supervision - discussion about system services, daemon supervision, init, runlevel management, and tools such as s6 and runit
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From: "Laurent Bercot" <ska-supervision@skarnet.org>
To: supervision <supervision@list.skarnet.org>
Subject: Re: s6-rc user services on Gentoo
Date: Sat, 06 Apr 2024 13:57:23 +0000	[thread overview]
Message-ID: <em5f9ca552-f922-4649-b89f-f933d04c0cb7@eef3571a.com> (raw)
In-Reply-To: <CADQ2Nw8vvGqQcZ5r2Uv5MGUVTd_2Sn1o2ZJnBsRxbWT1D7_2Aw@mail.gmail.com>


>But then, there is a problem if one actually wants the server address
>information that --print-address provides. Alexis' 'run' script for
>example wants to save that to a file (apparently in a directory
>suitable for s6-envdir). If the output is sent to the notification
>pipe instead, s6-supervise will 'eat' it while waiting for the final
>newline character, and then the information is lost.

  That is true. The option is only usable as readiness notification if 
you
don't otherwise need the information.


>And more generally, there's also the question about how 'ready'
>dbus-daemon actually is when the point in its code that prints the
>server address is reached. I can't really say without looking at the
>code; dbus-daemon has many duties once its UNIX domain socket is
>bound.

  That doesn't matter. The important thing with readiness is that clients
need to be able to send messages to the daemon. As soon as the socket is
bound, it's okay; if the daemon hasn't finished initializing yet, then
that's what kernel socket buffers are for.

  Of course, if the daemon still needs to allocate resources and can 
*fail*
after binding the socket and printing the line, that's not good, but 
well,
it's a balance between reliability and simplicity.

--
  Laurent


  reply	other threads:[~2024-04-06 13:57 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-02  4:42 Alexis
2024-04-02 10:44 ` Hoël Bézier
2024-04-02 23:44   ` Alexis
2024-04-02 20:57 ` Guillermo
2024-04-03  0:12   ` Alexis
2024-04-03 11:37   ` Laurent Bercot
2024-04-06 12:43     ` Guillermo
2024-04-06 13:57       ` Laurent Bercot [this message]
2024-04-06 15:57       ` Muhammad Mahendra Subrata
2024-04-06 18:31         ` Laurent Bercot

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