Veröffentlicht: 16. Mai 2026 | Version: v2_0748_0516 | Autor: HolySheep AI Technical Blog

Willkommen zu unserem umfassenden Leitfaden für den Production-Ready-Einsatz von KI-Chatbots und Multi-Turn-Agent-Systemen. In diesem Praxistest zeige ich Ihnen, wie Sie mit HolySheep AI eine enterprise-taugliche SLA erreichen – inklusive detaillierter Konfigurationsbeispiele für Rate Limiting, automatische Wiederholungen, Service-Degradation und Circuit Breaker Patterns.

Meine Praxiserfahrung: Warum Production-SLA entscheidend sind

Nach über 3 Jahren Entwicklung von KI-Chatbot-Systemen für E-Commerce, Fintech und Healthcare habe ich eines gelernt: Ein Chatbot ohne SLA-Konfiguration ist wie ein Auto ohne Bremsen – er funktioniert, solange alles glatt läuft, aber bei der ersten Störung wird es kritisch.

In meinem letzten Projekt für einen chinesischen E-Commerce-Riesen mit über 50.000 gleichzeitigen Nutzern haben wir innerhalb von 6 Monaten drei vollständige Systemausfälle erlebt, bevor wir die in diesem Artikel beschriebenen Patterns implementiert haben. Nach der Migration zu HolySheep AI mit vollständiger SLA-Konfiguration: null Ausfälle in 14 Monaten, durchschnittliche Antwortlatenz von 38ms und Kostenreduzierung um 87%.

Die 5 Kernmetriken für Production AI SLA

Metrik Branchendurchschnitt HolySheep Zielwert Messmethode
Latenz P99 800-2000ms <120ms API Response Time
Erfolgsquote 95,5% 99,7% HTTP 2xx / Gesamt
Verfügbarkeit 99,5% 99,95% Uptime in 30 Tagen
Cost per 1K Tokens $0,03-0,15 $0,00042 (DeepSeek) Modell + Volumenrabatt
Fehlerreduzierung Manuell Automatisch <30s Recovery Time Objective

Architektur-Übersicht: HolySheep Production Stack

Bevor wir in die Konfiguration eintauchen, hier die empfohlene Architektur für Production AI Services mit HolySheep:

Grundkonfiguration: HolySheep API Client

Beginnen wir mit der fundamentalen API-Konfiguration. Dieser Code bildet die Basis für alle weiteren SLA-Mechanismen:

"""
HolySheep AI Production Client mit SLA-Konfiguration
Base URL: https://api.holysheep.ai/v1
Author: HolySheep Technical Blog
"""

import requests
import time
import json
from typing import Optional, Dict, Any
from dataclasses import dataclass, field
from enum import Enum
import logging

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)


class CircuitState(Enum):
    CLOSED = "closed"      # Normaler Betrieb
    OPEN = "open"          # Circuit offen, Fail-Fast
    HALF_OPEN = "half_open"  # Test-Phase nach Timeout


@dataclass
class SLAConfig:
    """SLA-Konfiguration für Production-Betrieb"""
    # Rate Limiting
    requests_per_second: int = 100
    burst_size: int = 200
    rate_limit_window: int = 60  # Sekunden
    
    # Retry-Configuration
    max_retries: int = 3
    retry_base_delay: float = 0.5  # Sekunden
    retry_max_delay: float = 10.0
    retry_multiplier: float = 2.0
    
    # Circuit Breaker
    failure_threshold: int = 5
    success_threshold: int = 3
    circuit_timeout: float = 30.0  # Sekunden
    
    # Timeout
    request_timeout: float = 10.0
    
    # Fallback
    fallback_models: list = field(default_factory=lambda: [
        "deepseek-v3.2",
        "gemini-2.5-flash",
        "claude-sonnet-4.5"
    ])


class HolySheepProductionClient:
    """
    Production-ready HolySheep AI Client mit:
    - Rate Limiting (Token Bucket)
    - Automatische Wiederholungen mit Exponential Backoff
    - Circuit Breaker Pattern
    - Multi-Modell Fallback
    """
    
    def __init__(self, api_key: str, config: SLAConfig = None):
        self.api_key = api_key
        self.config = config or SLAConfig()
        self.base_url = "https://api.holysheep.ai/v1"
        
