08e6ed7392
We should use ugettext_lazy to let users in different languages get correct translation.Though in views or similar places we can use ugettext with no problems, we should make code style consistent. This also fix the issues that the django proxy objects appear on the launching instance page instead of translated strings. Now the translated quota strings are handled correctly. Fixes: bug #1178722 Change-Id: I76f0d31e6546d70e5ece7e86a06f7eefd04861d2
846 lines
31 KiB
Python
846 lines
31 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright 2012 Nebula, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import copy
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import inspect
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import logging
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from django import forms
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from django import template
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from django.core import urlresolvers
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from django.template.defaultfilters import slugify
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from django.utils.encoding import force_unicode
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from django.utils.importlib import import_module
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from django.utils.translation import ugettext_lazy as _
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from django.template.defaultfilters import linebreaks, safe
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from django.forms.forms import NON_FIELD_ERRORS
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from horizon import base
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from horizon import exceptions
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from horizon.templatetags.horizon import has_permissions
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from horizon.utils import html
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LOG = logging.getLogger(__name__)
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class WorkflowContext(dict):
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def __init__(self, workflow, *args, **kwargs):
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super(WorkflowContext, self).__init__(*args, **kwargs)
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self._workflow = workflow
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def __setitem__(self, key, val):
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super(WorkflowContext, self).__setitem__(key, val)
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return self._workflow._trigger_handlers(key)
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def __delitem__(self, key):
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return self.__setitem__(key, None)
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def set(self, key, val):
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return self.__setitem__(key, val)
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def unset(self, key):
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return self.__delitem__(key)
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class ActionMetaclass(forms.forms.DeclarativeFieldsMetaclass):
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def __new__(mcs, name, bases, attrs):
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# Pop Meta for later processing
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opts = attrs.pop("Meta", None)
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# Create our new class
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cls = super(ActionMetaclass, mcs).__new__(mcs, name, bases, attrs)
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# Process options from Meta
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cls.name = getattr(opts, "name", name)
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cls.slug = getattr(opts, "slug", slugify(name))
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cls.permissions = getattr(opts, "permissions", ())
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cls.progress_message = getattr(opts,
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"progress_message",
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_("Processing..."))
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cls.help_text = getattr(opts, "help_text", "")
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cls.help_text_template = getattr(opts, "help_text_template", None)
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return cls
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class Action(forms.Form):
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"""
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An ``Action`` represents an atomic logical interaction you can have with
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the system. This is easier to understand with a conceptual example: in the
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context of a "launch instance" workflow, actions would include "naming
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the instance", "selecting an image", and ultimately "launching the
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instance".
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Because ``Actions`` are always interactive, they always provide form
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controls, and thus inherit from Django's ``Form`` class. However, they
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have some additional intelligence added to them:
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* ``Actions`` are aware of the permissions required to complete them.
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* ``Actions`` have a meta-level concept of "help text" which is meant to be
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displayed in such a way as to give context to the action regardless of
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where the action is presented in a site or workflow.
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* ``Actions`` understand how to handle their inputs and produce outputs,
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much like :class:`~horizon.forms.SelfHandlingForm` does now.
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``Action`` classes may define the following attributes in a ``Meta``
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class within them:
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.. attribute:: name
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The verbose name for this action. Defaults to the name of the class.
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.. attribute:: slug
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A semi-unique slug for this action. Defaults to the "slugified" name
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of the class.
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.. attribute:: permissions
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A list of permission names which this action requires in order to be
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completed. Defaults to an empty list (``[]``).
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.. attribute:: help_text
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A string of simple help text to be displayed alongside the Action's
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fields.
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.. attribute:: help_text_template
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A path to a template which contains more complex help text to be
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displayed alongside the Action's fields. In conjunction with
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:meth:`~horizon.workflows.Action.get_help_text` method you can
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customize your help text template to display practically anything.
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"""
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__metaclass__ = ActionMetaclass
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def __init__(self, request, context, *args, **kwargs):
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if request.method == "POST":
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super(Action, self).__init__(request.POST, initial=context)
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else:
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super(Action, self).__init__(initial=context)
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if not hasattr(self, "handle"):
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raise AttributeError("The action %s must define a handle method."
