The document explains the concept of workflows as a modeling and automation framework for business processes, emphasizing its architecture based on states, actions, and conditions. It details the Perl-based workflow framework available on CPAN, which includes configurations, validators, and persisters, and outlines its history and future development goals. The author aims to maintain and enhance the project, seeking to improve documentation and extensibility while encouraging community contributions.

1. Illustration by xkcd used with permission: http://xkcd.com/518
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2. If you understand flowcharts
you will have absolutely no
problems understanding
workflows...
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3. If you understand flowcharts
you will have absolutely no
problems understanding
workflows...
let’s go
drink
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4. What is a workflow?
A modeling and automation concept for processes,
especially business related processes
Or: a way to emulate and automate processes using
reusable software components
Or: a simple state machine to handle your data flow on
a way suits can grasp
Or: perhaps an attempt at 4GL?
Or: plz read the wikipedia article
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5. So what is Workflow?
A not so light weight Perl framework available on
CPAN, which can be used to implement actual
workflows
Primarily focused on exploiting the best practice of
doing configuration over coding...
Well you will have to do “some” coding
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6. a workflow
consists of:
states
actions/transitions
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7. Workflows
Configurations are described in either XML or Perl - out of
the box
You can even write your own workflow configuration
handler. A tutorial explains how to write a YAML
configuration handler
Actions (Perl methods - this is where you code)
conditions (flow controllers)
validators (Perl methods - this is where you can write code)
Persisters
Several persister options currently available and Workflow
is DBI compatible
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8. <workflow>
<type>Ticket</type>
<description>This is the workflow for sample application Ticket</
description>
<persister>TestPersister</persister>
<state name="INITIAL">
<description>This is the state the workflow enters when
instantiated. It's like a 'state zero' but since we're
using names rather than IDs we cannot assume</description>
<!-- This action is accessible from this state by everyone -->
<action name="create issue"
resulting_state="CREATED"/>
</state>
<state name="CREATED">
<description>State of ticket after it has been created</description>
<action name="add comment" resulting_state="NOCHANGE">
<condition test="defined $context->{ticket}" />
</action>
<action name="edit issue"
resulting_state="IN_PROGRESS">
<condition name="IsWorker"/>
</action>
</state>
...
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9. <actions>
<action name="create issue"
class="App::Action::TicketCreate">
<description>Create a new issue</description>
<field name="subject"
label="Subject"
description="Subject of issue"
is_required="yes"/>
<field name="description"
label="Description"
description="Description of issue"
is_required="yes" />
<field name="creator"
label="Creator"
description="Name of user who is creating the ticket"
is_required="yes"
source_class="App::User"/>
<field name="type"
label="Type"
description="Type of ticket"
is_required="yes"
source_list="Bug,Feature,Improvement,Task"/>
<field name="due_date"
label="Due Date"
description="Date ticket is due (format: yyyy-mm-dd hh:mm)"/>
<validator name="DateValidator">
<arg>$due_date</arg>
</validator>
</action>
...
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10. <conditions>
<condition name="IsCreator"
class="App::Condition::IsCreator"/>
<condition name="IsWorker"
class="App::Condition::IsWorker"/>
<condition name="HasUserAndTicket"
class="App::Condition::HasUserAndTicket"/>
</conditions>
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11. <validators>
<validator name="DateValidator"
class="Workflow::Validator::MatchesDateFormat">
<description>Validator to ensure dates are proper</description>
<param name="date_format" value="%Y-%m-%d %H:%M"/>
</validator>
</validators>
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12. <persisters>
<persister name="TestPersister"
class="Workflow::Persister::DBI::ExtraData"
dsn="DBI:SQLite:dbname=db/ticket.db"
extra_table="workflow_ticket"
extra_data_field="ticket_id"/>
</persisters>
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13. Criticism
Workflow is not particularly Perl-ish, it
is actually quite low on black magic
Workflow is not as light weight as other
CPAN/Perl modules
You cannot just call Workflow->new and
be good to go
Yes - we are using patterns
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14. the Project
Small community with some nice reference
implementations (OpenXPKI etc.)
High acceptance rate of patches and contributions
Project Directives:
Stability, we have people using this in production
Extensibility, we want to make Workflow as
useful as possible
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15. some history
Initial implementation by Chris Winters
(releases from 0.01 to 0.17).
11th. of October 2004 - Initial release to CPAN
(0.10)
7th. of July 2006 Workflow handed over to me
(jonasbn) for ongoing maintenance and
development (my first release was 0.18)
19th. of September 2006 - Project set up at
SourceForge
Latest release 1.33, January 30th. 2010, yes we
release early and often - well as early and often
as it makes sense
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16. future stuff...
In pursuit of stability:
Aiming for higher test coverage, we have gone from: 63,4%
(0.17) to 76.8% (1.33)
Workflow does currently NOT work under Perl 5.12 and newer
In pursuit of extensibility:
Evaluation of issues in RT some of these are in regard to new
features and not bugs
In pursuit of a larger user base:
Aiming for more and better documentation and examples,
much of the documentation seems to reflect version 0.15 - so
updating and proof reading is required
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17. about me
Got interested in workflow after having worked with
Oracle Workflow (a free commercial product, well free
to the extent it does require Oracle)
Got excited when discovering Workflow on CPAN - all
free and all open source
Took over from Chris Winters
My own workflow projects stranded, but I still hope to
this day to find use of it at some point - for now I
only maintain Workflow...
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18. Resources
http://perl-workflow.sourceforge.net/
Friendly community
Documentation Wiki
low-traffic mailing list
Subversion repository
RT queue, currently only holding two items, where
one is an older patch not having been integrated yet
Irregular releases, my bad
jonasbn@cpan.org
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