TL;DR. golang.org/x/net/idna.Lookup.ToASCII runs UTS-46 NFKC mapping 0-9. A pre-IDNA net.ParseIP check rejects the NO_PROXY lists, TLS-SNI routers, and cookie-domain validators that TrimRight + ParseAddr golang.org/x/net/http/httpproxy, the canonical safe pattern, and two I ran into this one while writing a Go HTTP client for a private project. I idna.Lookup.ToASCII canonicalising the host The sha
At 3:17 AM on a Tuesday in Q3 2024, our production Kotlin 2.0 microservice fleet hit a 92% memory utilization threshold across 140 nodes, traced to a silent coroutine leak in Ktor 2.2’s request pipeline that had been bleeding 12MB of heap per second for 72 hours. We lost $14k in SLO credits before we found the root cause. A Couple Million Lines of Haskell: Production Engineering at Mercury (78 p