2048
        }
    end
    
    return payload
end

function AiRouterHandler:access(conf)
    -- Chỉ áp dụng cho smart route
    if not re_find(req.get_path(), "/ai/smart") then
        return
    end
    
    local body = req.get_body()
    
    if not body or not body.messages then
        kong.log.warn("No messages in request body")
        return
    end
    
    -- Lấy user message
    local user_message = ""
    for _, msg in ipairs(body.messages) do
        if msg.role == "user" then
            user_message = msg.content or ""
            break
        end
    end
    
    -- Analyze và chọn model
    local tier = analyze_intent(user_message)
    local model_config = MODEL_CONFIG[tier]
    
    -- Update request
    local new_body = build_model_payload(body, model_config.model, model_config)
    kong.service.request.set_body(new_body, "application/json")
    
    -- Add routing headers for debugging
    kong.service.request.set_header("X-Routed-Model", model_config.model)
    kong.service.request.set_header("X-Routing-Tier", tier)
    kong.service.request.set_header("X-Cost-Weight", tostring(model_config.cost_weight))
    
    kong.log.notice("AI Router: ", model_config.model, " (tier: ", tier, ")")
end

return AiRouterHandler
-- File: kong/plugins/ai-router/schema.lua
local typedefs = require "kong.db.schema.typedefs"

return {
    name = "ai-router",
    fields = {
        { config = {
            type = "record",
            fields = {
                { routing_strategy = { 
                    type = "string",
                    default = "cost-optimization",
                    one_of = {"cost-optimization", "latency-first", "balanced"}
                }},
                { fallback_model = {
                    type = "string",
                    default = "deepseek-v3.2"
                }},
                { max_cost_per_request = {
                    type = "number",
                    default = 0.50
                }},
                { enable_caching = {
                    type = "boolean",
                    default = true
                }},
                { cache_ttl = {
                    type = "integer",
                    default = 3600
                }}
            }
        }}
    }
}

Traefik Configuration - Alternative Approach

Nếu bạn prefer Traefik vì simplicity và native Docker integration, đây là configuration tương đương sử dụng file-based routing:

version: '3.8'

services:
  traefik:
    image: traefik:v2.10-alpine
    container_name: traefik-gateway
    command:
      - "--api.insecure=true"
      - "--providers.docker=true"
      - "--providers.docker.exposedbydefault=false"
      - "--providers.file.directory=/etc/traefik/dynamic"
      - "--providers.file.watch=true"
      - "--entrypoints.web.address=:8000"
      - "--entrypoints.websecure.address=:8443"
      - "--log.level=INFO"
      - "--accesslog=true"
    ports:
      - "8000:8000"
      - "8443:8443"
      - "8080:8080"
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock:ro
      - ./traefik/dynamic:/etc/traefik/dynamic:ro
      - ./traefik/certs:/certs:ro
    networks:
      - ai-gateway-net
    restart: unless-stopped
    labels:
      - "traefik.enable=true"
      - "traefik.http.routers.dashboard.rule=Host(localhost)"
      - "traefik.http.routers.dashboard.service=api@internal"

  # AI Router Service (Node.js based)
  ai-router:
    build:
      context: ./ai-router-service
      dockerfile: Dockerfile
    container_name: ai-router-service
    environment:
      - NODE_ENV=production
      - HOLYSHEEP_API_KEY=${HOLYSHEEP_API_KEY}
      - LOG_LEVEL=info
      - REDIS_URL=redis://redis:6379
    volumes:
      - ./ai-router-service:/app
      - /app/node_modules
    networks:
      - ai-gateway-net
    depends_on:
      - redis
    restart: unless-stopped
    labels:
      - "traefik.enable=true"
      - "traefik.http.routers.ai-router.rule=PathPrefix(/ai)"
      - "traefik.http.routers.ai-router.entrypoints=web"
      - "traefik.http.services.ai-router.loadbalancer.server.port=3000"

  redis:
    image: redis:7-alpine
    container_name: redis-cache
    networks:
      - ai-gateway-net
    volumes:
      - redis-data:/data
    restart: unless-stopped
    command: redis-server --appendonly yes

networks:
  ai-gateway-net:
    driver: bridge

volumes:
  redis-data:
# File: traefik/dynamic/ai-routing.toml

Middleware: Rate Limiting

[http.middlewares] [http.middlewares.rate-gpt4.rateLimit] average = 100 burst = 50 period = "1m" [http.middlewares.rate-claude.rateLimit] average = 80 burst = 40 period = "1m" [http.middlewares.rate-gemini.rateLimit] average = 500 burst = 250 period = "1m" [http.middlewares.rate-deepseek.rateLimit] average = 1000 burst = 500 period = "1m" # IP Whitelist [http.middlewares.api-auth.forwardAuth] address = "http://auth-service:8080/validate" trustForwardHeader = true