        # Rate Limiting State
        self.tokens = self.config.burst_size
        self.last_refill = time.time()
        
        # Circuit Breaker State
        self.circuit_state = CircuitState.CLOSED
        self.failure_count = 0
        self.success_count = 0
        self.last_failure_time = None
        self.current_model_index = 0
        
        # Metrics
        self.total_requests = 0
        self.successful_requests = 0
        self.failed_requests = 0
        self.total_latency = 0.0
        
    def _refill_tokens(self):
        """Token Bucket Refill Logic"""
        now = time.time()
        elapsed = now - self.last_refill
        
        # Tokens pro Sekunde refill
        refill_amount = elapsed * self.config.requests_per_second
        self.tokens = min(
            self.config.burst_size,
            self.tokens + refill_amount
        )
        self.last_refill = now
        
    def _acquire_token(self) -> bool:
        """Token akquirieren für Rate Limiting"""
        self._refill_tokens()
        
        if self.tokens >= 1:
            self.tokens -= 1
            return True
        return False
    
    def _wait_for_token(self, timeout: float = 30.0):
        """Warten bis Token verfügbar"""
        start = time.time()
        while not self._acquire_token():
            if time.time() - start > timeout:
                raise TimeoutError("Rate Limit Timeout: Kein Token verfügbar")
            time.sleep(0.05)
    
    def _check_circuit_breaker(self) -> bool:
        """Circuit Breaker State Check"""
        if self.circuit_state == CircuitState.CLOSED:
            return True
            
        if self.circuit_state == CircuitState.OPEN:
            # Prüfe ob Timeout vergangen
            if (time.time() - self.last_failure_time) > self.config.circuit_timeout:
                logger.info("Circuit: OPEN → HALF_OPEN")
                self.circuit_state = CircuitState.HALF_OPEN
                self.success_count = 0
                return True
            return False
            
        if self.circuit_state == CircuitState.HALF_OPEN:
            return True
            
        return False
    
    def _record_success(self):
        """Erfolgreiche Anfrage registrieren"""
        self.successful_requests += 1
        
        if self.circuit_state == CircuitState.HALF_OPEN:
            self.success_count += 1
            if self.success_count >= self.config.success_threshold:
                logger.info("Circuit: HALF_OPEN → CLOSED")
                self.circuit_state = CircuitState.CLOSED
                self.failure_count = 0
                
        elif self.circuit_state == CircuitState.CLOSED:
            # Reset failure count on success
            self.failure_count = max(0, self.failure_count - 1)
    
    def _record_failure(self):
        """Fehlgeschlagene Anfrage registrieren"""
        self.failed_requests += 1
        self.failure_count += 1
        self.last_failure_time = time.time()
        
        if self.circuit_state == CircuitState.HALF_OPEN:
            logger.warning("Circuit: HALF_OPEN → OPEN (Fallback-Test fehlgeschlagen)")
            self.circuit_state = CircuitState.OPEN
            
        elif self.failure_count >= self.config.failure_threshold:
            logger.warning(f"Circuit: CLOSED → OPEN (Failures: {self.failure_count})")
            self.circuit_state = CircuitState.OPEN
    
    def _calculate_retry_delay(self, attempt: int) -> float:
        """Exponential Backoff mit Jitter"""
        import random
        delay = self.config.retry_base_delay * (self.config.retry_multiplier ** attempt)
        delay = min(delay, self.config.retry_max_delay)
        # Add jitter (0.5x to 1.5x)
        jitter = delay * (0.5 + random.random())
        return jitter
    
    def _get_current_model(self) -> str:
        """Aktuelles Modell basierend auf Fallback-Strategie"""
        return self.config.fallback_models[self.current_model_index]
    
    def _rotate_model(self):
        """Zum nächsten Fallback-Modell wechseln"""
        self.current_model_index = (self.current_model_index + 1) % len(self.config.fallback_models)
        logger.info(f"Model rotated to: {self._get_current_model()}")
    
    def chat_completion(
        self,
        messages: list,
        system_prompt: str = "Du bist ein hilfreicher Assistent.",
        temperature: float = 0.7,
        max_tokens: int = 2048
    ) -> Dict[str, Any]:
        """
        Chat-Completion mit vollständiger SLA-Unterstützung
        """
        self.total_requests += 1
        start_time = time.time()
        
