dbd::gofer::transport::stream(3) [osx man page]

DBD::Gofer::Transport::stream(3)			User Contributed Perl Documentation			  DBD::Gofer::Transport::stream(3)

NAME

       DBD::Gofer::Transport::stream - DBD::Gofer transport for stdio streaming

SYNOPSIS

	 DBI->connect('dbi:Gofer:transport=stream;url=ssh:username@host.example.com;dsn=dbi:...',...)

       or, enable by setting the DBI_AUTOPROXY environment variable:

	 export DBI_AUTOPROXY='dbi:Gofer:transport=stream;url=ssh:username@host.example.com'

DESCRIPTION

       Without the "url=" parameter it launches a subprocess as

	 perl -MDBI::Gofer::Transport::stream -e run_stdio_hex

       and feeds requests into it and reads responses from it. But that's not very useful.

       With a "url=ssh:username@host.example.com" parameter it uses ssh to launch the subprocess on a remote system. That's much more useful!

       It gives you secure remote access to DBI databases on any system you can login to.  Using ssh also gives you optional compression and many
       other features (see the ssh manual for how to configure that and many other options via ~/.ssh/config file).

       The actual command invoked is something like:

	 ssh -xq ssh:username@host.example.com bash -c $setup $run

       where $run is the command shown above, and $command is

	 . .bash_profile 2>/dev/null || . .bash_login 2>/dev/null || . .profile 2>/dev/null; exec "$@"

       which is trying (in a limited and fairly unportable way) to setup the environment (PATH, PERL5LIB etc) as it would be if you had logged in
       to that system.

       The ""perl"" used in the command will default to the value of $^X when not using ssh.  On most systems that's the full path to the perl
       that's currently executing.

PERSISTENCE

       Currently gofer stream connections persist (remain connected) after all database handles have been disconnected. This makes later
       connections in the same process very fast.

       Currently up to 5 different gofer stream connections (based on url) can persist.  If more than 5 are in the cache when a new connection is
       made then the cache is cleared before adding the new connection. Simple but effective.

TO DO

       Document go_perl attribute

       Automatically reconnect (within reason) if there's a transport error.

       Decide on default for persistent connection - on or off? limits? ttl?

AUTHOR

       Tim Bunce, <http://www.tim.bunce.name>

LICENCE AND COPYRIGHT

       Copyright (c) 2007, Tim Bunce, Ireland. All rights reserved.

       This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlartistic.

SEE ALSO

       DBD::Gofer::Transport::Base

       DBD::Gofer

perl v5.16.2							    2010-12-21					  DBD::Gofer::Transport::stream(3)

DBD::Gofer::Transport::corostream(3)			User Contributed Perl Documentation		      DBD::Gofer::Transport::corostream(3)

NAME

       DBD::Gofer::Transport::corostream - Async DBD::Gofer stream transport using Coro and AnyEvent

SYNOPSIS

	  DBI_AUTOPROXY="dbi:Gofer:transport=corostream" perl some-perl-script-using-dbi.pl

       or

	  $dsn = ...; # the DSN for the driver and database you want to use
	  $dbh = DBI->connect("dbi:Gofer:transport=corostream;dsn=$dsn", ...);

DESCRIPTION

       The BIG WIN from using Coro is that it enables the use of existing DBI frameworks like DBIx::Class.

KNOWN ISSUES AND LIMITATIONS

	 - Uses Coro::Select so alters CORE::select globally
	   Parent class probably needs refactoring to enable a more encapsulated approach.

	 - Doesn't prevent multiple concurrent requests
	   Probably just needs a per-connection semaphore

	 - Coro has many caveats. Caveat emptor.

STATUS

       THIS IS CURRENTLY JUST A PROOF-OF-CONCEPT IMPLEMENTATION FOR EXPERIMENTATION.

       Please note that I have no plans to develop this code further myself.  I'd very much welcome contributions. Interested? Let me know!

AUTHOR

       Tim Bunce, <http://www.tim.bunce.name>

LICENCE AND COPYRIGHT

       Copyright (c) 2010, Tim Bunce, Ireland. All rights reserved.

       This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself. See perlartistic.

SEE ALSO

       DBD::Gofer::Transport::stream

       DBD::Gofer

APPENDIX

       Example code:

	   #!perl

	   use strict;
	   use warnings;
	   use Time::HiRes qw(time);

	   BEGIN { $ENV{PERL_ANYEVENT_STRICT} = 1; $ENV{PERL_ANYEVENT_VERBOSE} = 1; }

	   use AnyEvent;

	   BEGIN { $ENV{DBI_TRACE} = 0; $ENV{DBI_GOFER_TRACE} = 0; $ENV{DBD_GOFER_TRACE} = 0; };

	   use DBI;

	   $ENV{DBI_AUTOPROXY} = 'dbi:Gofer:transport=corostream';

	   my $ticker = AnyEvent->timer( after => 0, interval => 0.1, cb => sub {
	       warn sprintf "-tick- %.2f
", time
	   } );

	   warn "connecting...
";
	   my $dbh = DBI->connect("dbi:NullP:");
	   warn "...connected
";

	   for (1..3) {
	       warn "entering DBI...
";
	       $dbh->do("sleep 0.3"); # pseudo-sql understood by the DBD::NullP driver
	       warn "...returned
";
	   }

	   warn "done.";

       Example output:

	   $ perl corogofer.pl
	   connecting...
	   -tick- 1293631437.14
	   -tick- 1293631437.14
	   ...connected
	   entering DBI...
	   -tick- 1293631437.25
	   -tick- 1293631437.35
	   -tick- 1293631437.45
	   -tick- 1293631437.55
	   ...returned
	   entering DBI...
	   -tick- 1293631437.66
	   -tick- 1293631437.76
	   -tick- 1293631437.86
	   ...returned
	   entering DBI...
	   -tick- 1293631437.96
	   -tick- 1293631438.06
	   -tick- 1293631438.16
	   ...returned
	   done. at corogofer.pl line 39.

       You can see that the timer callback is firing while the code 'waits' inside the do() method for the response from the database. Normally
       that would block.

perl v5.16.2							    2010-12-29				      DBD::Gofer::Transport::corostream(3)