[systemd-devel] custom var in sd_notify

[Umut Tezduyar Lindskog]

On Wed, Feb 28, 2018 at 7:04 PM, Lennart Poettering
<lennart at poettering.net> wrote:
> On Mo, 26.02.18 08:09, Mantas Mikulėnas (grawity at gmail.com) wrote:
>
>> > Daemons can choose to send additional variables. However, it is recommended
>> > to prefix variable names not listed above with X_.
>> > So naturally i tried
>> >
>> > sd_notify(0, "X_ANSWER=42")
>> >
>> > and apparently systemd has no problem with that, but my questions are 2
>> > now:
>> >
>> > 1) What does systemd do with this information?
>> >
>>
>> Nothing. The documentation just says in other words that "the init system
>> must not reject packets with unknown variables", but doesn't say that
>> systemd or any other init will store all of them anywhere.
>
> Currently we indeed ignore those unknown variables entirely. It has
> been requested that we expose these variables on the bus somehow. I
> think that would be an OK addition, but we need to think about the
> lifecycle of those vars then so that the vars we collect don't grow
> without bounds.

I believe this is what we do with STATUS: messages today. I was just
curious if there is a rate limit around this sd_notify interface.

UMUT

>
> Lennart
>
> --
> Lennart Poettering, Red Hat
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