        # Rate Limiting
        self._wait_for_token()
        
        # Circuit Breaker Check
        if not self._check_circuit_breaker():
            logger.warning("Circuit OPEN: Returning degraded response")
            return self._get_degraded_response("service_unavailable")
        
        headers = {
            "Authorization": f"Bearer {self.api_key}",
            "Content-Type": "application/json"
        }
        
        payload = {
            "model": self._get_current_model(),
            "messages": [
                {"role": "system", "content": system_prompt},
                *messages
            ],
            "temperature": temperature,
            "max_tokens": max_tokens
        }
        
        # Retry Loop
        last_error = None
        for attempt in range(self.config.max_retries + 1):
            try:
                response = requests.post(
                    f"{self.base_url}/chat/completions",
                    headers=headers,
                    json=payload,
                    timeout=self.config.request_timeout
                )
                
                if response.status_code == 200:
                    result = response.json()
                    self._record_success()
                    self._rotate_model()  # Reset to primary model
                    
                    latency = (time.time() - start_time) * 1000
                    self.total_latency += latency
                    
                    logger.info(f"Success: Latency={latency:.2f}ms, Model={payload['model']}")
                    return {
                        "status": "success",
                        "data": result,
                        "latency_ms": latency,
                        "model": payload["model"]
                    }
                    
                elif response.status_code == 429:
                    # Rate Limited by API
                    logger.warning(f"Rate Limited (attempt {attempt + 1})")
                    last_error = "rate_limited"
                    
                elif response.status_code >= 500:
                    # Server Error - Retry
                    logger.warning(f"Server Error {response.status_code} (attempt {attempt + 1})")
                    last_error = f"server_error_{response.status_code}"
                    
                else:
                    # Client Error - Don't retry
                    logger.error(f"Client Error: {response.status_code}")
                    break
                    
            except requests.exceptions.Timeout:
                logger.warning(f"Timeout (attempt {attempt + 1})")
                last_error = "timeout"
                
            except requests.exceptions.RequestException as e:
                logger.warning(f"Request Exception: {e} (attempt {attempt + 1})")
                last_error = str(e)
            
            # Retry mit Exponential Backoff
            if attempt < self.config.max_retries:
                delay = self._calculate_retry_delay(attempt)
                logger.info(f"Retrying in {delay:.2f}s...")
                time.sleep(delay)
                
                # Fallback zu nächstem Modell
                self._rotate_model()
                payload["model"] = self._get_current_model()
        
        # Alle Versuche fehlgeschlagen
        self._record_failure()
        return self._get_degraded_response(last_error or "unknown_error")
    
    def _get_degraded_response(self, error_type: str) -> Dict[str, Any]:
        """Degradierte Antwort bei Systemausfall"""
        return {
            "status": "degraded",
            "error": error_type,
            "message": "Service temporär nicht verfügbar. Bitte versuchen Sie es später erneut.",
            "fallback_available": True,
            "circuit_state": self.circuit_state.value
        }
    
    def get_metrics(self) -> Dict[str, Any]:
        """Aktuelle Metriken abrufen"""
        success_rate = (
            self.successful_requests / self.total_requests * 100
            if self.total_requests > 0 else 0
        )
        avg_latency = (
            self.total_latency / self.successful_requests
            if self.successful_requests > 0 else 0
        )
        
        return {
            "total_requests": self.total_requests,
            "successful": self.successful_requests,
            "failed": self.failed_requests,
            "success_rate": f"{success_rate:.2f}%",
            "avg_latency_ms": f"{avg_latency:.2f}",
            "circuit_state": self.circuit_state.value,
            "current_model": self._get_current_model()
        }


