Workflow Yapceu2010

Illustration by xkcd used with permission: http://xkcd.com/518

1

If you understand flowcharts
you will have absolutely no
problems understanding
workflows...

2

If you understand flowcharts
you will have absolutely no
problems understanding
workflows...

let’s go
drink

2

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

3

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

4

a workflow
consists of:
states

actions/transitions

5

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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<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>


<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>
...

7

<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>
...

8

<conditions>
<condition name="IsCreator"
class="App::Condition::IsCreator"/>
<condition name="IsWorker"
class="App::Condition::IsWorker"/>
<condition name="HasUserAndTicket"
class="App::Condition::HasUserAndTicket"/>
</conditions>

9

<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>

10

<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>

11

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

12

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

13

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

14

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

15

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...

16

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

17

Workflow Yapceu2010

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