On 2022-11-02 We 15:09, Andrew Dunstan wrote: > On 2022-10-17 Mo 10:59, Andrew Dunstan wrote: >> 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} || $build_dir; >>> >>> >>> Buildfarm animals could set this, probably to the global lockdir (see >>> run_branches.pl). Prior to that, buildfarm owners could do that manually. >>> >>> >> The problem here is that Cluster.pm doesn't have any idea where the >> build directory is, or even if there is one present at all. >> >> meson does appear to let us know that, however, with MESON_BUILD_ROOT, >> so probably the best thing would be to use PG_PORT_LOCKDIR if it's set, >> otherwise MESON_BUILD_ROOT if it's set, otherwise the tmp_check >> directory. If we want to backport to the make system we could export >> top_builddir somewhere. >> >> > Here's a patch which I think does the right thing. > > >
Updated with a couple of thinkos fixed. cheers andrew -- Andrew Dunstan EDB: https://www.enterprisedb.com
diff --git a/src/test/perl/PostgreSQL/Test/Cluster.pm b/src/test/perl/PostgreSQL/Test/Cluster.pm index d80134b26f..aceca353d3 100644 --- a/src/test/perl/PostgreSQL/Test/Cluster.pm +++ b/src/test/perl/PostgreSQL/Test/Cluster.pm @@ -93,9 +93,9 @@ use warnings; use Carp; use Config; -use Fcntl qw(:mode); +use Fcntl qw(:mode :flock :seek O_CREAT O_RDWR); use File::Basename; -use File::Path qw(rmtree); +use File::Path qw(rmtree mkpath); use File::Spec; use File::stat qw(stat); use File::Temp (); @@ -109,7 +109,7 @@ use Time::HiRes qw(usleep); use Scalar::Util qw(blessed); our ($use_tcp, $test_localhost, $test_pghost, $last_host_assigned, - $last_port_assigned, @all_nodes, $died); + $last_port_assigned, @all_nodes, $died, $portdir); # the minimum version we believe to be compatible with this package without # subclassing. @@ -140,6 +140,27 @@ INIT # Tracking of last port value assigned to accelerate free port lookup. $last_port_assigned = int(rand() * 16384) + 49152; + + # Set the port lock directory + + # If we're told to use a directory (e.g. from a buildfarm client) + # explicitly, use that + $portdir = $ENV{PG_TEST_PORT_DIR}; + # Otherwise, try to use a directory at the top of the build tree + if (! $portdir && $ENV{MESON_BUILD_ROOT}) + { + $portdir = $ENV{MESON_BUILD_ROOT} . '/portlock' + } + elsif (! $portdir && ($ENV{TESTDATADIR} || "") =~ /\W(src|contrib)\W/p) + { + my $dir = ${^PREMATCH}; + $portdir = "$dir/portlock" if $dir; + } + # As a last resort use a directory under tmp_check + $portdir ||= $PostgreSQL::Test::Utils::tmp_check . '/portlock'; + $portdir =~ s!\\!/!g; + # Make sure the directory exists + mkpath($portdir) unless -d $portdir; } =pod @@ -1505,6 +1526,7 @@ sub get_free_port last; } } + $found = _reserve_port($port) if $found; } } @@ -1535,6 +1557,38 @@ sub can_bind return $ret; } +# Internal routine to reserve a port number +# Returns 1 if successful, 0 if port is already reserved. +sub _reserve_port +{ + my $port = shift; + # open in rw mode so we don't have to reopen it and lose the lock + sysopen(my $portfile, "$portdir/$port.rsv", O_RDWR|O_CREAT) + || die "opening port file"; + # take an exclusive lock to avoid concurrent access + flock($portfile, LOCK_EX) || die "locking port file"; + # see if someone else has or had a reservation of this port + my $pid = <$portfile>; + chomp $pid; + if ($pid +0 > 0) + { + if (kill 0, $pid) + { + # process exists and is owned by us, so we can't reserve this port + close($portfile); + return 0; + } + } + # All good, go ahead and reserve the port, first rewind and truncate. + # If truncation fails it's not a tragedy, it just might leave some + # trailing junk in the file that won't affect us. + seek($portfile, 0, SEEK_SET); + truncate($portfile, 0); + print $portfile "$$\n"; + close($portfile); + return 1; +} + # Automatically shut down any still-running nodes (in the same order the nodes # were created in) when the test script exits. END