Docker compose upgrade

[oscgonfer]

This branch is to add changes on the docker-compose example file, in particular to make use of resource limitations and better restart policies of services.

Bear in mind that there is no more version at the beginning of the file, or there shouldn't be.

#235

[timcowlishaw]

We should also look into a better way of handling host-specific docker-compose config - one option would be to have a checked-in docker-compose.example.yml and ignore docker-compose.yml itself (then update the github actions and readme to make it clear this needs to be copied), or maybe there's something in https://docs.docker.com/compose/multiple-compose-files/ we could use to copy out host-specific stuff into includes?

[timcowlishaw]

Hey Oscar! This is looking good to me - I've fixed a small syntax error in the new compose file, and also:

1. renamed to compose.yml, the new default
2. added a compose.override.local.yml for local development
3. expanded the local dev section in the readme to make it clear what this is for
4. consistently renamed docker-compose to docker compose everywhere to reflect the new recommended systax

[timcowlishaw]

Oh, i've also just split out the compose.yml file into an include for each service, which should make things more manageable!

[oscgonfer]

Hi @timcowlishaw
Very nice and neat upgrade. Thanks.

Some improvements I would suggest for documentation:

• Now we rely on docker compose > 2.20. I would suggest having a documented way to make sure people can easily see what version is needed.
• The README.md, although updated, is confusing in general (it was before already). If possible, I would ask to various sections with step by step processes for:
  • First time deployment
  • Normal operations (update, restart, etc.)
  • Test
  • Bring services down
  • Recommended setup (machine requirements -- RAM: 8GiB if using cassandra and mqtt on the same machine (TBC)) and our production setup (I can take care of that one)

[oscgonfer]

@timcowlishaw Is it OK for me to merge?
Maybe we can solve #248 (comment) documentation briefl while is fresh before merging or would you rather do it on a separate issue?

[timcowlishaw]

Hey @oscgonfer ! Aha sure thing, that sounds sensible - i can get to the documentation part later this week!