fixlets on the workflow chapter stable
authorAurelien Campeas <aurelien.campeas@logilab.fr>
Mon, 05 Oct 2009 19:11:48 +0200
branchstable
changeset 3560 7d76775f965d
parent 3559 3e64534ffa87
child 3561 a267669f83f9
fixlets on the workflow chapter
cwctl.py
doc/book/en/development/datamodel/define-workflows.rst
--- a/cwctl.py	Mon Oct 05 18:45:40 2009 +0200
+++ b/cwctl.py	Mon Oct 05 19:11:48 2009 +0200
@@ -7,7 +7,7 @@
 import sys
 from os import remove, listdir, system, pathsep
 try:
-    from os import kill, getpgid
+    from os import kill, getpgi
 except ImportError:
     def kill(*args): pass
     def getpgid(): pass
@@ -414,9 +414,6 @@
 the --force option."
             raise ExecutionError(msg % (appid, pidf))
         helper.start_server(config, debug)
-        if not debug:
-            # in debug mode, we reach this point once the instance is stopped...
-            print 'instance %s %s' % (appid, self.actionverb)
 
 
 class StopInstanceCommand(InstanceCommand):
--- a/doc/book/en/development/datamodel/define-workflows.rst	Mon Oct 05 18:45:40 2009 +0200
+++ b/doc/book/en/development/datamodel/define-workflows.rst	Mon Oct 05 19:11:48 2009 +0200
@@ -8,17 +8,17 @@
 
 A workflow describes how certain entities have to evolve between
 different states. Hence we have a set of states, and a "transition graph",
-i.e. a list of possible transitions from one state to another state.
+i.e. a set of possible transitions from one state to another state.
 
 We will define a simple workflow for a blog, with only the following
 two states: `submitted` and `published`. So first, we create a simple
-*CubicWeb* in ten minutes (see :ref:`BlogFiveMinutes`).
+*CubicWeb* instance in ten minutes (see :ref:`BlogFiveMinutes`).
 
 Set-up a workflow
 -----------------
 
 We want to create a workflow to control the quality of the BlogEntry
-submitted on your instance. When a BlogEntry is created by a user
+submitted on the instance. When a BlogEntry is created by a user
 its state should be `submitted`. To be visible to all, it has to
 be in the state `published`. To move it from `submitted` to `published`,
 we need a transition that we can call `approve_blogentry`.
@@ -27,16 +27,16 @@
 So we have to define a group of users, `moderators`, and
 this group will have appropriate permissions to publish a BlogEntry.
 
-There are two ways to create a workflow: from the user interface,
-or by defining it in ``migration/postcreate.py``.
-This script is executed each time a new ``cubicweb-ctl db-init`` is done.
-We strongly recommend to create the workflow in ``migration/postcreate.py``
-and we will now show you how. Read `Under the hood`_ to understand why.
+There are two ways to create a workflow: from the user interface, or
+by defining it in ``migration/postcreate.py``. This script is executed
+each time a new ``cubicweb-ctl db-init`` is done.  We strongly
+recommend to create the workflow in ``migration/postcreate.py`` and we
+will now show you how. Read `Two bits of warning`_ to understand why.
 
-The state of a entity is managed by the `in_state` attribute which can be added to you entity schema by two ways:
+The state of an entity is managed by the `in_state` attribute which
+can be added to your entity schema by inheriting from
+`cubicweb.schema.WorkflowableEntityType`.
 
-* direct inheritance by subclassing your class from `cubicweb.schema.WorkflowableEntityType`
-* by delegation using `cubicweb.schema.make_worflowable` (usable as a decorator)
 
 About our example of BlogEntry, we must have:
 
@@ -44,7 +44,7 @@
 
   from cubicweb.schema import WorkflowableEntityType
 
-  class BlogEntry(EntityType, WorkflowableEntityType):
+  class BlogEntry(WorkflowableEntityType):
       ...
 
 
@@ -53,10 +53,14 @@
 
 The ``postcreate.py`` script is executed in a special environment, adding
 several *CubicWeb* primitives that can be used.
+
 They are all defined in the ``class ServerMigrationHelper``.
 We will only discuss the methods we use to create a workflow in this example.
 