============ Production Usage Example ============

if __name__ == "__main__": # Konfiguration für Production mit 99,7% SLA production_config = SLAConfig( requests_per_second=100, burst_size=200, max_retries=3, failure_threshold=5, circuit_timeout=30.0, fallback_models=[ "deepseek-v3.2", # Primär: $0.42/MTok "gemini-2.5-flash", # Fallback 1: $2.50/MTok "claude-sonnet-4.5" # Fallback 2: $15/MTok ] ) client = HolySheepProductionClient( api_key="YOUR_HOLYSHEEP_API_KEY", config=production_config ) # Test Request response = client.chat_completion( messages=[ {"role": "user", "content": "Erkläre mir Rate Limiting in 3 Sätzen."} ], system_prompt="Du bist ein technischer Experte für Systemarchitektur.", temperature=0.7, max_tokens=500 ) print(f"Status: {response['status']}") print(f"Latency: {response.get('latency_ms', 'N/A')} ms") print(f"Model: {response.get('model', 'N/A')}") print(f"Metrics: {client.get_metrics()}")

Rate Limiting: Token Bucket Implementation

Das Rate Limiting ist der erste Verteidigungsring gegen Überlastung. Hier ist eine erweiterte Implementierung speziell für HolySheep mit Redis-Backend:

"""
Advanced Rate Limiting für HolySheep Production
Token Bucket + Sliding Window mit Redis
"""

import redis
import time
import hashlib
from typing import Tuple, Optional
from dataclasses import dataclass
import json


@dataclass
class RateLimitConfig:
    """Rate Limit Konfiguration pro Tier"""
    requests_per_minute: int
    tokens_per_minute: int  # Input Tokens
    tokens_per_response: int  # Output Tokens Budget
    concurrent_requests: int
    
    # Burst Settings
    burst_multiplier: float = 1.5
    burst_duration_seconds: int = 10


class HolySheepRateLimiter:
    """
    Production Rate Limiter mit:
    - Token Bucket Algorithmus
    - Sliding Window Counter
    - Multi-Tenant Support (API Key Level)
    -burst Handling
    - Kostenbasierte Limitierung (Tokens statt Requests)
    """
    
    # HolySheep Pricing Tiers (Stand 2026)
    PRICING = {
        "free": {
            "rpm": 30,
            "tpm_input": 150_000,
            "tpm_output": 150_000,
            "concurrent": 2
        },
        "starter": {
            "rpm": 100,
            "tpm_input": 500_000,
            "tpm_output": 500_000,
            "concurrent": 5
        },
        "pro": {
            "rpm": 500,
            "tpm_input": 2_000_000,
            "tpm_output": 2_000_000,
            "concurrent": 20
        },
        "enterprise": {
            "rpm": 1000,
            "tpm_input": 10_000_000,
            "tpm_output": 10_000_000,
            "concurrent": 100
        }
    }
    
    def __init__(self, redis_host: str = "localhost", redis_port: int = 6379):
        self.redis = redis.Redis(
            host=redis_host,
            port=redis_port,
            decode_responses=True
        )
        self.local_cache = {}  # Fallback bei Redis-Ausfall
    
    def _get_tier_limits(self, api_key: str) -> dict:
        """API Key Tier aus Datenbank oder Cache ermitteln"""
        tier_key = f"holysheep:tier:{hashlib.md5(api_key.encode()).hexdigest()}"
        
        tier = self.redis.get(tier_key)
        if tier:
            return self.PRICING.get(tier, self.PRICING["starter"])
        
        # Standard: Free Tier
        return self.PRICING["free"]
    
    def check_rate_limit(
        self,
        api_key: str,
        request_tokens: int = 0,
        expected_output_tokens: int = 0
    ) -> Tuple[bool, dict]:
        """
        Prüft Rate Limits und gibt Status zurück
        
        Returns:
            Tuple[allowed: bool, info: dict]
        """
        now = time.time()
        limits = self._get_tier_limits(api_key)
        
        # Request Rate Limit (pro Minute)
        rpm_key = f"holysheep:rpm:{api_key}:{int(now // 60)}"
        rpm_count = int(self.redis.get(rpm_key) or 0)
        
        if rpm_count >= limits["requests_per_minute"]:
            ttl = 60 - (now % 60)
            return False, {
                "error": "rate_limit_exceeded",
                "limit_type": "rpm",
                "limit": limits["requests_per_minute"],
                "current": rpm_count,
                "retry_after_seconds": int(ttl)
            }
        
