htcat VS delve

https://github.com/htcat/htcat) to assist with Heroku's efforts to speed up moving the tar formatted application releases around. It's pretty old, it doesn't integrate tar archival itself, it probably can stand improvement (or given its small size, even a rewrite).

My favorite hack in there (that also made it work with pre-signed S3 urls) was not using the HEAD method as is customary to determine object sizes, but instead doing a regular "GET" that, for small files, would execute on its own...but for larger would simply be abruptly closed by htcat once it reached the bytes that had since been fetched in parallel by a range-based request sent immediately afterwards. The goal was to have htcat not offer a penalty on small files so it could be used on blended workloads without thinking.

It also found a bug in S3's range implementation. We had a problem with some object or other, I wrote in about it, and was told that upon investigation a bug had been fixed. No more problem.

At a recent job, we had slightly different containers for local dev; our backend containers (for a Go app) had Air [1] installed for live reloading, plus Delve [2] running inside the container for VS Code's debugger to connect to. We also had a frontend container for local dev, which didn't get deployed as a container, just as static files.

[1] https://github.com/cosmtrek/air

[2] https://github.com/go-delve/delve/

https://github.com/go-delve/delve/releases/tag/v1.21.2 Thanks Derek and the rest of the team for helping us to debug in a normal way!

My employer has a commercial solution for this but Delve does supports `rr` traces natively for this purpose, which gives a complete open-source solution (https://github.com/go-delve/delve/blob/master/Documentation/usage/dlv_replay.md).

delve and related IDE integrations

For time travel debugging in Go:

The Delve debugger for Go supports debugging rr traces: https://github.com/go-delve/delve/blob/master/Documentation/...

Undo (who I work for) maintain a fork that debugs our LiveRecorder recordings: https://docs.undo.io/GoDelve.html

Either rr (https://rr-project.org/) or our UDB debugger (https://undo.io/solutions/products/udb/) can do some time travel debugging of Go programs via GDB's built-in support for Go. I believe its weakness is in support for goroutines, since they don't map well onto its idea of how programs run.

So in my case I use https://github.com/leoluz/nvim-dap-go (which itself calls out to the CLI tool https://github.com/go-delve/delve).

Clone https://github.com/go-delve/delve.git