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% self.__class__.__name__)
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self.request = request
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self._populate_choices(request, context)
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def __unicode__(self):
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return force_unicode(self.name)
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def __repr__(self):
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return "<%s: %s>" % (self.__class__.__name__, self.slug)
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def _populate_choices(self, request, context):
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for field_name, bound_field in self.fields.items():
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meth = getattr(self, "populate_%s_choices" % field_name, None)
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if meth is not None and callable(meth):
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bound_field.choices = meth(request, context)
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def get_help_text(self, extra_context=None):
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""" Returns the help text for this step. """
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text = ""
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extra_context = extra_context or {}
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if self.help_text_template:
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tmpl = template.loader.get_template(self.help_text_template)
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context = template.RequestContext(self.request, extra_context)
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text += tmpl.render(context)
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else:
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text += linebreaks(force_unicode(self.help_text))
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return safe(text)
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def add_error(self, message):
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"""
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Adds an error to the Action's Step based on API issues.
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"""
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self._get_errors()[NON_FIELD_ERRORS] = self.error_class([message])
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def handle(self, request, context):
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"""
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Handles any requisite processing for this action. The method should
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return either ``None`` or a dictionary of data to be passed to
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:meth:`~horizon.workflows.Step.contribute`.
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Returns ``None`` by default, effectively making it a no-op.
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"""
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return None
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class Step(object):
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"""
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A step is a wrapper around an action which defines it's context in a
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workflow. It knows about details such as:
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* The workflow's context data (data passed from step to step).
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* The data which must be present in the context to begin this step (the
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step's dependencies).
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* The keys which will be added to the context data upon completion of the
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step.
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* The connections between this step's fields and changes in the context
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data (e.g. if that piece of data changes, what needs to be updated in
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this step).
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A ``Step`` class has the following attributes:
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.. attribute:: action
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The :class:`~horizon.workflows.Action` class which this step wraps.
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.. attribute:: depends_on
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A list of context data keys which this step requires in order to
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begin interaction.
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.. attribute:: contributes
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A list of keys which this step will contribute to the workflow's
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context data. Optional keys should still be listed, even if their
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values may be set to ``None``.
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.. attribute:: connections
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A dictionary which maps context data key names to lists of callbacks.
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The callbacks may be functions, dotted python paths to functions
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which may be imported, or dotted strings beginning with ``"self"``
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to indicate methods on the current ``Step`` instance.
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.. attribute:: before
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Another ``Step`` class. This optional attribute is used to provide
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control over workflow ordering when steps are dynamically added to
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workflows. The workflow mechanism will attempt to place the current
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step before the step specified in the attribute.
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.. attribute:: after
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Another ``Step`` class. This attribute has the same purpose as
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:meth:`~horizon.workflows.Step.before` except that it will instead
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attempt to place the current step after the given step.
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.. attribute:: help_text
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A string of simple help text which will be prepended to the ``Action``
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class' help text if desired.
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.. attribute:: template_name
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A path to a template which will be used to render this step. In
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general the default common template should be used. Default:
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``"horizon/common/_workflow_step.html"``.
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.. attribute:: has_errors
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A boolean value which indicates whether or not this step has any
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errors on the action within it or in the scope of the workflow. This
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attribute will only accurately reflect this status after validation
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has occurred.
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.. attribute:: slug
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Inherited from the ``Action`` class.
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.. attribute:: name
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Inherited from the ``Action`` class.
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.. attribute:: permissions
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Inherited from the ``Action`` class.
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"""
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action_class = None
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depends_on = ()
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contributes = ()
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connections = None
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before = None
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after = None
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help_text = ""
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template_name = "horizon/common/_workflow_step.html"
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def __repr__(self):
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return "<%s: %s>" % (self.__class__.__name__, self.slug)
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def __unicode__(self):
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return force_unicode(self.name)
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def __init__(self, workflow):
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super(Step, self).__init__()
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self.workflow = workflow
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cls = self.__class__.__name__
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if not (self.action_class and issubclass(self.action_class, Action)):
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raise AttributeError("You must specify an action for %s." % cls)
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self.slug = self.action_class.slug
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self.name = self.action_class.name
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self.permissions = self.action_class.permissions
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self.has_errors = False
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self._handlers = {}
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if self.connections is None:
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# We want a dict, but don't want to declare a mutable type on the
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# class directly.
