Stem Version 0.11
=================
Fri Dec 1 03:50:58 EST 2006
* The Stem event loop is layered and can easily wrap other event
loops. Supported event loops include Event.pm, perl/tk and wxperl and
a pure Perl event Loop. See Stem::Event.pm and Stem::Event::EventPM.pm
for more. Other event loops that need wrapping include POE, Gtk and Qt.
* There is a pure Perl event Loop so Stem now runs on windows or on any
system where Event.pm isn't installed.
* Full support for SSL on all socket related objects and cells.
Converting from a plain socket to an SSL socket just requires adding
the SSL arguments to the Stem::Socket contruction. All Stem modules
that use sockets use Stem::Socket which in turn uses IO::Socket::SSL
(and that needs openssl). If that module is not installed, its test
will be skipped.
* There is a Stem::UDPMsg cell that provides a UDP socket client and/or
server.
* The new Stem::Cell::Flow module provides a way for Stem cells to
handle a mix of sync/async (local/remote) method calls. You can create
a logic flow with if/else/while command in a simple mini-language.
This allows a cell to do complex operations such as accessing a DB
(via Stem::DBI) or fetching web pages and mix that with local method
calls that crunch the data. Normally this would entail a complex state
machine or having each method know the next one to call but
Stem::Cell::Flow allows you to convert that to a much simpler logic
flow. See the test script t/cell/flow.t and the lib/Stem/Test/Flow.pm
module for more on this. It requires Parse::RecDescent to be installed
(the test will be skipped if it is not found).
* A bunch of new tests were added:
Event loops
Sockets (both with and without SSL)
Stem::Cell::Flow
* There is a brand new install based on Module::Build. A Makefile.PL is
provided but it is a wrapper around the Module::Build installer. Stem
can now be installed with CPAN.pm
* There is more pod (and more is needed). All contructor attributes are
now automatically updated to pod by the stem2pod utility. That script
also inserts pod templates for all methods. This will make it easier
to add pod and keep it up to date.
* Cleaned up the INSTALL, README and other top level documents.
* Many more changes than I have room to write in this file.
Stem Version 0.10
=================
Nov-11-2002
* The version number has been bumped to 0.10 because of the large number
of changes and the major improvements in reliability and speed.
* Renamed Stem::TtyMsg to Stem::Console. Now it doesn't need any
arguments to be initialized. A Stem envioronment variable can be set
which will disable it. All the configuration files and demo scripts
have been updated to use it. The old TtyMsg module has been deleted.
* Added Stem::Test::Echo.pm and Stem::Load::Driver.pm. They support
benchmarking of basic message passing in multiple modes.
* Stem::Msg now only accepts the string format of message
addresses. This speeds up message creation and simplifies message
handling and delivery.
* Stem::Class now supports attribute type checking and
conversion. Supported types include boolean, list, hash, LoL (and
friends), object and handle.
* Stem::Conf has better error reporting. The Cell name and class are now
printed with the error.
* Added the reply_type field to messages. This is used to make simple
state machines with messages (used in the work sequencing system).
* Stem::Portal has been improved and now use the Stem::Packet module to
handle its buffering.
* Added Stem::Packet and Stem::Codec::*. These modules support
serializing (marshalling) Stem data for use in pipes and files. The
codec to be used can be selected in the configuration file. This is
now used in Stem::Portal and all worker mode operations. Current codec
include Perl (Data::Dumper/eval), YAML, and Storable.
* Split Log.pm into Log.pm and Log/Entry.pm. Moved Stem::LogTail.pm to
Stem::Log::Tail.pm. Added Stem::Log::File which handles physical log
files including rotation and archiving.
* Added Stem::Trace.pm which gives modules a simple way to inject log
entries during program execution. It allows for creation of customized
Trace functions which can have defaults and different calling styles.
* Split Stem::Cell.pm into multiple files to make it easier to
maintain. These include Stem::Cell::Sequence.pm, Stem::Cell::Clone.pm,
Stem::Cell::Pipe.pm and Stem::Cell::Work.pm
* Added the Stem::DBI module which is a Stem message based front end to
DBI. This Cell can be configured with the all the SQL needed for your
application which is shared by all the Cells that use it. It can be
run in its own Stem Hub (process) thereby providing non-blocking
access to the DB from other Hubs. A farm of these proxies can be
created and managed by a WorkQueue Cell which will support parallel DB
access from one or more Hubs.
* Added work sequencing support in Stem::Cell. This allows any Cell to
call local or remote methods and to manage their flow control. This is
an interim version that will be superseded by a new mini-language that
will be easier to code and will support more complex flow
(e.g. if/else/while). This is a very powerful feature that simplifies
complex state operations to simple flow control statements.
* Added the Stem::WorkQueue module which allows a set of work request
messages to be distributed to a set of worker Cells. Modified
Stem::Cell to support a cell to request a new work message.
* Created worker mode where an object (or data structure) gets
sent to a Cell via a message. The Cell can then write the object to a
socket or process or crunch it. The Cell then gets back the object
(presumably modified) and sends it back to the originator of the work
request. This is done in Stem::Cell and used in Stem::Proc,
Stem::Sock::Msg and Stem::DBI.
* Created worker ready mode where a Cell can send out a message stating
it can receive a work message. Typically this will go to a WorkQueue
Cell. This message is sent out when the Cell starts up or after it
completes a previous work request.
* Added Stem::Boot.pm which will run a set of external programs and
monitor them. Their output can be logged and they can be
restarted. Other options (for each program) include setting the
initial directory and which host to run it on (via ssh if desired).
The set of programs and options are loaded via a configuration file
specific to this module.
* Added Stem::Inject.pm which has one method which will connect to
a Stem Hub and send it a single message. Then it will read back a
single message and return its data. This is meant to be used in Perl
programs that are not Stem driven and want to communicate with Stem
cells.
* Updated the Stem Cell cookbook with more examples. It now shows how to
create class and object cells and also how to create cloneable Cells.
Stem Version 0.06
=================
Feb-26-2002
* Stem is now released under the GPL. If you want to use Stem in a
product that will be sold, contact us about acquiring a commercial
license.
* A simple and easy to use installation script is now included. The
installation script allows you to have a Stem environment up and
running in a matter of minutes. Read the INSTALL document to learn how
to run this script.
* There is a new set of cookbook documents with examples. These show
you how to develop new Stem Cells.
* Complete documentation is now included for all demonstration
scripts included with Stem.
* Stem Message Addresses can now be in a string form as well as the hash
form. This simplifies creating addresses in Stem configurations. All
the installed configurations now use this format. See the Address
design notes for more on this.
* The Stem::Cell module has been added. It supports generic functionality for
Stem Cells, including cloning, asynchronous I/O, and pipes. It
currently is used by the Stem::Proc and Stem::SockMsg modules. All
future Cells that need those services can use this module.
* The modules Stem::Proc and Stem::SockMsg have been rewritten to use
Stem::Cell. They are much shorter and simpler now that the common
Cell functions are handled by Stem::Cell.
* A new module, Stem::Gather, has been added. It allows you to
synchronize multiple asynchronous events. It triggers a callback when
all of its required tokens have been 'gathered'.
* Bug fixes and general system improvements.