Sentinel

aws-chunked payload encoding streams large S3 uploads in signed chunks — no full-body buffering, per-chunk SigV4 integrity.

A 76-deep audit (authed via Sentinel) surfaced CRLF injection, smuggling, traversal and path leaks — the pattern that forged momo’s security mindset.

External S3 clients like aws-cli don’t send momo headers — the server detects this and downgrades client-side replication modes to server-side alternatives, ensuring replication never silently drops.

Systematic defensive coding: nil-safety, numeric overflow guards, resource lifecycle discipline, panic recovery at every boundary, and concurrency safety under -race.

Chain, Splay, and Primary-Splay replication — and the metrics-driven controller that switches between them at runtime.