Message-ID: <52266bf8-bf38-fdfa-9a77-1568f82b63b3@dunslane.net>
Date: Mon, 17 Oct 2022 10:59:32 -0400
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Subject: Re: ssl tests aren't concurrency safe due to get_free_port()
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From: Andrew Dunstan <andrew@dunslane.net>
To: Andres Freund <andres@anarazel.de>, pgsql-hackers@postgresql.org,
 Tom Lane <tgl@sss.pgh.pa.us>
References: <20221002164931.d57hlutrcz4d2zi7@awork3.anarazel.de>
 <7579f627-aad4-7a04-1a98-033cc6b3cca5@dunslane.net>
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On 2022-10-04 Tu 01:39, Andrew Dunstan wrote:
> On 2022-10-02 Su 12:49, Andres Freund wrote:
>> 2) Use a lockfile containing a pid to protect the choice of a port within a
>>    build directory. Before accepting a port get_free_port() would check if the
>>    a lockfile exists for the port and if so, if the test using it is still
>>    alive.  That will protect against racyness between multiple tests inside a
>>    build directory, but won't protect against races between multiple builds
>>    running concurrently on a machine (e.g. on a buildfarm host)
>>
>>
> I think this is the right solution. To deal with the last issue, the
> lockdir should be overrideable, like this:
>
>
>   my $port_lockdir = $ENV{PG_PORT_LOCKDIR} || $build_dir;
>
>
> Buildfarm animals could set this, probably to the global lockdir (see
> run_branches.pl). Prior to that, buildfarm owners could do that manually.
>
>

The problem here is that Cluster.pm doesn't have any idea where the
build directory is, or even if there is one present at all.

meson does appear to let us know that, however, with MESON_BUILD_ROOT,
so probably the best thing would be to use PG_PORT_LOCKDIR if it's set,
otherwise MESON_BUILD_ROOT if it's set, otherwise the tmp_check
directory. If we want to backport to the make system we could export
top_builddir somewhere.


cheers


andrew

--
Andrew Dunstan
EDB: https://www.enterprisedb.com