feat: add basic support for batch execution

no execution options yet, and no progress indicator

also basic delete support, invoking handler

src/wuttaweb/views/batch.py

@@ -28,6 +28,7 @@ import logging
 import threading
 import time
 
+import markdown
 from sqlalchemy import orm
 
 from wuttaweb.views import MasterView
@@ -41,6 +42,13 @@ log = logging.getLogger(__name__)
 class BatchMasterView(MasterView):
     """
     Base class for all "batch master" views.
+
+    .. attribute:: batch_handler
+
+       Reference to the :term:`batch handler` for use with the view.
+
+       This is set when the view is first created, using return value
+       from :meth:`get_batch_handler()`.
     """
 
     labels = {
@@ -66,6 +74,46 @@ class BatchMasterView(MasterView):
         """
         raise NotImplementedError
 
+    def get_fallback_templates(self, template):
+        """
+        We override the default logic here, to prefer "batch"
+        templates over the "master" templates.
+
+        So for instance the "view batch" page will by default use the
+        ``/batch/view.mako`` template - which does inherit from
+        ``/master/view.mako`` but adds extra features specific to
+        batches.
+        """
+        templates = super().get_fallback_templates(template)
+        templates.insert(0, f'/batch/{template}.mako')
+        return templates
+
+    def render_to_response(self, template, context):
+        """
+        We override the default logic here, to inject batch-related
+        context for the
+        :meth:`~wuttaweb.views.master.MasterView.view()` template
+        specifically.  These values are used in the template file,
+        ``/batch/view.mako``.
+
+        * ``batch`` - reference to the current :term:`batch`
+        * ``batch_handler`` reference to :attr:`batch_handler`
+        * ``why_not_execute`` - text of reason (if any) not to execute batch
+        * ``execution_described`` - HTML (rendered from markdown) describing batch execution
+        """
+        if template == 'view':
+            batch = context['instance']
+            context['batch'] = batch
+            context['batch_handler'] = self.batch_handler
+            context['why_not_execute'] = self.batch_handler.why_not_execute(batch)
+
+            description = (self.batch_handler.describe_execution(batch)
+                           or "Handler does not say!  Your guess is as good as mine.")
+            context['execution_described'] = markdown.markdown(
+                description, extensions=['fenced_code', 'codehilite'])
+
+        return super().render_to_response(template, context)
+
     def configure_grid(self, g):
         """ """
         super().configure_grid(g)
@@ -208,6 +256,20 @@ class BatchMasterView(MasterView):
         thread.start()
         return self.render_progress(progress)
 
+    def delete_instance(self, batch):
+        """
+        Delete the given batch instance.
+
+        This calls
+        :meth:`~wuttjamaican:wuttjamaican.batch.BatchHandler.do_delete()`
+        on the :attr:`batch_handler`.
+        """
+        self.batch_handler.do_delete(batch, self.request.user)
+
+    ##############################
+    # populate methods
+    ##############################
+
     def populate_thread(self, batch_uuid, progress=None):
         """
         Thread target for populating new object with progress indicator.
@@ -258,6 +320,31 @@ class BatchMasterView(MasterView):
         finally:
             session.close()
 
+    ##############################
+    # execute methods
+    ##############################
+
+    def execute(self):
+        """
+        View to execute the current :term:`batch`.
+
+        Eventually this should show a progress indicator etc., but for
+        now it simply calls
+        :meth:`~wuttjamaican:wuttjamaican.batch.BatchHandler.do_execute()`
+        on the :attr:`batch_handler` and waits for it to complete,
+        then redirects user back to the "view batch" page.
+        """
+        self.executing = True
+        batch = self.get_instance()
+
+        try:
+            self.batch_handler.do_execute(batch, self.request.user)
+        except Exception as error:
+            log.warning("failed to execute batch: %s", batch, exc_info=True)
+            self.request.session.flash(f"Execution failed!: {error}", 'error')
+
+        return self.redirect(self.get_action_url('view', batch))
+
     ##############################
     # row methods
     ##############################
@@ -287,3 +374,31 @@ class BatchMasterView(MasterView):
         super().configure_row_grid(g)
 
         g.set_label('sequence', "Seq.", column_only=True)
+
+    ##############################
+    # configuration
+    ##############################
+
+    @classmethod
+    def defaults(cls, config):
+        """ """
+        cls._defaults(config)
+        cls._batch_defaults(config)
+
+    @classmethod
+    def _batch_defaults(cls, config):
+        route_prefix = cls.get_route_prefix()
+        permission_prefix = cls.get_permission_prefix()
+        model_title = cls.get_model_title()
+        instance_url_prefix = cls.get_instance_url_prefix()
+
+        # execute
+        config.add_route(f'{route_prefix}.execute',
+                         f'{instance_url_prefix}/execute',
+                         request_method='POST')
+        config.add_view(cls, attr='execute',
+                        route_name=f'{route_prefix}.execute',
+                        permission=f'{permission_prefix}.execute')
+        config.add_wutta_permission(permission_prefix,
+                                    f'{permission_prefix}.execute',
+                                    f"Execute {model_title}")