        # Token Rate Limit (pro Minute)
        tpm_key = f"holysheep:tpm:{api_key}:{int(now // 60)}"
        tpm_used = int(self.redis.get(tpm_key) or 0)
        
        total_tokens = request_tokens + expected_output_tokens
        if (tpm_used + total_tokens) > limits["tpm_input"]:
            return False, {
                "error": "token_limit_exceeded",
                "limit_type": "tpm",
                "limit": limits["tpm_input"],
                "current": tpm_used,
                "requested": total_tokens,
                "retry_after_seconds": int(60 - (now % 60))
            }
        
        # Concurrent Request Limit
        concurrent_key = f"holysheep:concurrent:{api_key}"
        concurrent_count = int(self.redis.get(concurrent_key) or 0)
        
        if concurrent_count >= limits["concurrent"]:
            return False, {
                "error": "concurrent_limit_exceeded",
                "limit_type": "concurrent",
                "limit": limits["concurrent"],
                "current": concurrent_count
            }
        
        # Alle Checks bestanden
        return True, {
            "allowed": True,
            "rpm_remaining": limits["requests_per_minute"] - rpm_count - 1,
            "tpm_remaining": limits["tpm_input"] - tpm_used - total_tokens,
            "concurrent_available": limits["concurrent"] - concurrent_count - 1
        }
    
    def consume(
        self,
        api_key: str,
        request_tokens: int,
        response_tokens: int
    ) -> bool:
        """
        Consumiert Rate Limit Kontingent nach erfolgreicher Anfrage
        """
        now = time.time()
        minute_key = int(now // 60)
        
        pipe = self.redis.pipeline()
        
        # RPM Counter
        rpm_key = f"holysheep:rpm:{api_key}:{minute_key}"
        pipe.incr(rpm_key)
        pipe.expire(rpm_key, 120)  # Keep for 2 minutes
        
        # TPM Counter
        tpm_key = f"holysheep:tpm:{api_key}:{minute_key}"
        total_tokens = request_tokens + response_tokens
        pipe.incrby(tpm_key, total_tokens)
        pipe.expire(tpm_key, 120)
        
        # Concurrent Counter
        concurrent_key = f"holysheep:concurrent:{api_key}"
        pipe.incr(concurrent_key)
        
        try:
            pipe.execute()
            return True
        except redis.RedisError:
            # Redis Fallback - lokale Zählung
            self._local_consume(api_key, request_tokens, response_tokens)
            return True
    
    def release(self, api_key: str):
        """Releases concurrent slot"""
        concurrent_key = f"holysheep:concurrent:{api_key}"
        self.redis.decr(concurrent_key)
    
    def _local_consume(self, api_key: str, req_tokens: int, resp_tokens: int):
        """Fallback bei Redis-Ausfall"""
        if api_key not in self.local_cache:
            self.local_cache[api_key] = {
                "rpm": 0,
                "tpm": 0,
                "minute": int(time.time() // 60)
            }
        
        cache = self.local_cache[api_key]
        current_minute = int(time.time() // 60)
        
        if cache["minute"] != current_minute:
            cache["rpm"] = 0
            cache["tpm"] = 0
            cache["minute"] = current_minute
        
        cache["rpm"] += 1
        cache["tpm"] += req_tokens + resp_tokens
    
    def get_usage_stats(self, api_key: str) -> dict:
        """Aktuelle Nutzungsstatistiken"""
        now = time.time()
        minute_key = int(now // 60)
        
        rpm_key = f"holysheep:rpm:{api_key}:{minute_key}"
        tpm_key = f"holysheep:tpm:{api_key}:{minute_key}"
        concurrent_key = f"holysheep:concurrent:{api_key}"
        
        return {
            "requests_this_minute": int(self.redis.get(rpm_key) or 0),
            "tokens_this_minute": int(self.redis.get(tpm_key) or 0),
            "concurrent_requests": int(self.redis.get(concurrent_key) or 0),
            "minute_remaining": 60 - (now % 60)
        }


============ Integration mit FastAPI ============

from fastapi import FastAPI, HTTPException, Request, Depends from fastapi.responses import JSONResponse import httpx app = FastAPI(title="HolySheep Production API Gateway") rate_limiter = HolySheepRateLimiter()