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self.connections = {}
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# Gather our connection handlers and make sure they exist.
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for key, handlers in self.connections.items():
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self._handlers[key] = []
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# TODO(gabriel): This is a poor substitute for broader handling
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if not isinstance(handlers, (list, tuple)):
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raise TypeError("The connection handlers for %s must be a "
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"list or tuple." % cls)
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for possible_handler in handlers:
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if callable(possible_handler):
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# If it's callable we know the function exists and is valid
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self._handlers[key].append(possible_handler)
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continue
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elif not isinstance(possible_handler, basestring):
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return TypeError("Connection handlers must be either "
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"callables or strings.")
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bits = possible_handler.split(".")
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if bits[0] == "self":
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root = self
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for bit in bits[1:]:
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try:
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root = getattr(root, bit)
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except AttributeError:
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raise AttributeError("The connection handler %s "
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"could not be found on %s."
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% (possible_handler, cls))
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handler = root
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elif len(bits) == 1:
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# Import by name from local module not supported
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raise ValueError("Importing a local function as a string "
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"is not supported for the connection "
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"handler %s on %s."
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% (possible_handler, cls))
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else:
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# Try a general import
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module_name = ".".join(bits[:-1])
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try:
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mod = import_module(module_name)
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handler = getattr(mod, bits[-1])
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except ImportError:
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raise ImportError("Could not import %s from the "
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"module %s as a connection "
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"handler on %s."
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% (bits[-1], module_name, cls))
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except AttributeError:
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raise AttributeError("Could not import %s from the "
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"module %s as a connection "
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"handler on %s."
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% (bits[-1], module_name, cls))
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self._handlers[key].append(handler)
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@property
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def action(self):
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if not getattr(self, "_action", None):
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try:
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# Hook in the action context customization.
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workflow_context = dict(self.workflow.context)
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context = self.prepare_action_context(self.workflow.request,
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workflow_context)
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self._action = self.action_class(self.workflow.request,
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context)
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except:
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LOG.exception("Problem instantiating action class.")
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raise
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return self._action
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def prepare_action_context(self, request, context):
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"""
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Allows for customization of how the workflow context is passed to the
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action; this is the reverse of what "contribute" does to make the
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action outputs sane for the workflow. Changes to the context are not
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saved globally here. They are localized to the action.
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Simply returns the unaltered context by default.
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"""
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return context
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def get_id(self):
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""" Returns the ID for this step. Suitable for use in HTML markup. """
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return "%s__%s" % (self.workflow.slug, self.slug)
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def _verify_contributions(self, context):
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for key in self.contributes:
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# Make sure we don't skip steps based on weird behavior of
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# POST query dicts.
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field = self.action.fields.get(key, None)
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if field and field.required and not context.get(key):
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context.pop(key, None)
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failed_to_contribute = set(self.contributes)
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failed_to_contribute -= set(context.keys())
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if failed_to_contribute:
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raise exceptions.WorkflowError("The following expected data was "
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"not added to the workflow context "
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"by the step %s: %s."
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% (self.__class__,
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failed_to_contribute))
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return True
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def contribute(self, data, context):
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"""
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Adds the data listed in ``contributes`` to the workflow's shared
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context. By default, the context is simply updated with all the data
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returned by the action.
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Note that even if the value of one of the ``contributes`` keys is
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not present (e.g. optional) the key should still be added to the
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context with a value of ``None``.
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"""
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if data:
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for key in self.contributes:
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context[key] = data.get(key, None)
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return context
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def render(self):
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""" Renders the step. """
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step_template = template.loader.get_template(self.template_name)
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extra_context = {"form": self.action,
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"step": self}
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context = template.RequestContext(self.workflow.request, extra_context)
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return step_template.render(context)
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def get_help_text(self):
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""" Returns the help text for this step. """
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text = linebreaks(force_unicode(self.help_text))
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text += self.action.get_help_text()
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return safe(text)
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def add_error(self, message):
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"""
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Adds an error to the Step based on API issues.
