#!/usr/bin/perl

use common::sense;
use DBI;
use DBD::Pg qw/:async/;
use AnyEvent;
use POSIX qw/SIGTERM SIGINT SIG_BLOCK SIG_UNBLOCK/;

sub query {
  my $sql=pop;
  state $dbh||=DBI->connect('dbi:Pg:dbname=r2', 'ipp', undef, {RaiseError=>1});
  my $stmt=$dbh->prepare($sql, {pg_async=>PG_ASYNC});

  my $done=AE::cv;
  my $cancel=sub {
    $dbh->pg_cancel if $dbh->{pg_async_status}==1;
    $done->send;
  };
  my $pg_w=AE::io $dbh->{pg_socket}, 0, sub {
    $dbh->pg_ready and $done->send;
  };

  my $sigblock=POSIX::SigSet->new(SIGTERM, SIGINT);
  POSIX::sigprocmask SIG_BLOCK, $sigblock;
  my @sig_w=map {AE::signal $_, $cancel} qw/TERM INT/;
  $stmt->execute(@_);
  POSIX::sigprocmask SIG_UNBLOCK, $sigblock;

  $done->wait;

  return $dbh->{pg_async_status}==1 ? ($dbh->pg_result, $stmt) : ();
}

print "Status: 200\nContent-Type: text/plain\n\n";
$|=1; $|=0;                     # flush

my ($rc, $sth)=query($ENV{QUERY_STRING} || '1s', 'select burncpu(?)');

if( defined $rc ) {
  while( my $row=$sth->fetchrow_arrayref ) {
    print "@$row\n";
  }
} else {
  warn "query cancelled\n";
}