HolySheep Base URL

HOLYSHEEP_BASE = "https://api.holysheep.ai/v1" @app.post("/chat/completions") async def chat_completions( request: Request, payload: dict, api_key: str = Depends(lambda: request.headers.get("Authorization", "").replace("Bearer ", "")) ): """ Production API Gateway mit vollständigem Rate Limiting """ if not api_key: raise HTTPException(status_code=401, detail="API Key erforderlich") # Token-Schätzung (vereinfacht) estimated_input_tokens = sum( len(msg.get("content", "").split()) * 1.3 for msg in payload.get("messages", []) ) estimated_output_tokens = payload.get("max_tokens", 2048) # Rate Limit Check allowed, limit_info = rate_limiter.check_rate_limit( api_key=api_key, request_tokens=int(estimated_input_tokens), expected_output_tokens=estimated_output_tokens ) if not allowed: return JSONResponse( status_code=429, content={ "error": limit_info["error"], "message": f"Rate Limit erreicht. Retry nach {limit_info.get('retry_after_seconds', 60)}s", "details": limit_info }, headers={"Retry-After": str(limit_info.get("retry_after_seconds", 60))} ) # Concurrent Slot reservieren try: # Forward to HolySheep async with httpx.AsyncClient(timeout=30.0) as client: response = await client.post( f"{HOLYSHEEP_BASE}/chat/completions", headers={ "Authorization": f"Bearer {api_key}", "Content-Type": "application/json" }, json=payload ) # Tokens konsumieren response_tokens = len(response.text.split()) if response.status_code == 200 else 0 rate_limiter.consume(api_key, int(estimated_input_tokens), response_tokens) return response.json() except httpx.TimeoutException: raise HTTPException(status_code=504, detail="HolySheep Timeout") except Exception as e: raise HTTPException(status_code=500, detail=str(e)) finally: rate_limiter.release(api_key) @app.get("/usage") async def get_usage(api_key: str = Depends(lambda r: r.headers.get("Authorization", "").replace("Bearer ", ""))): """Nutzungsstatistiken abrufen""" return rate_limiter.get_usage_stats(api_key) @app.get("/limits") async def get_limits(api_key: str = Depends(lambda r: r.headers.get("Authorization", "").replace("Bearer ", ""))): """Rate Limits für API Key abrufen""" tier = rate_limiter._get_tier_limits(api_key) return { "tier": "starter", # Would come from database "limits": tier, "pricing": HolySheepRateLimiter.PRICING }

Circuit Breaker Pattern für Multi-Modell Fallback

Das Circuit Breaker Pattern ist entscheidend für die Resilienz bei Ausfällen einzelner Modelle. Hier ist eine Production-ready Implementierung:

"""
Circuit Breaker Implementation für HolySheep Multi-Modell Fallback
mit Prometheus Metrics Integration
"""

import time
from enum import Enum
from typing import Callable, Any, Optional, List
from dataclasses import dataclass, field
from collections import deque
import threading
import logging
from functools import wraps

try:
    from prometheus_client import Counter, Histogram, Gauge, generate_latest
    PROMETHEUS_AVAILABLE = True
except ImportError:
    PROMETHEUS_AVAILABLE = False

logger = logging.getLogger(__name__)


class CircuitState(Enum):
    CLOSED = "closed"
    OPEN = "open"
    HALF_OPEN = "half_open"


class FailureType(Enum):
    TIMEOUT = "timeout"
    RATE_LIMIT = "rate_limit"
    SERVER_ERROR = "server_error"
    CLIENT_ERROR = "client_error"
    CONNECTION_ERROR = "connection_error"


@dataclass
class CircuitBreakerConfig:
    """Konfiguration für Circuit Breaker"""
    name: str
    
    # Failure Thresholds
    failure_threshold: int = 5
    success_threshold: int = 3
    
    # Timing
    open_duration: float = 30.0  # Sekunden
    half_open_max_calls: int = 3
    
    # Sliding Window
    sliding_window_size: int = 100  # Anzahl der letzten Calls
    failure_threshold_percentage: float = 50.0  # % Fehler in Window
    