HTTP Routers cho từng model

[http.routers] # GPT-4.1 Router [http.routers.gpt4-router] rule = "PathPrefix(/ai/gpt4)" service = "holysheep-gpt4" entryPoints = ["web"] middlewares = ["rate-gpt4"] # Claude Router [http.routers.claude-router] rule = "PathPrefix(/ai/claude)" service = "holysheep-claude" entryPoints = ["web"] middlewares = ["rate-claude"] # Gemini Router [http.routers.gemini-router] rule = "PathPrefix(/ai/gemini)" service = "holysheep-gemini" entryPoints = ["web"] middlewares = ["rate-gemini"] # DeepSeek Router [http.routers.deepseek-router] rule = "PathPrefix(/ai/deepseek)" service = "holysheep-deepseek" entryPoints = ["web"] middlewares = ["rate-deepseek"]

Services - Tất cả đều forward tới HolySheep AI

[http.services] [http.services.holysheep-gpt4.loadBalancer] [[http.services.holysheep-gpt4.loadBalancer.servers]] url = "https://api.holysheep.ai/v1/chat/completions" # Headers được thêm bởi middleware service [http.services.holysheep-claude.loadBalancer] [[http.services.holysheep-claude.loadBalancer.servers]] url = "https://api.holysheep.ai/v1/chat/completions" [http.services.holysheep-gemini.loadBalancer] [[http.services.holysheep-gemini.loadBalancer.servers]] url = "https://api.holysheep.ai/v1/chat/completions" [http.services.holysheep-deepseek.loadBalancer] [[http.services.holysheep-deepseek.loadBalancer.servers]] url = "https://api.holysheep.ai/v1/chat/completions"

Node.js Smart Router Service

Đây là service xử lý intelligent routing với caching và fallback logic:

// File: ai-router-service/src/index.js
import express from 'express';
import Redis from 'ioredis';
import crypto from 'crypto';

const app = express();
app.use(express.json({ limit: '10mb' }));

// Redis connection cho caching
const redis = new Redis(process.env.REDIS_URL || 'redis://localhost:6379');
const HOLYSHEEP_API = 'https://api.holysheep.ai/v1/chat/completions';

// Model configurations với cost weights
const MODEL_CONFIG = {
    gpt4: {
        name: 'gpt-4.1',
        costPer1K: 0.008,  // Input: $8/MTok
        outputCostPer1K: 0.024,  // Output: $24/MTok
        maxTokens: 8192,
        latencyTier: 'premium',
        useFor: ['reasoning', 'complex', 'analyze', 'solve', 'code']
    },
    claude: {
        name: 'claude-sonnet-4.5',
        costPer1K: 0.015,
        outputCostPer1K: 0.075,
        maxTokens: 4096,
        latencyTier: 'premium',
        useFor: ['creative', 'write', 'story', 'narrative', 'edit']
    },
    gemini: {
        name: 'gemini-2.5-flash',
        costPer1K: 0.0025,
        outputCostPer1K: 0.010,
        maxTokens: 8192,
        latencyTier: 'fast',
        useFor: ['quick', 'fast', 'summary', 'brief']
    },
    deepseek: {
        name: 'deepseek-v3.2',
        costPer1K: 0.00042,
        outputCostPer1K: 0.00168,
        maxTokens: 4096,
        latencyTier: 'economy',
        useFor: ['batch', 'bulk', 'translate', 'classify', 'extract']
    }
};

// Intelligent model selection
function selectModel(messages, options = {}) {
    const lastMessage = messages[messages.length - 1]?.content || '';
    const lowerMessage = lastMessage.toLowerCase();
    
    // Check explicit routing header
    if (options.forceModel && MODEL_CONFIG[options.forceModel]) {
        return MODEL_CONFIG[options.forceModel];
    }
    
    // Check for keywords
    for (const [key, config] of Object.entries(MODEL_CONFIG)) {
        for (const keyword of config.useFor) {
            if (lowerMessage.includes(keyword)) {
                console.log([Router] Matched keyword '${keyword}' -> ${key});
                return { ...config, key };
            }
        }
    }
    
    // Default: DeepSeek for cost optimization
    return { ...MODEL_CONFIG.deepseek, key: 'deepseek' };
}

// Generate cache key
function getCacheKey(messages, model) {
    const content = messages.map(m => ${m.role}:${m.content}).join('|');
    const hash = crypto.createHash('sha256')
        .update(content + model.name)
        .digest('hex')
        .substring(0, 16);
    return ai:cache:${hash};
}

// Proxy request to HolySheep AI
async function proxyToAI(payload, modelConfig) {
    const response = await fetch(HOLYSHEEP_API, {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            'Authorization': Bearer ${process.env.HOLYSHEEP_API_KEY},
            'X-Model-Override': modelConfig.name
        },
        body: JSON.stringify(payload)
    });
    
    if (!response.ok) {
        const error = await response.text();
        throw new Error(HolySheep API error: ${response.status} - ${error});
    }
    
    return response.json();
}

// Main route handler
app.post('/ai/:model?', async (req, res) => {
    const startTime = Date.now();
    const { model: routeModel } = req.params;
    const { messages, temperature, max_tokens, stream, ...otherOptions } = req.body;
    
    try {
        // Select model
        const modelConfig = selectModel(messages, {
            forceModel: routeModel,
            ...otherOptions
        });
        
        console.log([Router] Selected model: ${modelConfig.name});
        
