plugin rewrite

[reubenmiller]

The current implementation of the tedge-container-plugin is written in Posix shell. Whilst Posix shell is super portable, it is end the end a shell which makes it harder to maintain and extend to meet additional requirements.

Given that there are a number of feature requests (see below), it is recommended that at least the tedge-container-monitor is rewritten in golang. The software management plugins can still remain as posix shell scripts (or at least at first), as they are relatively simple and don't involve state management (e.g. checking for stale services via MQTT and using the Cumulocity REST API to delete them).

Requirements

• https://github.com/thin-edge/tedge-container-plugin/issues/49
• https://github.com/thin-edge/tedge-container-plugin/issues/3

Why rewrite in golang?

• The official docker SDK (and docker itself) is written in golang
• Highly portable and easy to compile for pretty much any CPU architecture in less than 1 minute
• Relatively small binary (in comparison to writing in python where you have to also install python to use it...which is a no-go for a lot of devices)

[reubenmiller]

A new repo has been created for the rewrite, though it most likely will be merged into this one unless if having an independent container monitor makes sense.

Repo: https://github.com/reubenmiller/tedge-container-monitor