Add progress support for bulk deletion

plus bulk-delete all tempmon readings when deleting client or probe

tailbone/views/master.py

@@ -32,9 +32,11 @@ from sqlalchemy import orm
 
 import sqlalchemy_continuum as continuum
 
+from rattail.db import Session as RattailSession
 from rattail.db.continuum import model_transaction_query
 from rattail.util import prettify
 from rattail.time import localtime
+from rattail.threads import Thread
 
 import formalchemy as fa
 from pyramid import httpexceptions
@@ -43,6 +45,7 @@ from webhelpers2.html import HTML, tags
 
 from tailbone import forms, grids
 from tailbone.views import View
+from tailbone.progress import SessionProgress
 
 
 class MasterView(View):
@@ -702,20 +705,60 @@ class MasterView(View):
         Delete all records matching the current grid query
         """
         if self.request.method == 'POST':
-            query = self.get_effective_query(sortable=False)
-            count = query.count()
-            self.bulk_delete_objects(query)
-            self.request.session.flash("Deleted {:,d} {}".format(count, self.get_model_title_plural()))
+            key = '{}.bulk_delete'.format(self.model_class.__tablename__)
+            objects = self.get_effective_data()
+            progress = SessionProgress(self.request, key)
+            thread = Thread(target=self.bulk_delete_thread, args=(objects, progress))
+            thread.start()
+            return self.render_progress({
+                'key': key,
+                'cancel_url': self.get_index_url(),
+                'cancel_msg': "Bulk deletion was canceled",
+            })
         else:
             self.request.session.flash("Sorry, you must POST to do a bulk delete operation")
         return self.redirect(self.get_index_url())
 
-    def bulk_delete_objects(self, query):
-        # TODO: sometimes the first makes sense, and would be preferred for
-        # efficiency's sake.  might even need to add progress to latter?
-        # query.delete(synchronize_session=False)
-        for obj in query:
-            self.Session.delete(obj)
+    def bulk_delete_objects(self, session, objects, progress=None):
+
+        def delete(obj, i):
+            session.delete(obj)
+
+        self.progress_loop(delete, objects, progress,
+                           message="Deleting objects")
+
+    def get_bulk_delete_session(self):
+        return RattailSession()
+
+    def bulk_delete_thread(self, objects, progress):
+        """
+        Thread target for bulk-deleting current results, with progress.
+        """
+        session = self.get_bulk_delete_session()
+        objects = objects.with_session(session).all()
+        try:
+            self.bulk_delete_objects(session, objects, progress=progress)
+
+        # If anything goes wrong, rollback and log the error etc.
+        except Exception as error:
+            session.rollback()
+            log.exception("execution failed for batch results")
+            session.close()
+            if progress:
+                progress.session.load()
+                progress.session['error'] = True
+                progress.session['error_msg'] = "Bulk deletion failed: {}: {}".format(type(error).__name__, error)
+                progress.session.save()
+
+        # If no error, check result flag (false means user canceled).
+        else:
+            session.commit()
+            session.close()
+            if progress:
+                progress.session.load()
+                progress.session['complete'] = True
+                progress.session['success_url'] = self.get_index_url()
+                progress.session.save()
 
     def get_merge_fields(self):
         if hasattr(self, 'merge_fields'):