        // Check cache (cho non-streaming requests)
        if (!stream) {
            const cacheKey = getCacheKey(messages, modelConfig);
            const cached = await redis.get(cacheKey);
            
            if (cached) {
                console.log([Router] Cache HIT for key: ${cacheKey});
                const parsed = JSON.parse(cached);
                return res.json({
                    ...parsed,
                    cached: true,
                    model: modelConfig.name
                });
            }
        }
        
        // Build payload
        const payload = {
            model: modelConfig.name,
            messages,
            temperature: temperature || 0.7,
            max_tokens: Math.min(max_tokens || 2048, modelConfig.maxTokens),
            stream: stream || false,
            ...otherOptions
        };
        
        // Proxy to HolySheep AI
        const aiResponse = await proxyToAI(payload, modelConfig);
        
        // Cache response
        if (!stream && aiResponse.choices?.[0]?.message?.content) {
            const cacheKey = getCacheKey(messages, modelConfig);
            await redis.setex(cacheKey, 3600, JSON.stringify(aiResponse));
            console.log([Router] Cached response with TTL 3600s);
        }
        
        const latency = Date.now() - startTime;
        console.log([Router] Response time: ${latency}ms);
        
        res.json({
            ...aiResponse,
            routing: {
                model: modelConfig.name,
                latency_ms: latency,
                cache_hit: false
            }
        });
        
    } catch (error) {
        console.error([Router] Error:, error.message);
        
        // Fallback: try with DeepSeek if primary fails
        if (modelConfig.key !== 'deepseek') {
            console.log([Router] Falling back to DeepSeek...);
            const fallbackPayload = {
                model: 'deepseek-v3.2',
                messages,
                temperature: temperature || 0.7,
                max_tokens: 2048
            };
            
            try {
                const fallbackResponse = await proxyToAI(fallbackPayload, MODEL_CONFIG.deepseek);
                return res.json({
                    ...fallbackResponse,
                    routing: {
                        model: 'deepseek-v3.2',
                        fallback: true
                    }
                });
            } catch (fallbackError) {
                console.error([Router] Fallback also failed:, fallbackError.message);
            }
        }
        
        res.status(500).json({ 
            error: 'AI routing failed',
            message: error.message 
        });
    }
});

// Health check
app.get('/health', async (req, res) => {
    const redisStatus = redis.status;
    res.json({
        status: 'healthy',
        redis: redisStatus,
        timestamp: new Date().toISOString()
    });
});

const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
    console.log([AI Router] Running on port ${PORT});
    console.log([AI Router] HolySheep API: ${HOLYSHEEP_API});
});

Client Usage - Frontend Integration

Sau khi setup gateway, client code để sử dụng rất đơn giản. Tôi recommend dùng HolySheep AI vì latency chỉ <50ms và tiết kiệm 85%+ chi phí:

#!/usr/bin/env python3
"""
AI Gateway Client - Multi-Model Routing với HolySheep AI
Setup: pip install requests httpx aiohttp
"""

import os
import json
import asyncio
import hashlib
from typing import Optional, List, Dict, Any
from dataclasses import dataclass
from datetime import datetime
import requests

@dataclass
class AIMessage:
    role: str
    content: str

@dataclass  
class AIResponse:
    content: str
    model: str
    usage: Dict[str, int]
    latency_ms: float
    cached: bool = False

class HolySheepAIGateway:
    """
    Multi-model AI gateway client với intelligent routing
    """
    
    BASE_URL = "https://api.holysheep.ai/v1"
    
    def __init__(self, api_key: str):
        self.api_key = api_key
        self.session = requests.Session()
        self.session.headers.update({
            "Authorization": f"Bearer {api_key}",
            "Content-Type": "application/json"
        })
    
    def _estimate_cost(self, model: str, input_tokens: int, output_tokens: int) -> float:
        """Estimate cost theo model pricing 2026"""
        pricing = {
            "gpt-4.1": (8.00, 24.00),  # input, output per MTok
            "claude-sonnet-4.5": (15.00, 75.00),
            "gemini-2.5-flash": (2.50, 10.00),
            "deepseek-v3.2": (0.42, 1.68)
        }
        
        if model not in pricing:
            model = "deepseek-v3.2"  # default
        
        input_cost, output_cost = pricing[model]
        return (input_tokens / 1_000_000 * input_cost + 
                output_tokens / 1_000_000 * output_cost)
    
    def chat_completion(
        self,
        messages: List[Dict[str, str]],
        model: Optional[str] = None,
        temperature: float = 0.7,
        max_tokens: int = 2048,
        route_hint: Optional[str] = None
    ) -> AIResponse:
        """
        Gửi request tới AI gateway với optional model override
        """
        start_time = datetime.now()
        
        payload = {
            "