foo.sql

create schema if not exists utils;

create table utils.replaceable_now ( the_time timestamp with time zone );

CREATE  OR REPLACE FUNCTION replaceable_now() RETURNS timestamp with time zone AS $AA$
        SELECT coalesce((select the_time from utils.replaceable_now limit 1), now());
$AA$ LANGUAGE SQL STABLE;

/*
-- run in prod:
drop table utils.replaceable_now;

CREATE  OR REPLACE FUNCTION replaceable_now() RETURNS timestamp with time zone AS $AA$
        SELECT now()
$AA$ LANGUAGE SQL STABLE;

*/

utils.pl

sub set_relative_time {
    my ( $date, %conf ) = @_;
    my $schema = SFC->model( exists $conf{model} ? $conf{model} : 'DB' );
    $schema->storage->dbh_do(
        sub {
            shift;
            my $cn  = shift;
            my $res = $cn->do(qq{update utils.replaceable_now set the_time = '$date'::timestamp with time zone });

            if ( $res eq '0E0' ) {
                $cn->do(qq{insert into utils.replaceable_now ( the_time) values ( '$date'::timestamp with time zone )});
            }

        }
    );

}

sub epoch_to_datetime {
    my $epoch = shift;

    return DateTime->from_epoch( epoch => $epoch )->datetime;
}