def create(self, validated_data, **kwargs):
"""Create the new workflow."""
wflow_name = self.context.get('name')
if not wflow_name:
wflow_name = self.validated_data.get('name')
if not wflow_name:
raise Exception(_('Unexpected empty workflow name.'))
if Workflow.objects.filter(name=wflow_name,
user=self.context['user']).exists():
raise Exception(
_('There is a workflow with this name. ' +
'Please provide a workflow name in the import page.'))
# Initial values
workflow_obj = None
try:
workflow_obj = Workflow(
user=self.context['user'],
name=wflow_name,
description_text=validated_data['description_text'],
nrows=0,
ncols=0,
attributes=validated_data['attributes'],
query_builder_ops=validated_data.get('query_builder_ops', {}),
)
workflow_obj.save()
# Create the columns
column_data = ColumnSerializer(data=validated_data.get(
'columns', []),
many=True,
context={'workflow': workflow_obj})
# And save its content
if column_data.is_valid():
columns = column_data.save()
else:
raise Exception(_('Unable to save column information'))
# If there is any column with position = 0, recompute (this is to
# guarantee backward compatibility.
if any(col.position == 0 for col in columns):
for idx, col in enumerate(columns):
col.position = idx + 1
col.save()
# Load the data frame
data_frame = validated_data.get('data_frame')
if data_frame is not None:
# Store the table in the DB
store_table(
data_frame,
workflow_obj.get_data_frame_table_name(),
dtype={
col.name: col.data_type
for col in workflow_obj.columns.all()
},
)
# Reconcile now the information in workflow and columns with
# the one loaded
workflow_obj.ncols = validated_data['ncols']
workflow_obj.nrows = validated_data['nrows']
workflow_obj.save()
# Create the actions pointing to the workflow
action_data = ActionSerializer(data=validated_data.get(
'actions', []),
many=True,
context={
'workflow': workflow_obj,
'columns': columns
})
if action_data.is_valid():
action_data.save()
else:
raise Exception(_('Unable to save column information'))
# Create the views pointing to the workflow
view_data = ViewSerializer(data=validated_data.get('views', []),
many=True,
context={
'workflow': workflow_obj,
'columns': columns
})
if view_data.is_valid():
view_data.save()
else:
raise Exception(_('Unable to save column information'))
except Exception:
# Get rid of the objects created
if workflow_obj:
if workflow_obj.id:
workflow_obj.delete()
raise
return workflow_obj
def workflow_delete_column(
workflow: Workflow,
column: Column,
cond_to_delete: Optional[List[Condition]] = None,
):
"""Remove column from workflow.
Given a workflow and a column, removes it from the workflow (and the
corresponding data frame
:param workflow: Workflow object
:param column: Column object to delete
:param cond_to_delete: List of conditions to delete after removing the
column
:return: Nothing. Effect reflected in the database
"""
# Drop the column from the DB table storing the data frame
df_drop_column(workflow.get_data_frame_table_name(), column.name)
# Reposition the columns above the one being deleted
workflow.reposition_columns(column.position, workflow.ncols + 1)
# Delete the column
column.delete()
# Update the information in the workflow
workflow.ncols = workflow.ncols - 1
workflow.save()
if not cond_to_delete:
# The conditions to delete are not given, so calculate them
# Get the conditions/actions attached to this workflow
cond_to_delete = [
cond
for cond in Condition.objects.filter(action__workflow=workflow, )
if column in cond.columns.all()
]
# If a column disappears, the conditions that contain that variable
# are removed
actions_without_filters = []
for condition in cond_to_delete:
if condition.is_filter:
actions_without_filters.append(condition.action)
# Formula has the name of the deleted column. Delete it
condition.delete()
# Traverse the actions for which the filter has been deleted and reassess
# all their conditions
# TODO: Explore how to do this asynchronously (or lazy)
map(lambda act: act.update_n_rows_selected(), actions_without_filters)
# If a column disappears, the views that contain only that column need to
# disappear as well as they are no longer relevant.
for view in workflow.views.all():
if view.columns.count() == 0:
view.delete()
