[pmg-devel] [PATCH api v4 02/10] pmg-smtp-filter: move pid file into /run/pmg-smtp-filter

[Fiona Ebner]

Am 16.07.24 um 11:14 schrieb Fiona Ebner:
> CC-ing pmg-devel again
> 
> Am 15.07.24 um 14:02 schrieb Maximiliano Sandoval:
>> Fiona Ebner <f.ebner at proxmox.com> writes:
>>
>>> Am 10.07.24 um 16:35 schrieb Maximiliano Sandoval:
>>>> diff --git a/src/PMG/Utils.pm b/src/PMG/Utils.pm
>>>> index 5d9ded4..09cb42d 100644
>>>> --- a/src/PMG/Utils.pm
>>>> +++ b/src/PMG/Utils.pm
>>>> @@ -1462,7 +1462,7 @@ sub get_pg_server_version {
>>>>  
>>>>  sub reload_smtp_filter {
>>>>  
>>>> -    my $pid_file = '/run/pmg-smtp-filter.pid';
>>>> +    my $pid_file = '/run/pmg-smtp-filter/pmg-smtp-filter.pid';
>>>>      my $pid = PVE::Tools::file_read_firstline($pid_file);
>>>>  
>>>>      return 0 if !$pid;
>>>
>>> Can there be a race here during/after update? I.e. service still running
>>> with PID file in old path and reload_smtp_filter() is called only
>>> checking the new path. Does something ensure this can't happen?
>>> Otherwise, I suppose we'll need to check the old path too until the next
>>> major release.
>>>
>>> And what about the other way around, i.e. service already running with
>>> PID file in new path and old version of reload_smtp_filter() called
>>> still checking the old path?
>>
>> I am not entirely sure to be honest. Every service will be restarted
>> after the install so at most there could be races during the install
>> process.
>>
> 
> But the src/PMG/Utils.pm file is used by other services too, right?  And
> it seems likely that reload_smtp_filter() can be reached by those, e.g.
> one caller is PMG/Config.pm's rewrite_config().
> 

Since we talked off-list about this series again: maybe we can make
PMG/Utils.pm check both the new and old path right now for preparation
and then in the next major release, switch over the systemd service to
the new path?

>> I am not sure how this is handled in perl, but my understanding is that
>> the file is in memory until the service is restarted in which case I
>> don't think there should be any race in this window either.
>>