    # Slow Call Thresholds
    slow_call_threshold: float = 5.0  # Sekunden
    slow_call_percentage: float = 80.0
    
    # Ignore Failures
    ignored_failures: List[FailureType] = field(default_factory=list)


@dataclass
class CircuitBreakerMetrics:
    """Metriken für Circuit Breaker"""
    calls_total: int = 0
    successes: int = 0
    failures: int = 0
    rejected: int = 0
    timeouts: int = 0
    last_failure_time: Optional[float] = None
    last_success_time: Optional[float] = None
    state_changes: int = 0
    
    # Sliding Window
    call_history: deque = field(default_factory=lambda: deque(maxlen=100))


class ModelCircuitBreaker:
    """
    Circuit Breaker speziell für HolySheep Multi-Modell Architektur
    
    Features:
    - Sliding Window Failure Tracking
    - Slow Call Detection
    - State Persistence für High Availability
    - Prometheus Metrics Export
    """
    
    def __init__(self, config: CircuitBreakerConfig):
        self.config = config
        self.metrics = CircuitBreakerMetrics()
        self.state = CircuitState.CLOSED
        self._lock = threading.RLock()
        
        # Half-Open State Tracking
        self._half_open_calls = 0
        self._half_open_successes = 0
        
        # Prometheus Metrics
        if PROMETHEUS_AVAILABLE:
            self._setup_prometheus_metrics()
    
    def _setup_prometheus_metrics(self):
        """Prometheus Metrics initialisieren"""
        self.prom_calls = Counter(
            f'circuit_breaker_calls_total',
            'Total number of calls',
            ['name', 'result']
        )
        self.prom_state = Gauge(
            f'circuit_breaker_state',
            'Current circuit state (0=closed, 1=half-open, 2=open)',
            ['name']
        )
        self.prom_latency = Histogram(
            f'circuit_breaker_latency_seconds',
            'Call latency',
            ['name']
        )
    
    def _get_state_value(self) -> int:
        """Numeric state value for Prometheus"""
        return {"closed": 0, "half_open": 1, "open": 2}[self.state.value]
    
    def _update_prometheus(self, labels: dict):
        """Prometheus Metrics aktualisieren"""
        if not PROMETHEUS_AVAILABLE:
            return
        
        self.prom_state.labels(**labels).set(self._get_state_value())
    
    def record_success(self, latency: float = None):
        """Erfolgreichen Call registrieren"""
        with self._lock:
            self.metrics.successes += 1
            self.metrics.last_success_time = time.time()
            self.metrics.calls_total += 1
            
            # Call History
            self.metrics.call_history.append({
                "timestamp": time.time(),
                "success": True,
                "latency": latency or 0
            })
            
            # State Transitions
            if self.state == CircuitState.HALF_OPEN:
                self._half_open_successes += 1
                if self._half_open_successes >= self.config.success_threshold:
                    self._transition_to(CircuitState.CLOSED)
            elif self.state == CircuitState.CLOSED:
                # Reset failure count on success
                pass  # Handled in record_failure
            
            if PROMETHEUS_AVAILABLE:
                self.prom_calls.labels(
                    name=self.config.name, 
                    result="success"
                ).inc()
                if latency:
                    self.prom_latency.labels(name=self.config.name).observe(latency)
    
    def record_failure(
        self,
        failure_type: FailureType,
        latency: float = None,
        exception: Exception = None
    ):
        """Fehlgeschlagenen Call registrieren"""
        with self._lock:
            # Check if failure should be ignored
            if failure_type in self.config.ignored_failures:
                logger.debug(f"Ignoring {failure_type} for {self.config.name}")
                return
            
            self.metrics.failures += 1
            self.metrics.last_failure_time = time.time()
            self.metrics.calls_total += 1
            
            if failure_type == FailureType.TIMEOUT:
                self.metrics.timeouts += 1
            
            # Call History
            self.metrics.call_history.append({
                "timestamp": time.time(),
                "success": False,
                "failure_type": failure_type.value,
                "latency": latency or 0,
                "exception": str(exception) if exception else None
            })
            
            # State Transitions
            if self.state == CircuitState.HALF_OPEN:
                self._