I have collected my thoughts into a specification, available at this link<https://docs.google.com/document/d/1yeVV9Pf--BIE0GvkhVcPkF81vjxkzKcFtpcUlj7xZeQ/edit?pli=1> .
Comments invited and welcome. Thank you. On Tuesday, May 1, 2012 12:00:42 PM UTC-4, Ross Peoples wrote: > > In reference to: > https://groups.google.com/forum/#!searchin/web2py/workflow/web2py/osEmmtu9hlg/2MHi_ZCeMBMJ > > Has anyone done any work on this yet? I was thinking about making a > web2py-based workflow engine. > > I mentioned previously that I built one of these for an application I > wrote several years ago, but it was built specifically for that app. This > will be my first attempt at making a general-use workflow engine, so let me > know if you find any problems with my design: > > Make a contrib module that is initialized like the Auth module: > from gluon.contrib.workflow_engine import WorkflowEngine, Step > workflow_engine = WorkflowEngine() > workflow_engine.define_tables() > > > I will use the example that I know best, which is passing around a sales > order throughout a company's departments. This first example would define a > workflow template because every sales order will have the same workflow: > workflow_engine.add_template('Sales Order', > Step(group_id=2, hours=4), # Engineering gets 4 hours to complete > their step > Step(user_id=7, hours=0), # The engineering manager (user) has no > time limit > Step(group_id=3, hours=2), # Quality department gets 2 hours to > inspect the order > Step(group_id=8, hours=6.5), # Shipping department gets 6.5 hours to > ship order > ) > > > You would start this workflow like this: > workflow_id = workflow_engine.load_template('Sales Order', item_type= > 'document', item_id=1) > workflow_id = workflow_engine. > workflow_engine.start(workflow_id) > > > Optionally, a workflow can be created on the fly (if the workflow will > only be used once): > workflow_id = workflow_engine.create_workflow('One-time Workflow', > 'document', 1 # same as item_type and item_id used in load_template() > Step(group_id=2, hours=4) > Step(group_id=3, due_date=request.now + datetime.timedelta(days=1)) # > set time limit to an exact datetime > ) > > workflow_engine.start(workflow_id) # start the workflow we just created > > > We assume that we are going to associate this workflow with another > object. In this case, we will assume there is a table called "document" and > that the document we want to pass around has an id of 1. The "item_type" > argument allows you to pass around any type of database object. In this > case, we will call it the same thing as our table: "document". > > These are some common operations that could be done: > workflow_engine.active_workflows() # returns a list of all active > workflows > workflow_engine.active_workflows(user_id=1) # all active workflows for > the user_id > workflow_engine.active_workflows(user_id=1, include_groups=True) # same > as above, but includes groups the user is a member of > workflow_engine.active_workflows(group_id=2) # all active workflows for > the group_id > workflow_engine.late_workflows() # returns a list of all late/overdue > workflows > workflow_engine.step_complete(workflow_id, notes='General info about > completed task') # moves workflow to the next step > workflow_engine.step_reject(workflow_id, to_step=2, notes='Why step was > rejected') # moves workflow back to step 2 incase there was a problem > with one of the previously completed steps > > > Workflow triggers: > workflow_engine.before_start = function(workflow, step) > workflow_engine.after_start = function(workflow, step) > workflow_engine.before_step_complete = function(workflow, step) > workflow_engine.after_step_complete = function(workflow, step) > workflow_engine.before_step_reject = function(workflow, step) > workflow_engine.after_step_reject = function(workflow, step) > workflow_engine.before_finish = function(workflow, step) > workflow_engine.after_finish = function(workflow, step) > > > Finally, (and I MIGHT do this) since we are using time limits in hours, we > should set some time ranges where users are available. For example, if the > company is only open from 8 AM to 5 PM, you wouldn't want something to be > late at 7 PM. You would want to roll over the extra 2 hours so that it > becomes late at 10 AM the next business day. A list of time ranges would be > created, and a user would be assigned to one of the time ranges. This would > accommodate users in different time zones or with different "work" hours. > Again, this last part I MIGHT do if I have enough time. I've done it > before, but I'm sure you can imagine how complicated this part is. > > > So any questions, comments, improvements? Thanks! >
