Building Resilient Microservices

In distributed systems, failures are inevitable. The key is building services that can handle failures gracefully and recover automatically.

Circuit Breaker Pattern

The circuit breaker pattern prevents cascading failures by detecting when a service is unhealthy and temporarily stopping requests to it.

class CircuitBreaker:
    def __init__(self, failure_threshold=5, timeout=60):
        self.failure_count = 0
        self.failure_threshold = failure_threshold
        self.timeout = timeout
        self.last_failure_time = None
        self.state = "CLOSED"

Retry Strategies

Implementing exponential backoff with jitter helps prevent thundering herd problems:

• Start with a small delay
• Double the delay after each failure
• Add random jitter to prevent synchronized retries
• Set a maximum retry limit

Health Checks

Proper health checks are crucial:

• Liveness: Is the service running?
• Readiness: Can the service handle requests?
• Startup: Has the service fully initialized?

Timeouts and Deadlines

Always set appropriate timeouts:

• Connection timeouts
• Read/write timeouts
• Request deadlines
• Database query timeouts

Conclusion

Building resilient microservices requires careful planning and implementation of proven patterns. The investment pays off in improved reliability and user experience.