cdn-edge

EdgeFlow CDN edge node — high-performance HTTP/HTTPS reverse proxy with caching.

Architecture

flowchart LR
    Client[Client] --> Edge[Edge Proxy :8080]
    Edge --> MemCache[Memory Cache<br/>Sharded LRU]
    Edge --> DiskCache[Disk Cache<br/>Hash Bucketed]
    Edge --> Origin[Origin Server]
    Edge --> Metrics[Prometheus :9100]
    CP[Control Plane] -->|gRPC Config Sync| Edge
    Redis[(Redis)] -->|Pub/Sub Purge| Edge
    Edge -->|Access Logs| CH[(ClickHouse)]

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Features

• HTTP/HTTPS reverse proxy with Host-based domain routing
• Two-tier LRU cache: sharded in-memory + hash-bucketed disk
• Cache-Control header parsing (s-maxage, max-age, Expires)
• Origin fetch with singleflight request coalescing and retry
• Origin strategies: round-robin, weighted, primary-backup
• HTTPS with SNI support (TLS 1.2+, HTTP/2)
• Let's Encrypt / ACME auto certificate management
• Per-IP token bucket rate limiting
• Anti-hotlinking (Referer whitelist + signed URL)
• Prometheus metrics (/metrics) and health check (/health)
• Structured JSON access logging
• ClickHouse log shipping (async batched)
• gRPC client for control plane config sync
• Redis pub/sub for cache purge broadcast

Quick Start

# Build
go build -o bin/cdn-edge ./cmd

# Run
./bin/cdn-edge -config configs/edge-config.yaml

# Docker
docker build -t cdn-edge .
docker run -p 8080:8080 cdn-edge

Configuration

See configs/edge-config.yaml for all options.

Performance

• Memory cache Get: ~9.5M ops/sec (zero allocs)
• Full proxy cache hit: ~32K QPS (~37μs/op)
• Target: >10K QPS, P99 <5ms on cache hit

Testing

go test ./... -race -count=1
go test ./cache/... -bench=. -benchmem