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"""
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self.action.add_error(message)
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class WorkflowMetaclass(type):
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def __new__(mcs, name, bases, attrs):
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super(WorkflowMetaclass, mcs).__new__(mcs, name, bases, attrs)
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attrs["_cls_registry"] = set([])
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return type.__new__(mcs, name, bases, attrs)
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class UpdateMembersStep(Step):
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"""A step that allows a user to add/remove members from a group.
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.. attribute:: show_roles
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Set to False to disable the display of the roles dropdown.
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.. attribute:: available_list_title
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The title used for the available list column.
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.. attribute:: members_list_title
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The title used for the members list column.
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.. attribute:: no_available_text
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The placeholder text used when the available list is empty.
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.. attribute:: no_members_text
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The placeholder text used when the members list is empty.
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"""
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template_name = "horizon/common/_workflow_step_update_members.html"
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show_roles = True
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available_list_title = _("All available")
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members_list_title = _("Members")
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no_available_text = _("None available.")
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no_members_text = _("No members.")
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class Workflow(html.HTMLElement):
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"""
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A Workflow is a collection of Steps. It's interface is very
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straightforward, but it is responsible for handling some very
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important tasks such as:
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* Handling the injection, removal, and ordering of arbitrary steps.
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* Determining if the workflow can be completed by a given user at runtime
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based on all available information.
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* Dispatching connections between steps to ensure that when context data
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changes all the applicable callback functions are executed.
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* Verifying/validating the overall data integrity and subsequently
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triggering the final method to complete the workflow.
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The ``Workflow`` class has the following attributes:
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.. attribute:: name
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The verbose name for this workflow which will be displayed to the user.
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Defaults to the class name.
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.. attribute:: slug
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The unique slug for this workflow. Required.
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.. attribute:: steps
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Read-only access to the final ordered set of step instances for
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this workflow.
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.. attribute:: default_steps
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A list of :class:`~horizon.workflows.Step` classes which serve as the
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starting point for this workflow's ordered steps. Defaults to an empty
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list (``[]``).
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.. attribute:: finalize_button_name
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The name which will appear on the submit button for the workflow's
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form. Defaults to ``"Save"``.
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.. attribute:: success_message
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A string which will be displayed to the user upon successful completion
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of the workflow. Defaults to
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``"{{ workflow.name }} completed successfully."``
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.. attribute:: failure_message
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A string which will be displayed to the user upon failure to complete
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the workflow. Defaults to ``"{{ workflow.name }} did not complete."``
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.. attribute:: depends_on
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A roll-up list of all the ``depends_on`` values compiled from the
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workflow's steps.
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.. attribute:: contributions
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A roll-up list of all the ``contributes`` values compiled from the
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workflow's steps.
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.. attribute:: template_name
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Path to the template which should be used to render this workflow.
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In general the default common template should be used. Default:
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``"horizon/common/_workflow.html"``.
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.. attribute:: entry_point
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The slug of the step which should initially be active when the
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workflow is rendered. This can be passed in upon initialization of
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the workflow, or set anytime after initialization but before calling
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either ``get_entry_point`` or ``render``.
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.. attribute:: redirect_param_name
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The name of a parameter used for tracking the URL to redirect to upon
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completion of the workflow. Defaults to ``"next"``.
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.. attribute:: object
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The object (if any) which this workflow relates to. In the case of
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a workflow which creates a new resource the object would be the created
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resource after the relevant creation steps have been undertaken. In
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the case of a workflow which updates a resource it would be the
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resource being updated after it has been retrieved.
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"""
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__metaclass__ = WorkflowMetaclass
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slug = None
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default_steps = ()
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template_name = "horizon/common/_workflow.html"
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finalize_button_name = _("Save")
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success_message = _("%s completed successfully.")
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failure_message = _("%s did not complete.")
