tools-only LangChain Production Checklist
Overview
Comprehensive checklist for deploying LangChain applications to production with reliability, security, and performance.
Prerequisites
- LangChain application developed and tested
- Infrastructure provisioned
- CI/CD pipeline configured
Production Checklist
1. Configuration & Secrets
- All API keys in secrets manager (not env vars in code)
- Environment-specific configurations separated
- Fallback values for non-critical settings
- Configuration validation on startup
from pydantic_settings import BaseSettings
from pydantic import Field, SecretStr
class Settings(BaseSettings):
"""Validated configuration."""
openai_api_key: SecretStr = Field(..., env="OPENAI_API_KEY")
model_name: str = "gpt-4o-mini"
max_retries: int = Field(default=3, ge=1, le=10)
timeout_seconds: int = Field(default=30, ge=5, le=120)
class Config:
env_file = ".env"
settings = Settings() # Validates on import
2. Error Handling & Resilience
- Retry logic with exponential backoff
- Fallback models configured
- Circuit breaker for cascading failures
- Graceful degradation strategy
from langchain_openai import ChatOpenAI
from langchain_anthropic import ChatAnthropic
primary = ChatOpenAI(model="gpt-4o-mini", max_retries=3)
fallback = ChatAnthropic(model="claude-3-5-sonnet-20241022")
robust_llm = primary.with_fallbacks([fallback])
3. Observability
- Structured logging configured
- Metrics collection enabled
- Distributed tracing (LangSmith or OpenTelemetry)
- Alerting rules defined
import os
# LangSmith tracing
os.environ["LANGCHAIN_TRACING_V2"] = "true"
os.environ["LANGCHAIN_API_KEY"] = settings.langsmith_api_key
os.environ["LANGCHAIN_PROJECT"] = "production"
# Prometheus metrics
from prometheus_client import Counter, Histogram
llm_requests = Counter("langchain_llm_requests_total", "Total LLM requests")
llm_latency = Histogram("langchain_llm_latency_seconds", "LLM latency")
4. Performance
- Caching configured for repeated queries
- Connection pooling enabled
- Timeout limits set
- Batch processing for bulk operations
from langchain_core.globals import set_llm_cache
from langchain_community.cache import RedisCache
import redis
# Production caching with Redis
redis_client = redis.Redis.from_url(os.environ["REDIS_URL"])
set_llm_cache(RedisCache(redis_client))
5. Security
- Input validation implemented
- Output sanitization enabled
- Rate limiting per user/IP
- Audit logging for all LLM calls
from langchain_core.runnables import RunnableLambda
def validate_input(input_data: dict) -> dict:
"""Validate and sanitize input."""
user_input = input_data.get("input", "")
if len(user_input) > 10000:
raise ValueError("Input too long")
return input_data
secure_chain = RunnableLambda(validate_input) | prompt | llm
6. Testing
- Unit tests for all chains
- Integration tests with mock LLMs
- Load tests completed
- Chaos engineering (failure injection)
# pytest.ini
[pytest]
markers =
unit: Unit tests
integration: Integration tests
load: Load tests
7. Deployment
- Health check endpoint
- Graceful shutdown handling
- Rolling deployment strategy
- Rollback procedure documented
from fastapi import FastAPI
from contextlib import asynccontextmanager
@asynccontextmanager
async def lifespan(app: FastAPI):
# Startup
print("Warming up LLM connections...")
yield
# Shutdown
print("Cleaning up...")
app = FastAPI(lifespan=lifespan)
@app.get("/health")
async def health_check():
return {"status": "healthy", "model": settings.model_name}
8. Cost Management
- Token counting implemented
- Usage alerts configured
- Cost allocation by tenant/feature
- Budget limits enforced
import tiktoken
def estimate_cost(text: str, model: str = "gpt-4o-mini") -> float:
"""Estimate API cost for text."""
encoding = tiktoken.encoding_for_model(model)
tokens = len(encoding.encode(text))
# Approximate pricing (check current rates)
cost_per_1k = {"gpt-4o-mini": 0.00015, "gpt-4o": 0.005}
return (tokens / 1000) * cost_per_1k.get(model, 0.001)
Deployment Validation Script
#!/usr/bin/env python3
"""Pre-deployment validation script."""
def run_checks():
checks = []
# Check 1: API key configured
try:
settings = Settings()
checks.append(("API Key", "PASS"))
except Exception as e:
checks.append(("API Key", f"FAIL: {e}"))
# Check 2: LLM connectivity
try:
llm = ChatOpenAI(model="gpt-4o-mini")
llm.invoke("test")
checks.append(("LLM Connection", "PASS"))
except Exception as e:
checks.append(("LLM Connection", f"FAIL: {e}"))
# Check 3: Cache connectivity
try:
redis_client.ping()
checks.append(("Cache (Redis)", "PASS"))
except Exception as e:
checks.append(("Cache (Redis)", f"FAIL: {e}"))
for name, status in checks:
print(f"[{status}] {name}")
return all("PASS" in status for _, status in checks)
if __name__ == "__main__":
exit(0 if run_checks() else 1)
Resources
Next Steps
After launch, use langchain-observability for monitoring.