Implementation eines programmatischen Interfaces zum Task-Server

diff --git a/SL/System/TaskServer.pm b/SL/System/TaskServer.pm
new file mode 100644 (file)
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+++ b/SL/System/TaskServer.pm
@@ -0,0 +1,185 @@
+package SL::System::TaskServer;
+
+use strict;
+
+use parent qw(Rose::Object);
+
+use Rose::Object::MakeMethods::Generic (
+  scalar => [ qw(last_command_output) ],
+);
+
+use File::Slurp;
+use File::Spec::Functions qw(:ALL);
+
+use SL::System::Process;
+
+use constant {
+  OK           =>  0,
+  ERR_PID_FILE => -1,
+  ERR_PROCESS  => -2,
+};
+
+sub status {
+  my ($self) = @_;
+
+  my $pid = $self->_read_pid;
+  return ERR_PID_FILE unless $pid;
+
+  return kill(0, $pid) ? OK : ERR_PROCESS;
+}
+
+sub is_running {
+  my ($self) = @_;
+
+  return $self->status == OK;
+}
+
+sub start {
+  my ($self) = @_;
+
+  return $self->_run_script_command('start');
+}
+
+sub stop {
+  my ($self) = @_;
+
+  return $self->_run_script_command('stop');
+}
+
+sub wake_up {
+  my ($self) = @_;
+
+  my $pid = $self->_read_pid;
+  return undef unless $pid;
+  return kill('ALRM', $pid) ? 1 : undef;
+}
+
+#
+# private methods
+#
+
+sub _read_pid {
+  my ($self) = @_;
+
+  my $exe_dir       = SL::System::Process->exe_dir;
+  my $pid_file_name = join '.', splitdir($exe_dir), 'config.lx_office.conf.pid';
+  my $pid_file_path = catfile(catdir($exe_dir, 'users', 'pid'), $pid_file_name);
+
+  return undef unless -f $pid_file_path;
+  return join('', read_file($pid_file_path)) * 1;
+}
+
+sub _run_script_command {
+  my ($self, $command) = @_;
+
+  my $exe = catfile(catdir(SL::System::Process->exe_dir, 'scripts'), 'task_server.pl');
+  $self->last_command_output(`${exe} ${command}`);
+
+  return $? == 0 ? 1 : undef;
+}
+
+1;
+__END__
+
+=pod
+
+=encoding utf8
+
+=head1 NAME
+
+SL::System::TaskServer - programmatic interface to the external task server component
+
+=head1 SYNOPSIS
+
+  # Create interface
+  my $task_server = SL->TaskServer->new;
+
+  # Start the server if it is not running
+  if (!$task_server->is_running) {
+    $task_server->start;
+  }
+
+  # Stop it if it is running
+  if ($task_server->is_running) {
+    $task_server->stop;
+  }
+
+=head1 FUNCTIONS
+
+=over 4
+
+=item C<is_running>
+
+Returns C<trueish> if the server is running. This is done by using
+Perl's C<kill> function with a "signal" of C<0> for the process ID
+which in turn is read from the daemon's PID file.
+
+If the PID file is not found or if C<kill> returns a non-successful
+value then a C<falsish> value is returned.
+
+=item C<last_command_output>
+
+Returns the output of the last C<system> command executed, e.g. from a
+call to L<start> or L<stop>.
+
+=item C<start>
+
+Starts the task server. Does not check whether or not it is running,
+neither before not after trying to start it.
+
+Returns C<1> if the system command C<./scripts/task_server.pl start>
+exits with an exit code of C<0> and C<undef> otherwise.
+
+The command's output can be queried with L<last_command_output>.
+
+=item C<status>
+
+Queries the task server status. Returns one of these values:
+
+=over 4
+
+=item *
+
+C<OK> or C<0>: the task server is running and signals can be sent to
+it.
+
+=item *
+
+C<ERR_PID_FILE> or C<-1>: the PID file could not be found or read
+
+=item *
+
+C<ERR_PROCESS> or C<-2>: the PID file could was found and read, but
+it's not possible to send signals to the process, e.g. because it is
+not running or owned by a different user ID.
+
+=back
+
+=item C<stop>
+
+Stops the task server. Does not check whether or not it is running,
+neither before not after trying to start it.
+
+Returns C<1> if the system command C<./scripts/task_server.pl stop>
+exits with an exit code of C<0> and C<undef> otherwise.
+
+The command's output can be queried with L<last_command_output>.
+
+=item C<wake_up>
+
+Sends a signal to the task server process causing it to wake up and
+process its job queue immediately.
+
+Returns C<1> if the signal could be sent and C<undef> otherwise.
+
+=back
+
+=head1 BUGS
+
+Nothing here yet.
+
+=head1 AUTHOR
+
+Moritz Bunkus E<lt>m.bunkus@linet-services.deE<gt>
+
+=cut