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redirect_param_name = "next"
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_registerable_class = Step
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def __unicode__(self):
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return self.name
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def __repr__(self):
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return "<%s: %s>" % (self.__class__.__name__, self.slug)
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def __init__(self, request=None, context_seed=None, entry_point=None,
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*args, **kwargs):
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super(Workflow, self).__init__(*args, **kwargs)
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if self.slug is None:
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raise AttributeError("The workflow %s must have a slug."
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% self.__class__.__name__)
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self.name = getattr(self, "name", self.__class__.__name__)
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self.request = request
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self.depends_on = set([])
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self.contributions = set([])
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self.entry_point = entry_point
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self.object = None
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# Put together our steps in order. Note that we pre-register
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# non-default steps so that we can identify them and subsequently
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# insert them in order correctly.
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self._registry = dict([(step_class, step_class(self)) for step_class
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in self.__class__._cls_registry
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if step_class not in self.default_steps])
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self._gather_steps()
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# Determine all the context data we need to end up with.
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for step in self.steps:
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self.depends_on = self.depends_on | set(step.depends_on)
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self.contributions = self.contributions | set(step.contributes)
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# Initialize our context. For ease we can preseed it with a
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# regular dictionary. This should happen after steps have been
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# registered and ordered.
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self.context = WorkflowContext(self)
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context_seed = context_seed or {}
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clean_seed = dict([(key, val)
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for key, val in context_seed.items()
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if key in self.contributions | self.depends_on])
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self.context_seed = clean_seed
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self.context.update(clean_seed)
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if request and request.method == "POST":
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for step in self.steps:
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valid = step.action.is_valid()
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# Be sure to use the CLEANED data if the workflow is valid.
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if valid:
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data = step.action.cleaned_data
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else:
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data = request.POST
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self.context = step.contribute(data, self.context)
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@property
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def steps(self):
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if getattr(self, "_ordered_steps", None) is None:
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self._gather_steps()
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return self._ordered_steps
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def get_step(self, slug):
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""" Returns the instantiated step matching the given slug. """
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for step in self.steps:
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if step.slug == slug:
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return step
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def _gather_steps(self):
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ordered_step_classes = self._order_steps()
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for default_step in self.default_steps:
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self.register(default_step)
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self._registry[default_step] = default_step(self)
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self._ordered_steps = [self._registry[step_class]
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for step_class in ordered_step_classes
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if has_permissions(self.request.user,
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self._registry[step_class])]
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def _order_steps(self):
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steps = list(copy.copy(self.default_steps))
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additional = self._registry.keys()
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for step in additional:
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try:
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min_pos = steps.index(step.after)
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except ValueError:
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min_pos = 0
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try:
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max_pos = steps.index(step.before)
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except ValueError:
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max_pos = len(steps)
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if min_pos > max_pos:
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raise exceptions.WorkflowError("The step %(new)s can't be "
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"placed between the steps "
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"%(after)s and %(before)s; the "
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"step %(before)s comes before "
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"%(after)s."
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% {"new": additional,
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"after": step.after,
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"before": step.before})
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steps.insert(max_pos, step)
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return steps
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def get_entry_point(self):
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"""
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Returns the slug of the step which the workflow should begin on.
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This method takes into account both already-available data and errors
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within the steps.
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"""
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# If we have a valid specified entry point, use it.
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if self.entry_point:
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if self.get_step(self.entry_point):
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return self.entry_point
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# Otherwise fall back to calculating the appropriate entry point.
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for step in self.steps:
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if step.has_errors:
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return step.slug
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try:
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step._verify_contributions(self.context)
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except exceptions.WorkflowError:
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return step.slug
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# If nothing else, just return the first step.
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return self.steps[0].slug
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def _trigger_handlers(self, key):
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responses = []
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handlers = [(step.slug, f) for step in self.steps
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for f in step._handlers.get(key, [])]
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for slug, handler in handlers:
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responses.append((slug, handler(self.request, self.context)))
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return responses
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@classmethod
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def register(cls, step_class):
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""" Registers a :class:`~horizon.workflows.Step` with the workflow. """
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if not inspect.isclass(step_class):
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raise ValueError('Only classes may be registered.')
