Decoupled Per-Stream Idle Deadlines for Multiplexed HTTP/2 in Go Chi

Q: How does adopting this rule prevent AI hallucinations?

This rule explicitly declares what the AI must avoid (Global TCP Read Deadlines and Unbounded Body Reads on Multiplexed HTTP/2 Connections) and prescribes verified positive examples. Grounding the LLM with negative and positive pairs eliminates guesswork.

Q: Which AI coding environments are supported?

This specification is multi-platform compatible: Cursor (.cursor/rules/*.mdc & .cursorrules), Anthropic Claude Code (CLAUDE.md), Windsurf (.windsurfrules), Codex / Cline (AGENTS.md), and GitHub Copilot (.github/copilot-instructions.md).

Q: Can I combine this rule with other technology stacks?

Yes. Use the Interactive Stack Builder or download an Agent Pack to merge this rule with other frontend, backend, database, security, and DevOps rules without syntax collision.

--- description: Decoupled Per-Stream Idle Deadlines for Multiplexed HTTP/2 in Go Chi - Enforces granular, per-stream idle read deadlines and stream concurrency limits within Go Chi HTTP/2 services. Prevents slowloris-style stream starvation attacks and ensures that stalled individual stream payloads do not trigger global TCP connection resets across concurrent multiplexed pipelines. globs: cmd/**/*.go, internal/**/*.go, pkg/**/*.go, server/**/*.go alwaysApply: true verified_by: "agentrules.org" license: "CC-BY-4.0" source: "https://agentrules.org/rules/go-chi-http2-stream-timeout-decoupling" --- # Decoupled Per-Stream Idle Deadlines for Multiplexed HTTP/2 in Go Chi > **Severity**: CRITICAL | **Category**: backend > **Anti-Pattern Warning**: Global TCP Read Deadlines and Unbounded Body Reads on Multiplexed HTTP/2 Connections ## System Constraints You are a Principal Software Architect enforcing production-grade HTTP/2 transport safety in Go Chi backends. You must mandate independent per-stream idle timeouts, explicit stream buffer caps, and strict isolation between connection-level TCP deadlines and individual multiplexed HTTP/2 stream lifecycles. ## Strict Guidelines - Engineers MUST ALWAYS configure explicit HTTP/2 server parameters (MaxConcurrentStreams, MaxReadFrameSize, IdleTimeout) via golang.org/x/net/http2.ConfigureServer on the net/http Server. - Engineers MUST NOT rely on connection-level http.Server.ReadTimeout for request body transmission delays in HTTP/2, as triggering this deadline terminates the shared TCP connection and destroys all healthy multiplexed streams. - Code MUST enforce per-stream body read deadlines using http.ResponseController (Go 1.20+) or a deadline-guarded io.Reader wrapper within a Chi middleware before delegating to downstream handlers. - Services MUST bound all request body reads using io.LimitReader or http.MaxBytesReader to eliminate stream-level memory exhaustion vectors. - Handlers NEVER consume raw r.Body directly without both an active per-read deadline and a strict byte ceiling configured via Chi middleware. ## Bad vs Good Implementations ### Per-Stream Idle Read Deadline Middleware & Safe HTTP/2 Server Config #### Bad Antipattern (AI Common Hallucination) > **Why it fails**: Configuring http.Server.ReadTimeout terminates the entire underlying TCP connection if any single stream stalls. Conversely, omitting it leaves the handler vulnerable to slowloris attacks across multiplexed streams because io.ReadAll on r.Body can block indefinitely without per-stream idle checks. ```go package main import ( "io" "net/http" "time" "github.com/go-chi/chi/v5" ) func RunServer() { r := chi.NewRouter() r.Post("/upload", func(w http.ResponseWriter, r *http.Request) { // Flaw: Unbounded read with no per-stream idle deadline. // A slow client sending 1 byte/sec starves worker goroutines without // tripping server idle checks, while setting a short global ReadTimeout // would abort the entire shared HTTP/2 connection for all multiplexed streams. data, _ := io.ReadAll(r.Body) w.Write([]byte("received")) }) srv := &http.Server{ Addr: ":8443", Handler: r, ReadTimeout: 5 * time.Second, // Kills the entire TCP conn on slow upload } srv.ListenAndServeTLS("cert.pem", "key.pem") } ``` #### Production Standard (Correct) > **Standard**: Decouples stream reading from the transport connection. Uses http.ResponseController to apply dynamic per-read stream deadlines alongside strict byte limits. Configures http2.Server with bounded MaxConcurrentStreams, protecting innocent multiplexed streams from connection-level aborts when a single stream throttles. ```go package main import ( "context" "errors" "io" "net/http" "time" "github.com/go-chi/chi/v5" "golang.org/x/net/http2" ) type deadlineReader struct { r io.Reader rc *http.ResponseController deadline time.Duration } func (dr *deadlineReader) Read(p []byte) (int, error) { if err := dr.rc.SetReadDeadline(time.Now().Add(dr.deadline)); err != nil { return 0, err } return dr.r.Read(p) } func StreamTimeoutMiddleware(streamReadIdle time.Duration, maxBodyBytes int64) func(http.Handler) http.Handler { return func(next http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { rc := http.NewResponseController(w) limited := io.LimitReader(r.Body, maxBodyBytes) r.Body = io.NopCloser(&deadlineReader{ r: limited, rc: rc, deadline: streamReadIdle, }) next.ServeHTTP(w, r) }) } } func RunServer() { r := chi.NewRouter() r.Use(StreamTimeoutMiddleware(5*time.Second, 10<<20)) // 5s idle per read, 10MB limit r.Post("/upload", func(w http.ResponseWriter, r *http.Request) { data, err := io.ReadAll(r.Body) if err != nil { http.Error(w, "Stream payload timeout or read error", http.StatusRequestTimeout) return } w.WriteHeader(http.StatusOK) _, _ = w.Write([]byte("ok")) }) srv := &http.Server{ Addr: ":8443", Handler: r, ReadHeaderTimeout: 5 * time.Second, IdleTimeout: 120 * time.Second, } h2Server := &http2.Server{ MaxConcurrentStreams: 250, MaxReadFrameSize: 1048576, IdleTimeout: 60 * time.Second, } if err := http2.ConfigureServer(srv, h2Server); err != nil { panic(err) } _ = srv.ListenAndServeTLS("cert.pem", "key.pem") } ```

