src/commands/1plus1

   1 #!/usr/bin/perl
   2 use strict;
   3 use warnings;
   4
   5 # import LOCK_*
   6 use Fcntl qw(:flock);
   7
   8 my $lockbase      = shift;    # suggested: $GL_REPO_BASE/$GL_REPO.git/.gl-mirror-push-lock.$SLAVE_NAME
   9 my @cmd_plus_args = @ARGV;    # the actual 'gitolite mirror ...' command
  10 @ARGV = ();
  11
  12 # ----------------------------------------------------------------------
  13
  14 open( my $fhrun, ">", "$lockbase.run" ) or die "open '$lockbase.run' failed: $!";
  15 if ( flock( $fhrun, LOCK_EX | LOCK_NB ) ) {
  16     # got run lock; you're good to go
  17
  18     system(@cmd_plus_args);
  19
  20     flock( $fhrun, LOCK_UN );
  21     exit 0;
  22 }
  23
  24 # "run" lock failed; someone is already running the command
  25
  26 open( my $fhqueue, ">", "$lockbase.queue" ) or die "open '$lockbase.queue' failed: $!";
  27 if ( flock( $fhqueue, LOCK_EX | LOCK_NB ) ) {
  28     # got queue lock, now block waiting for "run" lock
  29     flock( $fhrun, LOCK_EX );
  30     # got run lock, so take yourself out of "queue" state, then run
  31     flock( $fhqueue, LOCK_UN );
  32
  33     system(@cmd_plus_args);
  34
  35     flock( $fhrun, LOCK_UN );
  36     exit 0;
  37 }
  38
  39 # "queue" lock also failed; someone is running AND someone is queued; we can go home
  40 say STDERR "INFO: nothing to do/queue; '$lockbase' already running and 1 in queue";
  41 exit 0;