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elif not issubclass(step_class, cls._registerable_class):
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raise ValueError('Only %s classes or subclasses may be registered.'
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% cls._registerable_class.__name__)
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if step_class in cls._cls_registry:
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return False
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else:
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cls._cls_registry.add(step_class)
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return True
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@classmethod
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def unregister(cls, step_class):
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"""
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Unregisters a :class:`~horizon.workflows.Step` from the workflow.
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"""
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try:
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cls._cls_registry.remove(step_class)
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except KeyError:
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raise base.NotRegistered('%s is not registered' % cls)
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return cls._unregister(step_class)
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def validate(self, context):
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"""
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Hook for custom context data validation. Should return a boolean
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value or raise :class:`~horizon.exceptions.WorkflowValidationError`.
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"""
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return True
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def is_valid(self):
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"""
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Verified that all required data is present in the context and
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calls the ``validate`` method to allow for finer-grained checks
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on the context data.
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"""
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missing = self.depends_on - set(self.context.keys())
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if missing:
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raise exceptions.WorkflowValidationError(
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"Unable to complete the workflow. The values %s are "
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"required but not present." % ", ".join(missing))
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# Validate each step. Cycle through all of them to catch all errors
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# in one pass before returning.
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steps_valid = True
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for step in self.steps:
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if not step.action.is_valid():
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steps_valid = False
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step.has_errors = True
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if not steps_valid:
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return steps_valid
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return self.validate(self.context)
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def finalize(self):
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"""
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Finalizes a workflow by running through all the actions in order
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and calling their ``handle`` methods. Returns ``True`` on full success,
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or ``False`` for a partial success, e.g. there were non-critical
|
|
errors. (If it failed completely the function wouldn't return.)
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"""
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partial = False
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for step in self.steps:
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try:
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data = step.action.handle(self.request, self.context)
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if data is True or data is None:
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continue
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elif data is False:
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partial = True
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else:
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self.context = step.contribute(data or {}, self.context)
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except:
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|
partial = True
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exceptions.handle(self.request)
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if not self.handle(self.request, self.context):
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partial = True
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return not partial
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def handle(self, request, context):
|
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"""
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Handles any final processing for this workflow. Should return a boolean
|
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value indicating success.
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"""
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return True
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|
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def get_success_url(self):
|
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"""
|
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Returns a URL to redirect the user to upon completion. By default it
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will attempt to parse a ``success_url`` attribute on the workflow,
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|
which can take the form of a reversible URL pattern name, or a
|
|
standard HTTP URL.
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"""
|
|
try:
|
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return urlresolvers.reverse(self.success_url)
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|
except urlresolvers.NoReverseMatch:
|
|
return self.success_url
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|
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def format_status_message(self, message):
|
|
"""
|
|
Hook to allow customization of the message returned to the user
|
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upon successful or unsuccessful completion of the workflow.
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By default it simply inserts the workflow's name into the message
|
|
string.
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"""
|
|
if "%s" in message:
|
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return message % self.name
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else:
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|
return message
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|
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def render(self):
|
|
""" Renders the workflow. """
|
|
workflow_template = template.loader.get_template(self.template_name)
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|
extra_context = {"workflow": self}
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|
if self.request.is_ajax():
|
|
extra_context['modal'] = True
|
|
context = template.RequestContext(self.request, extra_context)
|
|
return workflow_template.render(context)
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|
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def get_absolute_url(self):
|
|
""" Returns the canonical URL for this workflow.
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|
|
|
This is used for the POST action attribute on the form element
|
|
wrapping the workflow.
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|
|
For convenience it defaults to the value of
|
|
``request.get_full_path()`` with any query string stripped off,
|
|
e.g. the path at which the workflow was requested.
|
|
"""
|
|
return self.request.get_full_path().partition('?')[0]
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|
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def add_error_to_step(self, message, slug):
|
|
"""
|
|
Adds an error to the workflow's Step with the
|
|
specifed slug based on API issues. This is useful
|
|
when you wish for API errors to appear as errors on
|
|
the form rather than using the messages framework.
|
|
"""
|
|
step = self.get_step(slug)
|
|
if step:
|
|
step.add_error(message)
|