OpenACS Workflow Mark Aufflick pumptheory.com

This presentation Goal: Learn to use a workflow in a web application The OpenACS Workflow package Roles, Cases, Actions & States Defining a workflow Integrating a workflow with your app

Goal: Learn to use a workflow in a web application

The OpenACS Workflow package

Roles, Cases, Actions & States

Defining a workflow

Integrating a workflow with your app

A Brief History The original ACS Workflow package was designed using Petri Nets as the underlying formal model It’s design was very thorough, but the use of Petri Nets was overcomplicated and unnecessary in perhaps 95% of use cases In 2003 Lars Pind of Collaboraid didn’t use the existing workflow package because it was cumbersome and unfinished – even though he was the original author while working for ArsDigita!

The original ACS Workflow package was designed using Petri Nets as the underlying formal model

It’s design was very thorough, but the use of Petri Nets was overcomplicated and unnecessary in perhaps 95% of use cases

In 2003 Lars Pind of Collaboraid didn’t use the existing workflow package because it was cumbersome and unfinished – even though he was the original author while working for ArsDigita!

The new Workflow An analysis of common use cases showed that all common business workflows can be modeled with a simple Finite State Machine The new workflow package is a modular development framework, and allows multiple workflow models to be used Initially only FSMs are supported

An analysis of common use cases showed that all common business workflows can be modeled with a simple Finite State Machine

The new workflow package is a modular development framework, and allows multiple workflow models to be used

Initially only FSMs are supported

User Interface? Many workflow packages, including the original ACS Workflow, have funky UIs But – development is nearly always required So – the new workflow has been designed as a developer framework that allows the power of workflows to be easily incorporated into applications

Many workflow packages, including the original ACS Workflow, have funky UIs

But – development is nearly always required

So – the new workflow has been designed as a developer framework that allows the power of workflows to be easily incorporated into applications

Workflow Overview A workflow is a set of: Roles Actions States plus their relations A workflow is associated with an object type

A workflow is a set of:

Roles

Actions

States

plus their relations

A workflow is associated with an object type

Cases A workflow in action is a CASE A case revolves around a specific object A case holds information about: Current state Current assignments Activity log

A workflow in action is a CASE

A case revolves around a specific object

A case holds information about:

Current state

Current assignments

Activity log

Roles From our publishing example, roles might be: Author Editor Publisher Roles convey permission and responsibility Roles can be assigned by default and reassigned

From our publishing example, roles might be:

Author

Editor

Publisher

Roles convey permission and responsibility

Roles can be assigned by default and reassigned

Actions Which actions are available will depend on the current state Actions may change the state Actions can have side effects Allowed roles control who can perform what actions Assigned roles indicate who is responsible for the action A workflow has an initial action

Which actions are available will depend on the current state

Actions may change the state

Actions can have side effects

Allowed roles control who can perform what actions

Assigned roles indicate who is responsible for the action

A workflow has an initial action

States A workflow has a finite set of states From our bug tracker example: Open Resolved Closed A case will always be in exactly one state States contain almost no information

A workflow has a finite set of states

From our bug tracker example:

Open

Resolved

Closed

A case will always be in exactly one state

States contain almost no information

Defining a workflow Start by drawing a diagram -> your states, actions and roles set spec { contract { pretty_name "Contract" package_key "finance-contracts" object_type “finance_contract“ roles { } states { } actions { } } }

Start by drawing a diagram

-> your states, actions and roles

Defining a workflow: Roles roles { submitter { pretty_name "Submitter" call_backs { workflow.Role_DefaultAssignees_CreationUser } } assignee { pretty_name “Assignee” callbacks { bug-tracker.ComponentMaintainer bug-tracker.ProjectMaintainer workflow.Role_PickList_CurrentAssignees workflow.Role_AssigneeSubquery_RegisteredUsers } } }

Defining a workflow: States submitted { pretty_name "Submitted“ hide_fields { date_approval date_settlement } } approved { pretty_name "Approved" hide_fields { date_settlement } } declined { pretty_name "Declined" hide_fields { date_settlement } } settled { pretty_name "Settled" } discarded { pretty_name "Discarded" }

Defining a workflow: Actions (1) submit { pretty_name "Submit" pretty_past_tense "Submitted" new_state "submitted" initial_action_p t } comment { pretty_name "Comment" pretty_past_tense "Commented" allowed_roles { submitter } priviliges { read write } always_enabled_p t }

Defining a workflow: Actions (2) decline { pretty_name "Decline" pretty_past_tense "Declined" assigned_role "submitter" assigned_states { submitted } new_state "declined" privileges { write } edit_fields { date_approval } } approve { pretty_name "Approve" pretty_past_tense "Approved" assigned_role "submitter" assigned_states { submitted } new_state "approved" privileges { write } edit_fields { date_approval } }

Integrating With Your App's API Creating new objects workflow::case::new Fetching data workflow::case::get Editing objects workflow::case::action::execute see packages/bug-tracker/tcl/bug-procs.tcl

Creating new objects

workflow::case::new

Fetching data

workflow::case::get

Editing objects

workflow::case::action::execute

see packages/bug-tracker/tcl/bug-procs.tcl

Integrating with your App’s UI Bug Tracker demo… Use ad_form to build the form fields Workflow will give you: Action buttons ( workflow::case::get_available_actions) Role assignment ( workflow::case::role::add_assignee_widgets ) Case log ( workflow::case::get_activity_html ) See packages/bug-tracker/www/bug.tcl

Bug Tracker demo…

Use ad_form to build the form fields

Workflow will give you:

Action buttons ( workflow::case::get_available_actions)

Role assignment ( workflow::case::role::add_assignee_widgets )

Case log ( workflow::case::get_activity_html )

See packages/bug-tracker/www/bug.tcl

Integrating with your app’s queries For complex view-only listings, stats etc. Join with: workflow_cases workflow_fsm_states And others… See the bug-tracker index-postgresql.xql for an example

For complex view-only listings, stats etc.

Join with:

workflow_cases

workflow_fsm_states

And others…

See the bug-tracker index-postgresql.xql for an example

Service Contracts and Callback goodness What is a callback good for? Notifications Other side effects What is a service contract? ACS Service contract allows packages to define and register implementation of interfaces ACS Service contract provides mean to dispatch method calls on an interface implementation. Interface Discovery is available programmatically The Service Contract interface specification was inspired by WDSL, the interface specfication for web services.

What is a callback good for?

Notifications

Other side effects

What is a service contract?

ACS Service contract allows packages to define and register implementation of interfaces

ACS Service contract provides mean to dispatch method calls on an interface implementation.

Interface Discovery is available programmatically

The Service Contract interface specification was inspired by WDSL, the interface specfication for web services.

Package development details APM TCL callbacks: after-install (workflow::fsm::new_from_spec) before-uninstall ( workflow::delete ) before-upgrade after-instantiate ( workflow::fsm::clone ) before-uninstantiate( workflow::delete )

APM TCL callbacks:

after-install (workflow::fsm::new_from_spec)

before-uninstall ( workflow::delete )

before-upgrade

after-instantiate ( workflow::fsm::clone )

before-uninstantiate( workflow::delete )

References All references, slides and materials will be posted on the internet at: http://pumptheory.com/collaboration/open-acs/lectures/ OpenACS Workflow documentation http://www.collaboraid.biz/developer/workflow-spec

All references, slides and materials will be posted on the internet at:

http://pumptheory.com/collaboration/open-acs/lectures/

OpenACS Workflow documentation

http://www.collaboraid.biz/developer/workflow-spec