Wakapi in Docker leaving zombie process 🧟

[baddate]

Describe the bug
running the wakapi docker container will generate a zombie process

System information

• Wakapi version 2.12.2
• Ubuntu 22.04
• Docker image with latest tag
• PgSQL

[YC]

This is what I see when I ran Wakapi 2.12.2 with Postgres 17.

root     1103040       1  0 20:32 ?        00:00:00 /usr/bin/containerd-shim-runc-v2 -namespace moby -id 0396e1b11c58286a2847b40097c6b923957276cdb2f5021804eafec8dbfe3978 -address /run/containerd/containerd.sock
999      1103091 1103040  0 20:32 ?        00:00:00  \_ postgres
999      1103239 1103091  0 20:32 ?        00:00:00      \_ postgres: checkpointer
999      1103240 1103091  0 20:32 ?        00:00:00      \_ postgres: background writer
999      1103242 1103091  0 20:32 ?        00:00:00      \_ postgres: walwriter
999      1103243 1103091  0 20:32 ?        00:00:00      \_ postgres: autovacuum launcher
999      1103244 1103091  0 20:32 ?        00:00:00      \_ postgres: logical replication launcher
999      1103262 1103091  0 20:32 ?        00:00:00      \_ postgres: wakapi wakapi 172.19.0.3(45668) idle
999      1103264 1103091  0 20:32 ?        00:00:00      \_ postgres: wakapi wakapi 172.19.0.3(45682) idle
root     1103069       1  0 20:32 ?        00:00:00 /usr/bin/containerd-shim-runc-v2 -namespace moby -id 5cfc3755f29a64d7b2b9c5c4c6ac8879897dfa7ce73d4b8c94fa8e8b21b33415 -address /run/containerd/containerd.sock
1000    1103099 1103069  0 20:32 ?        00:00:00  \_ ./wakapi
1000    1103164 1103099  0 20:32 ?        00:00:00      \_ [timeout] <defunct>

The timeout is perhaps coming from wait-for-it.sh.
https://github.com/muety/wakapi/blob/master/Dockerfile#L4
Didn't see the others.

[muety]

Can you please explain this a bit further? From your screenshot I don't quite understand what the problem is.

[baddate]

Can you please explain this a bit further? From your screenshot I don't quite understand what the problem is.

I encountered a zombie process and subsequently determined that its parent process was Wakapi.

[muety]

Alright, went a bit deeper into this, but can't really explain why this is happening. My first intuition was that - as @YC suggested - it's related to this part of the wait-for-it script. But then I'm wondering why wakapi is the parent process of that zombie? Also, I can't reproduce this outside of a container (even when using wait-for-it) so it's probably indeed related to Docker.

Here is a super interesting discussion about Docker and zombie processes in general.

Wakapi itself doesn't spawn any child processes, to the best of my knowledge (unless some external libraries / database driver / etc. do).

While a zombie process doesn't really hurt, I'd still be happy if someone with proficient Linux expertise could have a look at this. Thanks for reporting.