pwru VS lnav

if you have a recent enough kernel, this change https://github.com/cilium/pwru/pull/148 means that it will print the reason the packet was dropped in the output - see https://lwn.net/Articles/885729/

There's a whole heap of reasons a packet can be dropped:

[pwru](https://github.com/cilium/pwru) is a fun new tool from the Cilium folks for tracing network packets in the kernel. Like tcpdump but it shows you the full path including kernel syscalls. Lets you debug much deeper than "when the packet gets to this port it gets dropped".

I recently came across another useful utility for debugging unexpected packet drops - PWRU[0] (Packet, Where Are You) by Cilium.

It uses eBPF to try to trace the path of the packet through the kernel. Haven't needed to use it yet, but it could have saved me a lot of trouble in the past.

[0]: https://github.com/cilium/pwru

See https://lnav.org for a powerful mini-ETL CLI power tool; it embeds SQLite, supports ~every format, has great UX and easily handles a few million rows at a time.

The code base seems like a good reference as a small Python project.

My fav option in this class of apps: https://lnav.org/ It lets you use journalctl with pipes as requested here: https://github.com/Textualize/toolong/issues/4

For local development, I cannot recommend lnav[1] enough. Discovering this tool was a game changer in my day to day life. Adding comments, filtering in/out, prettify and analyse distribution is hard to live without now.

I don't think a browser tool would fit in my workflow. I need to pipe the output to the tool.

[1] https://lnav.org/

It looks like they run an SSH server inside a Docker container defined by this Dockerfile [1]. This uses the ForceCommand directive in the sshd_config file to ensure that a specific command is run when a user connects (rather than the user connecting directly to a shell).

Depending on whether the user connects as the `playground` or `tutorial1` user they interact with a bash script that is either [2] or [3].

[1]: https://github.com/tstack/lnav/blob/master/demo/Dockerfile

[2]: https://github.com/tstack/lnav/blob/master/docs/tutorials/pl...

[3]: https://github.com/tstack/lnav/blob/master/docs/tutorials/tu...