Concurrent Distructive/Intensive ops limits

Provide the ability to limit resource intensive or potentially
wide scale operations which could be a symptom of a highly
distructive and unplanned operation in progress.

The idea behind this change is to help guard the overall deployment
to prevent an overall resource exhaustion situation, or prevent an
attacker with valid credentials from putting an entire deployment
into a potentially disasterous cleaning situation since ironic only
other wise limits concurrency based upon running tasks by conductor.

Story: 2010007
Task: 45140

Change-Id: I642452cd480e7674ff720b65ca32bce59a4a834a

1 files changed, 24 insertions, 0 deletions

diff --git a/ironic/db/sqlalchemy/api.py b/ironic/db/sqlalchemy/api.py
index 05d5cc45e..c14719af8 100644
--- a/ironic/db/sqlalchemy/api.py
+++ b/ironic/db/sqlalchemy/api.py
@@ -30,6 +30,7 @@ from oslo_utils import timeutils
 from oslo_utils import uuidutils
 from osprofiler import sqlalchemy as osp_sqlalchemy
 import sqlalchemy as sa
+from sqlalchemy import or_
 from sqlalchemy.orm.exc import NoResultFound, MultipleResultsFound
 from sqlalchemy.orm import joinedload
 from sqlalchemy.orm import Load
@@ -2400,3 +2401,26 @@ class Connection(api.Connection):
             ).filter(
                 models.NodeHistory.id.in_(entries)
             ).delete(synchronize_session=False)
+
+    def count_nodes_in_provision_state(self, state):
+        if not isinstance(state, list):
+            state = [state]
+        with _session_for_read() as session:
+            # Intentionally does not use the full ORM model
+            # because that is de-duped by pkey, but we already
+            # have unique constraints on UUID/name, so... shouldn't
+            # be a big deal. #JuliaFamousLastWords.
+            # Anyway, intent here is to be as quick as possible and
+            # literally have the DB do *all* of the world, so no
+            # client side ops occur. The column is also indexed,
+            # which means this will be an index based response.
+            # TODO(TheJulia): This might need to be revised for
+            # SQLAlchemy 2.0 as it should be a scaler select and count
+            # instead.
+            return session.query(
+                models.Node.provision_state
+            ).filter(
+                or_(
+                    models.Node.provision_state == v for v in state
+                )
+            ).count()