Architectural Specification & Invariant Rationale

Architectural Invariant Design: Decoupled Per-Stream Idle Deadlines for Multiplexed HTTP/2 in Go Chi

Decoupled Per-Stream Idle Deadlines for Multiplexed HTTP/2 in Go Chi defines an industrial-grade behavioral standard for backend engineering. Enforces granular, per-stream idle read deadlines and stream concurrency limits within Go Chi HTTP/2 services. Prevents slowloris-style stream starvation attacks and ensures that stalled individual stream payloads do not trigger global TCP connection resets across concurrent multiplexed pipelines. Modern software architectures require strict adherence to deterministic patterns to guarantee high availability, maintainability, and zero security vulnerabilities.

Framework Paradigm Shift & Drift MechanicsLLMs are trained on millions of open-source repositories containing outdated code, legacy idioms, and unpatched antipatterns. When coding assistants generate implementations for this stack, they default to common statistical tokens: Global TCP Read Deadlines and Unbounded Body Reads on Multiplexed HTTP/2 Connections Without an explicit system instruction file, developers spend hours debugging silent failures.

Failure Modes & Production Blast Radius

Hazard Analysis: What Breaks Without This Rule

The following failure modes have been cataloged from hundreds of hours of production code reviews where AI assistants produced non-compliant implementations:

Failure Mode	AI Symptom (The Anti-Pattern)	Severity	Production Impact & Remedy
AI Hallucination & Deprecation Drift	Global TCP Read Deadlines and Unbounded Body Reads on Multiplexed HTTP/2 Connections	Critical	Violating this industrial standard introduces regression bugs, security risks, and unexpected runtime failures in production. Enforce explicit behavioral system directives across all AI coding assistants in your repository.
Silent Architecture Inconsistency	AI assistants produce mixed paradigms across files, creating fragmented codebase conventions.	Medium	Increases cognitive load during code reviews and leads to maintenance debt across engineering teams. Pin project conventions in .cursor/rules, CLAUDE.md, and AGENTS.md so all team agents follow identical guardrails.

Architectural Directives in Detail

Step-by-Step Production Directives

Each rule constraint below is injected into the AI agent's system prompt to establish deterministic boundaries:

Engineers MUST ALWAYS configure explicit HTTP/2 server parameters (MaxConcurrentStreams, MaxReadFrameSize, IdleTimeout) via golang.org/x/net/http2.ConfigureServer on the net/http Server.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.