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"""
API Fallback Manager
Automatically switches to alternative API providers when primary fails
"""
import asyncio
import logging
from typing import Dict, List, Any, Optional, Callable
from datetime import datetime, timedelta
from enum import Enum
logger = logging.getLogger(__name__)
class ProviderStatus(Enum):
"""Provider status"""
ACTIVE = "active"
DEGRADED = "degraded"
FAILED = "failed"
COOLDOWN = "cooldown"
class APIProvider:
"""Represents an API provider with health tracking"""
def __init__(
self,
name: str,
priority: int,
fetch_function: Callable,
cooldown_seconds: int = 300,
max_failures: int = 3
):
self.name = name
self.priority = priority
self.fetch_function = fetch_function
self.cooldown_seconds = cooldown_seconds
self.max_failures = max_failures
self.failures = 0
self.total_requests = 0
self.successful_requests = 0
self.status = ProviderStatus.ACTIVE
self.last_failure_time = None
self.last_success_time = None
def record_success(self):
"""Record successful request"""
self.successful_requests += 1
self.total_requests += 1
self.failures = 0 # Reset failures on success
self.status = ProviderStatus.ACTIVE
self.last_success_time = datetime.now()
logger.info(f"✅ {self.name}: Success (total: {self.successful_requests}/{self.total_requests})")
def record_failure(self, error: Exception):
"""Record failed request"""
self.failures += 1
self.total_requests += 1
self.last_failure_time = datetime.now()
if self.failures >= self.max_failures:
self.status = ProviderStatus.COOLDOWN
logger.warning(
f"❌ {self.name}: Entering cooldown after {self.failures} failures. "
f"Last error: {str(error)}"
)
else:
self.status = ProviderStatus.DEGRADED
logger.warning(f"⚠️ {self.name}: Failure {self.failures}/{self.max_failures} - {str(error)}")
def is_available(self) -> bool:
"""Check if provider is available"""
if self.status == ProviderStatus.COOLDOWN:
# Check if cooldown period has passed
if self.last_failure_time:
cooldown_end = self.last_failure_time + timedelta(seconds=self.cooldown_seconds)
if datetime.now() >= cooldown_end:
self.status = ProviderStatus.ACTIVE
self.failures = 0
logger.info(f"🔄 {self.name}: Cooldown ended, provider reactivated")
return True
return False
return self.status in [ProviderStatus.ACTIVE, ProviderStatus.DEGRADED]
def get_health_score(self) -> float:
"""Get health score (0-100)"""
if self.total_requests == 0:
return 100.0
return (self.successful_requests / self.total_requests) * 100
class APIFallbackManager:
"""
Manages API fallback across multiple providers
Usage:
manager = APIFallbackManager("OHLCV")
manager.add_provider("Binance", 1, fetch_binance_ohlcv)
manager.add_provider("CoinGecko", 2, fetch_coingecko_ohlcv)
result = await manager.fetch_with_fallback(symbol="BTC", timeframe="1h")
"""
def __init__(self, service_name: str):
self.service_name = service_name
self.providers: List[APIProvider] = []
logger.info(f"📡 Initialized fallback manager for {service_name}")
def add_provider(
self,
name: str,
priority: int,
fetch_function: Callable,
cooldown_seconds: int = 300,
max_failures: int = 3
):
"""Add a provider to the fallback chain"""
provider = APIProvider(name, priority, fetch_function, cooldown_seconds, max_failures)
self.providers.append(provider)
# Sort by priority (lower number = higher priority)
self.providers.sort(key=lambda p: p.priority)
logger.info(f"✅ Added provider '{name}' (priority: {priority}) to {self.service_name}")
async def fetch_with_fallback(self, **kwargs) -> Dict[str, Any]:
"""
Fetch data with automatic fallback
Args:
**kwargs: Parameters to pass to fetch functions
Returns:
Dict with:
- success: bool
- data: Any (if successful)
- provider: str (which provider succeeded)
- attempts: List of attempts
- error: str (if all failed)
"""
attempts = []
last_error = None
for provider in self.providers:
if not provider.is_available():
attempts.append({
"provider": provider.name,
"status": "skipped",
"reason": f"Provider in {provider.status.value} state"
})
continue
try:
logger.info(f"🔄 {self.service_name}: Trying {provider.name}...")
start_time = datetime.now()
# Call the provider's fetch function
data = await provider.fetch_function(**kwargs)
duration = (datetime.now() - start_time).total_seconds()
provider.record_success()
attempts.append({
"provider": provider.name,
"status": "success",
"duration": duration
})
logger.info(
f"✅ {self.service_name}: {provider.name} succeeded in {duration:.2f}s"
)
return {
"success": True,
"data": data,
"provider": provider.name,
"attempts": attempts,
"health_score": provider.get_health_score()
}
except Exception as e:
last_error = e
provider.record_failure(e)
attempts.append({
"provider": provider.name,
"status": "failed",
"error": str(e),
"error_type": type(e).__name__
})
logger.warning(
f"❌ {self.service_name}: {provider.name} failed - {str(e)}"
)
# All providers failed
logger.error(
f"🚨 {self.service_name}: ALL PROVIDERS FAILED! "
f"Tried {len(attempts)} provider(s)"
)
return {
"success": False,
"data": None,
"provider": None,
"attempts": attempts,
"error": f"All providers failed. Last error: {str(last_error)}"
}
def get_status(self) -> Dict[str, Any]:
"""Get status of all providers"""
return {
"service": self.service_name,
"providers": [
{
"name": p.name,
"priority": p.priority,
"status": p.status.value,
"health_score": p.get_health_score(),
"total_requests": p.total_requests,
"successful_requests": p.successful_requests,
"failures": p.failures,
"available": p.is_available()
}
for p in self.providers
]
}
# Example usage patterns:
async def example_ohlcv_binance(symbol: str, timeframe: str, limit: int = 100):
"""Example: Fetch from Binance"""
from backend.services.binance_client import BinanceClient
client = BinanceClient()
return await client.get_ohlcv(symbol, timeframe=timeframe, limit=limit)
async def example_ohlcv_coingecko(symbol: str, timeframe: str, limit: int = 100):
"""Example: Fetch from CoinGecko (would need implementation)"""
# Implementation would go here
raise NotImplementedError("CoinGecko OHLCV not implemented yet")
async def example_news_newsapi(q: str, **kwargs):
"""Example: Fetch news from NewsAPI"""
import httpx
api_key = "968a5e25552b4cb5ba3280361d8444ab"
url = f"https://newsapi.org/v2/everything?q={q}&sortBy=publishedAt&apiKey={api_key}"
async with httpx.AsyncClient() as client:
response = await client.get(url, timeout=10.0)
response.raise_for_status()
return response.json()
async def example_news_cryptocompare(q: str, **kwargs):
"""Example: Fetch news from CryptoCompare"""
import httpx
url = f"https://min-api.cryptocompare.com/data/v2/news/?categories={q}"
async with httpx.AsyncClient() as client:
response = await client.get(url, timeout=10.0)
response.raise_for_status()
return response.json()
# Global managers (singleton pattern)
_managers: Dict[str, APIFallbackManager] = {}
def get_fallback_manager(service_name: str) -> APIFallbackManager:
"""Get or create a fallback manager for a service"""
if service_name not in _managers:
_managers[service_name] = APIFallbackManager(service_name)
return _managers[service_name]
def get_all_managers_status() -> Dict[str, Any]:
"""Get status of all fallback managers"""
return {
name: manager.get_status()
for name, manager in _managers.items()
}
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