🚀 GopherLoad: High-Performance Distributed HTTP Benchmarking Suite

(C) Context

You are a Principal Systems Engineer and Performance Specialist with deep expertise in the Go (Golang) network stack. Your objective is to design a CLI-based benchmarking tool that rivals industry standards like wrk, hey, and k6, utilizing Go's first-class concurrency primitives and efficiency.

(O) Objective

Build a high-performance HTTP benchmarking tool in Go that includes:

1. Core Engine: * Concurrent request generation using goroutines and worker pools.
   • Full support for HTTP/1.1, HTTP/2, and HTTP/3 (QUIC).
   • Configurable thread count (concurrency level) and request limits.
2. Traffic Control:
   • Load Profiles: Implementation of ramp-up periods and steady-state phases.
   • Distributed Mode: A master-worker architecture to orchestrate high-load tests across multiple nodes.
3. Request Customization:
   • Support for custom headers, cookies, and TLS configuration (including skipping verification or providing CA certs).
   • Request Templating: Dynamic content generation (e.g., injecting timestamps or UUIDs into payloads).
4. Validation & Metrics:
   • Response Validation: Assertions based on HTTP status codes and Regex pattern matching on response bodies.
   • Statistical Analysis: Real-time calculation of latency (p50, p95, p99), throughput (RPS), and error rates.
   • Visual Reporting: Terminal-based histograms and detailed JSON/CSV export capabilities.

(S) Style

• Concurrency Model: Use sync.WaitGroup, channels, and context.Context for clean lifecycle management.
• Networking: Utilize net/http for 1.1/2 and quic-go for HTTP/3 support.
• CLI Design: Implement a clean command-line interface using cobra or urfave/cli.
• Architecture: Modular design with a clear separation between the Load Generator, the Results Aggregator, and the Reporter.

(T) Tone

Technical, authoritative, and efficiency-focused.

(A) Audience

DevOps engineers, SREs, and Backend Developers needing to stress-test microservices and high-traffic APIs.

(R) Response Format

Provide a structured Go project blueprint including:

• main.go: CLI entry point and orchestration.
• engine/worker.go: The core request loop and concurrency logic.
• metrics/stats.go: The logic for calculating percentiles and histograms.
• config/profile.go: Structs for load profiles and request templates.
• Instructions for building and running the distributed worker nodes.