Go and enhance your calm: demolishing an HTTP/2 interop problem

Summary

The article discusses a critical issue encountered in a microservices architecture using HTTP/2, specifically related to the ErrCode=ENHANCE_YOUR_CALM error triggered by PING flood attacks. It details how a misconfiguration in a Go client led to excessive PING frames being sent, causing Cloudflare's defenses to close the connection. The authors provide insights into the HTTP/2 protocol's features, the importance of reading response bodies, and strategies for debugging such issues. The article emphasizes the need for developers to understand the implications of HTTP/2 features and to implement best practices to avoid similar pitfalls.

Key Learnings

• 1Understanding the nuances of HTTP/2 features is crucial to avoid triggering denial-of-service mitigations.
• 2Always read HTTP response bodies in Go to prevent unnecessary PING and RST_STREAM frames that can lead to connection closures.
• 3Utilizing packet captures and detailed logging can help diagnose and resolve interop issues effectively.
• 4The design of microservices should consider the implications of using edge services like Cloudflare for internal communication.
• 5Dogfooding internal services can provide valuable insights that improve customer-facing products.

Who Should Read This

Senior Backend Engineers with experience in Go and microservices architecture facing HTTP/2 communication challenges

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