wait-for-it VS singularity

python:3.10.5-slim-buster is a Debian GNU/Linux 10 (buster). Follow the Debian package link given by wait-for-it, we'll eventually find this link https://packages.debian.org/source/oldoldstable/wait-for-it, I downloaded the wait-for-it_0.0~git20160501.orig.tar.gz file and extracted wait-for-it.sh out to the project root directory where setup.py, app.py, .dockerignore, Dockerfile and docker-compose.yml are.

Using countless variations of the wait for it script (they all get ignored (yes i did chmod +x)). another candidate or using it like this

I haven’t done it, but maybe you can use something like this in an ExecStartPre on the nginx systemd service, or if that doesnt work, as a separate service that nginx’s systemd service starts after

I’ve used wait-for-it with success.

https://github.com/vishnubob/wait-for-it

When start to build docker-compose, it tried to connect db first, but it seems that db didn't become reachable yet. Even added wait-for-it doesn't work.

executes 'wait-for-it.sh' to wait on the availability of port 3306 before running 'air'--using wait-for-it.sh is just an example and this shell script has to be installed as part of the Dockerfilehttps://github.com/vishnubob/wait-for-it

Yeah dockerize seems to achieve your second suggestion, someone also suggested my wait-for-it https://github.com/vishnubob/wait-for-it which seems to be similar but a bit more popular and also used in the official documentation https://docs.docker.com/compose/startup-order/ I think I'll go this route, the first option doesn't quite match what I need as all compose aren't necessarily to be started simultaneously.

Can't you use something like this? : https://github.com/vishnubob/wait-for-it . Essentially wait until you can ping redis port and then run wsgi runserver for django. However, are you sure that you can resolve redis host on swarm? Redis starts so fast that it makes me think it might be something else.

Old Singularity repo: https://github.com/apptainer/singularity

This sounds exactly like Singularity http://singularity.hpcng.org/

never used it but a very popular example of a container is docker (that link says what a container is) and singularity just looks like another container flavour (maybe specific to HPCs?)

The re-exec pattern is not the only way you can solve this in Go. I actually rebuilt a container runtime from C to Go (for the HPC market) and we had to solve this problem. We did it by essentially forking before any Go code gets run. Here’s the code for the main binary that actually spawns the container process. It’s half C, half Go. https://github.com/hpcng/singularity/tree/master/cmd/starter