-To define our workflow for BlogDemo, please add the following lines
+A workflow is a collection of entities of type ``State`` and of type
+``Transition`` which are standard *CubicWeb* entity types.
+
+To define a workflow for BlogDemo, please add the following lines
 to ``migration/postcreate.py``:
 
 .. sourcecode:: python
@@ -69,25 +73,35 @@
 
 .. sourcecode:: python
 
-  wf = add_workflow(u'your workflow description', 'BlogEntry')
+  wf = add_workflow(u'blog publication workflow', 'BlogEntry')
 
-At first, instanciate a new workflow object with a gentle description and the concerned entity types (this one can be a tuple for multiple value).
+At first, instanciate a new workflow object with a gentle description
+and the concerned entity types (this one can be a tuple for multiple
+value).
 
 .. sourcecode:: python
 
   submitted = wf.add_state(_('submitted'), initial=True)
   published = wf.add_state(_('published'))
 
-``add_state`` expects as first argument the name of the state you want to create and an optional argument to say if it is supposed to be the initial state of the entity type.
+This will create two entities of type ``State``, one with name
+'submitted', and the other with name 'published'.
+
+``add_state`` expects as first argument the name of the state you want
+to create and an optional argument to say if it is supposed to be the
+initial state of the entity type.
 
 .. sourcecode:: python
 
   wf.add_transition(_('approve_blogentry'), (submitted,), published, ('moderators', 'managers'),)
 
+This will create an entity of type ``Transition`` with name
+`approve_blogentry` which will be linked to the ``State`` entities
+created before.
 
 ``add_transition`` expects
 
-  * as the first argument the name of the transition
+  * as the first argument: the name of the transition
   * then the list of states on which the transition can be triggered,
   * the target state of the transition,
   * and the permissions
@@ -102,10 +116,11 @@
   Do not forget to add the `_()` in front of all states and transitions names while creating
   a workflow so that they will be identified by the i18n catalog scripts.
 
-In addition to the user group conditions which the user needs to belong to one of those, we could have added a RQL condition.
-In this case, the user can only perform the action if the two conditions are satisfied.
+In addition to the user groups (one of which the user needs to belong
+to), we could have added a RQL condition.  In this case, the user can
+only perform the action if the two conditions are satisfied.
 
-If we use a RQL condition on a transition, we can use the following variables:
+If we use an RQL condition on a transition, we can use the following variables:
 
 * `%(eid)s`, object's eid
 * `%(ueid)s`, user executing the query eid
@@ -114,38 +129,30 @@
 
 .. image:: ../../images/03-transitions-view.en.png
 
-You can notice that in the action box of a BlogEntry, the state
-is now listed as well as the possible transitions for the current state defined by the workflow.
+You can notice that in the action box of a BlogEntry, the state is now
+listed as well as the possible transitions for the current state
+defined by the workflow.
+
 The transitions will only be displayed for users having the right permissions.
 In our example, the transition `approve_blogentry` will only be displayed
 for the users belonging to the group `moderators` or `managers`.
 
 
-Under the hood
-~~~~~~~~~~~~~~
-
-A workflow is a collection of entities of type ``State`` and of type ``Transition``
-which are standard *CubicWeb* entity types.
-
-For instance, the preceding lines:
-
-.. sourcecode:: python
-
-  submitted = wf.add_state(_('submitted'), initial=True)
-  published = wf.add_state(_('published'))
+Two bits of warning
+~~~~~~~~~~~~~~~~~~~
 
-will create two entities of type ``State``, one with name 'submitted', and the other
-with name 'published'. Whereas:
-
-.. sourcecode:: python
-
-  wf.add_transition(_('approve_blogentry'), (submitted,), published, ('moderators', 'managers'),)
+We could perfectly use the administration interface to do these
+operations. It is a convenient thing to do at times (when doing
+development, to quick-check things). But it is not recommended beyond
+that because it is a bit complicated to do it right and it will be
+only local to your instance (or, said a bit differently, such a
+workflow only exists in an instance database). Furthermore, you cannot
+write unit tests against deployed instances, and experience shows it
+is mandatory to have tests for any mildly complicated workflow
+setup.
 
-will create an entity of type ``Transition`` with name `approve_blogentry` which will
-be linked to the ``State`` entities created before.
-As a consequence, we could use the administration interface to do these operations. But it is not recommended because it will be uselessly complicated and will be only local to your instance.
-
-Indeed, if you create the states and transitions through the user interface, next time you initialize the database you will have to re-create all the entities.
-The user interface should only be a reference for you to view the states and transitions, but is not the appropriate interface to define your application workflow.
-
-
+Indeed, if you create the states and transitions through the user
+interface, next time you initialize the database you will have to
+re-create all the workflow entities. The user interface should only be
+a reference for you to view the states and transitions, but is not the
+appropriate interface to define your application workflow.