Go Tip: Profiling

A few months ago we started noticing issues related to what we believed, and eventually confirmed due to our NewRelic/AWS CloudWatch dashboards, were memory leaks, this quickly reminded me of the time I attended Bill Kennedy's Advanced Go Workshop where he described different ways for profiling code, back at that time the web UI for visualizing profiles was not really officially released. On a side note I highly recommend you attending any of Bill's presentations and/or workshops, they are phenomenal!

Profiling in Go reminds me of the old good days when I was profiling C programs in my first job 15 years ago, it's funny how the UX hasn't changed that much really, except for the HTTP-based profiling.

For Go there are some great official resources for getting familiar with the ecosystem, specifically:

• golang.org Diagnostics,
• Profiling Go Programs,
• Standard library: runtime/pprof
• Standard library: net/http/pprof

But perhaps the missing key is the pprof documentation where details are explained a little better, not to mention the really useful option to compare profiles using -diff_base.

For http programs the important bit to use is the handler defined in net/http/pprof in your http mux. For example using gorilla.Mux doing something like the following is enough:

import "net/http/pprof"

// ... some other relevant code here ...

router.PathPrefix("/debug/pprof/").HandlerFunc(pprof.Index)

Ideally that /debug/pprof/ is behind some sort of Auth service to avoid leaking proprietary source code.

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