supervision - discussion about system services, daemon supervision, init, runlevel management, and tools such as s6 and runit
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From: "Casper Ti. Vector" <caspervector@gmail.com>
To: supervision@list.skarnet.org
Subject: Re: A program that can get exactly the log of a supervised process?
Date: Tue, 26 Oct 2021 00:00:36 +0800	[thread overview]
Message-ID: <YXbUpNsE79FPDdSI@CasperVector> (raw)
In-Reply-To: <em5f7d56ff-18c6-4902-b5ab-21f5fd4dfc7b@elzian>

On Mon, Oct 25, 2021 at 12:37:41PM +0000, Laurent Bercot wrote:
> Another question is how to piggyback loggrep into the notification
> mechanism: if loggrep is tied to the logger and not to the service,
> it doesn't have native access to the notification pipe. That means a
> specific mechanism is needed to give it cross-service access.

As has been sketched in previous mails, make loggrep a double-forking
chainloader, where the grandparent blocks (before closing the
notification fd and then chaining) until the grandchild is ready to
accept logs (after connecting to the logger and spawning the "grep";
the latter perhaps being an awk script in most cases)?

> But it's probably the least bad way to do it, [...]

I fullly agree.  This is the crux of the problem.

-- 
My current OpenPGP key:
RSA4096/0x227E8CAAB7AA186C (expires: 2022.09.20)
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  parent reply	other threads:[~2021-10-25 16:00 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <YXQyNQbpPZBKYLXC@caspervector>
2021-10-24  6:20 ` Laurent Bercot
2021-10-24  7:20   ` Casper Ti. Vector
     [not found]   ` <YXUJKWltk+OwYhtf@caspervector>
2021-10-25 12:37     ` Laurent Bercot
2021-10-25 12:57       ` Rio Liu
2021-10-25 13:26         ` Laurent Bercot
2021-10-25 16:00       ` Casper Ti. Vector [this message]
2021-10-23 16:03 Casper Ti. Vector
2023-06-22 17:44 ` Casper Ti. Vector
2023-06-22 19:39   ` Casper Ti. Vector
2023-06-22 19:43     ` Casper Ti. Vector

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