From: Thomas Lamprecht <t.lamprecht@proxmox.com>
To: Proxmox VE development discussion <pve-devel@lists.proxmox.com>,
Dominik Csapak <d.csapak@proxmox.com>
Subject: [pve-devel] applied: [RFC PATCH common] RESTEnvironment: better SIGCHLD handling in AnyEvent event loop
Date: Tue, 7 Mar 2023 18:58:34 +0100 [thread overview]
Message-ID: <b36ca469-beeb-e911-e16b-2ec8047fa5ea@proxmox.com> (raw)
In-Reply-To: <20230220100828.3416873-1-d.csapak@proxmox.com>
On 20/02/2023 11:08, Dominik Csapak wrote:
> when we're in an API server that uses AnyEvent, we must postpone
> the worker_reaper, since it calls 'active_workers' which might already
> be called and then we're inside the lock twice (flocks are per process
> for us, see PVE::Tools::lock_file)
>
> This resulted in an error like this:
> close (rename) atomic file '/var/log/pve/tasks/active' failed: No such file or directory
>
> We use the fact that only 'pub' and 'priv' RESTEnvironment types are an
> api server with anyevent. For other types we call it like before.
>
> Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
> ---
> Not super happy about the coupling between the RESTEnvironment and AnyEvent.
> We could try to just save the worker_reaper in 'self' and let the users
> of the env decide when to call it, but that would be more involved.
>
> OTOH, we already do some anyevent specific things in PVE::Daemon
> (without depending on the AnyEvent package though)...
>
> Also i did not find a way to dynamically find out if we're in an
> AnyEvent loop...
>
> debian/control | 1 +
> src/PVE/RESTEnvironment.pm | 13 ++++++++++++-
> 2 files changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/debian/control b/debian/control
> index 232a0e4..1c75985 100644
> --- a/debian/control
> +++ b/debian/control
> @@ -3,6 +3,7 @@ Section: perl
> Priority: optional
> Maintainer: Proxmox Support Team <support@proxmox.com>
> Build-Depends: debhelper (>= 12~),
> + libanyevent-perl,
if we manage to guard calling into anyevent correctly it would not really be a
hard-dependency; OTOH, in practice not much (nothing?) would change so not really
that hard feelings either - especially as you mention the use in PVE::Daemon ..
> libclone-perl,
> libdevel-cycle-perl,
> libfilesys-df-perl,
> diff --git a/src/PVE/RESTEnvironment.pm b/src/PVE/RESTEnvironment.pm
> index bf89c12..c258b1e 100644
> --- a/src/PVE/RESTEnvironment.pm
> +++ b/src/PVE/RESTEnvironment.pm
> @@ -14,6 +14,7 @@ use IO::File;
> use IO::Handle;
> use IO::Select;
> use POSIX qw(:sys_wait_h EINTR);
> +use AnyEvent;
>
> use PVE::Exception qw(raise raise_perm_exc);
> use PVE::INotify;
> @@ -111,7 +112,17 @@ sub init {
> die "unknown environment type"
> if !$type || $type !~ m/^(cli|pub|priv|ha)$/;
>
> - $SIG{CHLD} = $worker_reaper;
> + my $has_anyevent = $type eq 'pub' || $type eq 'priv';
> +
meh, I'd like some more direct check, FWIW, we could check for `$INC{'AnyEvent.pm'}` if
that's any use here? I hoped $AnyEvent::MODEL could be used, but from a very quick test
it was uninitialized, maybe I held it wrong..
> + $SIG{CHLD} = sub {
> + # when we're in an api server, we have to postpone the call to worker_reaper, otherwise it
> + # might interfere with running api calls
> + if ($has_anyevent) {
> + AnyEvent::postpone { $worker_reaper->() };
> + } else {
> + $worker_reaper->();
> + }
> + };
>
> # environment types
> # cli ... command started fron command line
Anyhow: applied for now, thanks! Finding a better way to detect if this is required would
be still nice though. if anybody got ideas please lets hear them ;-)
prev parent reply other threads:[~2023-03-07 17:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-20 10:08 [pve-devel] " Dominik Csapak
2023-02-20 10:33 ` Wolfgang Bumiller
2023-03-07 17:58 ` Thomas Lamprecht [this message]
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