Python: Question about packaging applications docker vs pyinstaller

Question

I have a python application that I've created an executable of, using pyinstaller. The entire python interpreter is packaged into the executable with all its pip dependencies.

So now my application can run in environments where python or python modules may not be installed, but there are still some dependencies:

1) MongoDB - This is the database my application uses, and it needs to be installed on a system for it to work of course.

2) Mosquitto - This service is required because the application uses MQTT to receive/send commands.

My current method of handling this is to use a shell script which installs mongodb and mosquitto the first time when my application is deployed somewhere. I just discovered docker, and I was wondering if it is capable of packaging these 'external' dependencies into a docker image?

Is it possible for me to have one standalone "thing" which will run in any environment regardless of whether mongoDB or mosquitto are installed there?

And how exactly would I go about doing this?

(Unrelated but this application is meant to run on a raspberry pi)

Answer 1

If you adopted Docker here:

You'd still have to "separately" run the external services; they couldn't be packaged into a single artifact per se. There's a standard tool called Docker Compose that provides this capability, though, and you'd generally distribute a docker-compose.yml file that describes how to run the set of related containers.

It's unusual to distribute a Docker image as files; instead you'd push your built image to a registry (like Docker Hub, but the major public-cloud providers offer this as a hosted service, there are a couple of independent services, or you can run your own). Docker can then retrieve the image via HTTP.

Docker containers can only be run by root-equivalent users. Since you're talking about installing databases as part of your bringup process this probably isn't a concern for you, but you could run a plain-Python or pyinstallered application as an ordinary user. Anyone who can run any Docker command has unrestricted root-level access on the host.