#! perl -slw
use strict;
use threads;
use Thread::Queue;
use LWP::Simple;

our $N ||= 2;

my $Q = new Thread::Queue;

sub dbDump {
    my $pid;

    ## Add per-thread signal handlers closing over the $pid
    @SIG{ qw[TERM ALRM INT HUP] } = ( sub{ kill 9, $pid } ) x 4;

    my $opts = '-q --single-transaction --complete-insert';

    while( my $dbinfo = $Q->dequeue ) {
        my( $dbname ) = split ' ', $dbinfo, 1;
        my $outfile = $dbname . localtime() . '.dmp';
        my $pid = open my $cmd,
            "mysqldump $opts $dbinfo --results-file=$outfile |"
            or die $!;
    }
}

my @pool = map &async( \&dbDump ), 1 .. $N;

## Add main thread sig handlers to relay process signals to threads
@SIG{ qw[TERM ALRM INT HUP] } = ( sub{ $_->kill( 'TERM' ) for @pool } ) x 4;

for my $db (keys %{$db_ds}) {
    if (!@{$db_ds->{$db}} && !$opts{database}) {
        ### Our data stuctur says there is no native mysql tables.
        ### So we skip this database.
        next;
    }
    $dbh->do(qq{use $db});
    ### The table list in our data structure is empty.  The database
    ### option has been passed, so look them up.
    if (!@{$db_ds->{$db}}) {
        $queries{get_table_names}->execute();
        while (my $rec = $queries{get_table_names}->fetchrow_hashref()) {
            push @{$db_ds->{$db}}, $rec->{Name};
        }
        debug(qq{Got table list for $db\n});
    }

    ### This block makes sure we can actually access the tables.
    my @valid_tables;
    for my $table (@{$db_ds->{$db}}) {
        $queries{verify_table_name}->execute($table);
        if ($queries{verify_table_name}->rows()) {
            my ($rec) = $queries{verify_table_name}->fetchrow_array();
            push @valid_tables, $rec;
        } else {
            debug(qq{There was a problem finding database/table $db $table\n});
        }
    }
    $Q->enqueue( join ' ', $db, @valid_tables );
}

$Q->enqueue( (undef) x $N );

$_->join for @pool;