Greetings, monks. I ask your assistance.

I've been looking into updating some fairly old modules I have written, and, given some time to do so, look at redesigning them. And deciding to learn a better way to do things in general, decided to approach a easily solved problem, wondering what the better way is.

(Oh, I'm going to do a lot of things wrong. I'm pretty new to Moose, for one, and for another, this is design-related, so I'm taking shortcuts to demonstrate my thought processes.)

I have an application. It has a database connection. 
package MyApp::DBConnection
use Moose;
has dbh => {
    is => 'ro'
};
sub BUILD {
    #load the config from a config file, etc.
    #create the connection, set the handle.  Etc, etc.
}

1;

package MyApp;
use Moose;

has dbConnection (is => 'ro', isa => 'MyApp::DBConnection', default =>
+ sub { MyApp::DBConnection->new() });
1;

[download]
Good so far. Kinda. So long as MyApp is simple, this works. But then we add MyApp::DB::User. It needs the database handle to run some queries. 
package MyApp::DB::User;
use Moose;
has dbh => (is => 'ro', required => 1);

sub runQuery {
    return $shift->dbh->selectrow_array("sp_msforeachtable 'SELECT * F
+ROM \?'");
}

[download]
#someplace in MyApp
sub doSomethingWithUser {
    my $self = shift;
    my $user = MyApp::DB::User->new({dbh => $self->DBConnection->dbh})
+;
    1;
}

[download]
MyApp::User(s) are created at runtime. So, there's several things I can do:
* pass the connection around when I create the dependent objects.
      That's what I'm doing above. It works. It gets uglier when MyApp::DB::User needs to create MyApp::DB::User::SomethingElse, which also needs the database handle.
* create a DBConnection singleton.
     Again, it works. I could easily make the handle in MyApp::DBConnection a method that returns the same $dbh, for example, and call MyApp::DBConnection->dbh when I need it. I see a lot of .NET code that does this.
* ...Something else?
I was looking into dependency injection (with Bread::Board), but that doesn't seem to be right when I'm creating the objects at runtime.

Can anyone shed any light into modern (or post-modern) ways of handling this problem?

In reply to passing objects to dependancies by Anonymous Monk

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