cgroups/systemd: replace deprecated dbus functions

[thaJeztah]

These are deprecated, but pkg.go.dev does not make that very clear; https://pkg.go.dev/github.com/coreos/go-systemd/v22/dbus#Conn.StopUnitContext

It also does a really lame job at pointing out that you're reading the "latest version" of an "ancient" release

relates to #2923

[thaJeztah]

Possibly we can use a context.WithTimeout() to replace the handling below, but I didn't want to make larger changes, because the last changes were fixing a bug, so didn't want to jinx it.

/cc @kolyshkin

[kolyshkin]

I was taking a look at it earlier this week, and I am not sure if the timeout can be replaced with a context.WithTimeout(). I read the code and don't quite understand it.

[cyphar]

context.TODO() is a little bit 😬 but we'd need to change all of the callers to pass context if we wanted to change it, so we can do that some other time.

[thaJeztah]

context.TODO() is a little bit 😬 but we'd need to change all of the callers to pass context if we wanted to change it

Agreed; I picked context.TODO() for that reason; it should be an indicator that something needs to be done 😉

Do you want me to open a tracking issue for that effort?

[kolyshkin]

I was preparing a similar PR but dropped it, as the changes introduced basically do two things

• fix linter warnings (replacing them with TODO);
• make backports harder.

Do you want me to open a tracking issue for that effort?

Yes please (I guess it's inevitable we add context to libcontainer's public API).

[kolyshkin]

fix linter warnings (replacing them with TODO)

Actually this is not true because coreos/go-systemd#340 and coreos/go-systemd#341 did not put "Deprecated:" as a separate paragraph (as required by and described in https://github.com/golang/go/wiki/Deprecated). This is why there are no linter warnings (or pkg.go.dev warnings, for that matter).