Move to S6

[modem7]

This is a WIP PR to move us to S6 and simplify + make the image more resilient.

• Added S6 (which should also fix https://github.com/borgmatic-collective/docker-borgmatic/pull/173)
• Added Docker env var to allow for docker operations within the container
• Added Cron var for additional cron jobs
• Removed dedicated Apprise package as that is now part of the Borgmatic package.
• Removed Supercronic in favour of basic cron
• Entrypoint moved to /root/etc/s6-overlay/s6-rc.d/svc-cron/run (This needs reviewing the most as there has been additional change/reversions that may need resolving/modifying).

Environment Variables

Variable	Description	Possible Values	Default
DOCKERCLI	Install DockerCLI	true	Empty
CRON	Cron times	cron time/false	0 1 *
CRON_COMMAND	Command cron will run	borgmatic --stats -v 0 2>&1	borgmatic --stats -v 0 2>&1
EXTRA_CRON	Extra cron lines	0 5 2 command1	Empty

• @Psycho0verload please could you review the changes that will be required to cover the changes that were done in #275. I haven't had time to implemented them yet, and I don't want to introduce a regression.

Once merged, this PR will: close #233 close #242 close #272 close #301

[Psycho0verload]

I will look at it in the coming days

[grantbevis]

Will wait for @Psycho0verload 's review too

[modem7]

Will wait for @Psycho0verload 's review too

As soon as @Psycho0verload gives his blessing that we haven't broken his work (once we modify the entrypoint script to match), we'll get it merged and close the linked PR's/issues.

[modem7]

The conflict can be easily resolved.

Once everything has been done and is ready to merge, I'll squash the commits, so they're neater in the history unless anyone has an issue with that.

@Psycho0verload - did you manage to get some time to have a look at the /root/etc/s6-overlay/s6-rc.d/svc-cron/run file?

[Psycho0verload]

For your information: I was able to implement my script and it works as far as I could test it. What I came across in the documentation:

YOUR_PASSPHRASE

I would extend my script for this and the push to the branch will follow today.

[Psycho0verload]

@modem7 added a PR on your Fork.

[modem7]

I have merged @Psycho0verload's PR (thank you for that), and have resolved the merge conflict.

Ready for review and final comments prior to merging.

@grantbevis @witten

[modem7]

Thank you for testing, @Psycho0verload.

Merge conflicts resolved. @witten @grantbevis - We are ready to merge.

[rcdailey]

Hey folks, I think it might be helpful to announce that if people were previously using init: true in their docker compose files, they should remove that, otherwise you get this error (not surprising, since the container is using overlay now):

s6-overlay-suexec: fatal: can only run as pid 1

I used the init setting because before overlay was introduced, there was nothing to properly handle interrupt signals in the container.

[modem7]

Hey folks, I think it might be helpful to announce that if people were previously using init: true in their docker compose files, they should remove that, otherwise you get this error (not surprising, since the container is using overlay now):

s6-overlay-suexec: fatal: can only run as pid 1

I used the init setting because before overlay was introduced, there was nothing to properly handle interrupt signals in the container.

Heya,

The readme needs updating now that we've moved to S6 regardless.

init has never really been recommended by us, nor does it work well with Borgmatic (as can be seen in #173). If people choose to use init, that's at their own discretion, but once we update the readme, we'll make sure to mention that it has S6 in, and elaborate a couple of paragraphs on what S6 does so that people are deterred from using init package.

I'd be happy to review any blurb you think may be suitable to be added to the readme so that it reduces or eliminates any confusion.

Cheers!