Tooling

At 9:14 a.m. on a Wednesday, I open the laptop. The daily briefing for today is already there. Above the fold: a Whoop recovery score of 62 (fine), a Wakatime row showing 4h 21m on the OpenTelemetry Go compile-time instrumentation repo yesterday, three GitHub PRs waiting on review, and a Things 3 task that has been sliding forward for nine days: Review that thing from X. Each previous day the task migrated, and the journal entry from that day is one click away. The reason it kept slipping is in those entries somewhere. ...

You can’t reproduce the bug locally, so you add a log line and redeploy. Wrong place. You add another one and redeploy again. That is the debugging loop from my GopherCon UK talk, and in this last part we’re going to shorten it: a decision rule for two zero-touch tools, then a runbook an AI coding agent (not a Java-style one) can execute. The runbook starts with one boring question: is this Go service already running, or can I rebuild it? If the service has to stay untouched, OBI (OpenTelemetry eBPF Instrumentation) is the default. If I can rebuild it and need function-level spans, otelc (OpenTelemetry Go compile-time instrumentation) is the default. The rest of the decision tree is checking privileges, Go version, collector endpoint, and whether RED metrics are enough. ...

A benchmark bot once told me that one of my pull requests made a benchmark 6–9% slower. A same-machine comparison said the pull request made it faster. Both results were stable, and they disagreed. In this last part we’ll find out how that happens, and leave with three questions and three small Go tools that tell us how far to trust a number. A loose cable Physicists have been fooled the same way, at a much larger scale. In September 2011, the OPERA collaboration announced that muon neutrinos appeared to travel faster than the speed of light. Months of rechecking found nothing wrong. The root cause, eventually, was an improperly seated fibre-optic connector in the GPS timing chain, which introduced a ~73 ns bias that made neutrinos appear to arrive early (Science called it a loose cable). A second fault, an oscillator defect, pushed the other way and partly masked the first. Once both were corrected, the 2012 re-measurements showed neutrino speed consistent with the speed of light. ...

If you work at a company that runs its own Go module proxy and you connect through a VPN, you’ve probably seen this: 1 2 Get "https://binaries.example.com/google.golang.org/grpc/@v/v1.77.0.mod": dial tcp 172.27.5.36:443: i/o timeout The module has nothing to do with your company. It’s a public dependency. Yet Go refuses to fetch it from the public proxy and just dies with a timeout. The frustrating part: you know proxy.golang.org has the module, and your config lists it as a fallback. So why doesn’t it fall through? ...

We all know better. Don’t hardcode secrets. Use a vault. Rotate your keys. We’ve been saying this for years. And then the agentic coding boom happened. Suddenly every tool wants an API key. OpenAI, Anthropic, Gemini, Groq, Mistral, Replicate—the list grows weekly. And where do those keys end up? Right there in .zshrc, in plain text, because you needed it working right now and you were going to fix it later. ...