migrations: add migration script for Node model changes

Sync DB to model changes after these commits:

    api.models: basic definitions of Node submodels
    api.main: use node endpoints for all type of Node subtypes
    api.db: remove regression collection

Signed-off-by: Ricardo Cañuelo <[email protected]>

migrations/20231215122000_node_models.py

@@ -0,0 +1,137 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+#
+# Copyright (C) 2023 Collabora Limited
+# Author: Ricardo Cañuelo <[email protected]>
+
+"""Migration for Node objects to comply with the models after commits:
+
+    api.models: basic definitions of Node submodels
+    api.main: use node endpoints for all type of Node subtypes
+    api.db: remove regression collection
+
+"""
+
+from bson.objectid import ObjectId
+
+name = '20231215122000_node_models'
+dependencies = ['20231102101356_user']
+
+
+def node_upgrade_needed(node):
+    """Checks if a DB Node passed as a parameter needs to be migrated
+    with this script.
+
+    Parameters:
+      user: a mongodb document (dict) defining a KernelCI Node
+
+    Returns:
+      True if the node needs to be migrated, False otherwise
+
+    """
+    # The existence of a 'revision' key seems to be enough to detect a
+    # pre-migration Node
+    if 'revision' in node:
+        return True
+    else:
+        return False
+
+
+def upgrade(db: "pymongo.database.Database"):
+    # Update nodes
+    nodes = db.node.find()
+    for node in nodes:
+        # Skip any node that's not in the old format
+        if not node_upgrade_needed(node):
+            continue
+        if not node.get('data'):
+            # Initialize 'data' field if it's empty: a generic Node
+            # with no specific type may have an emtpy 'data' field
+            db.node.update_one(
+                {'_id': node['_id']},
+                {'$set': {'data': {}}}
+            )
+        # move 'revision' to 'data.kernel_revision'
+        db.node.update_one(
+            {'_id': node['_id']},
+            {
+                '$set': {
+                    'data.kernel_revision': node['revision']
+                },
+                '$unset': {'revision': ''}
+            }
+        )
+
+    # Re-format regressions: move them from "regression" to "node"
+    regressions = db.regression.find()
+    for regression in regressions:
+        db.node.insert_one(
+            {
+                'name': regression.get('name'),
+                'group': regression.get('group'),
+                'path': regression.get('path'),
+                'kind': 'regression',
+                'data': {
+                    'pass_node': ObjectId(regression['regression_data'][0]),
+                    'fail_node': ObjectId(regression['regression_data'][1])
+                },
+                'artifacts': regression.get('artifacts'),
+                'created': regression.get('created'),
+                'updated': regression.get('updated'),
+                'timeout': regression.get('timeout'),
+                'owner': regression.get('owner'),
+            }
+        )
+        db.regression.delete_one({'_id': regression['_id']})
+
+
+def downgrade(db: 'pymongo.database.Database'):
+    # Move regressions back to "regression"
+    regressions = db.node.find({'kind': 'regression'})
+    for regression in regressions:
+        fail_node = db.node.find_one(
+            {'_id': ObjectId(regression['data']['fail_node'])}
+        )
+        db.regression.insert_one(
+            {
+                'name': regression.get('name'),
+                'group': regression.get('group'),
+                'path': regression.get('path'),
+                'kind': 'regression',
+                'parent': regression['data']['fail_node'],
+                'regression_data': [
+                    regression['data']['pass_node'],
+                    regression['data']['fail_node']
+                ],
+                'revision': fail_node['data']['kernel_revision'],
+                'artifacts': regression.get('artifacts'),
+                'created': regression.get('created'),
+                'updated': regression.get('updated'),
+                'timeout': regression.get('timeout'),
+                'owner': regression.get('owner'),
+            }
+        )
+        db.node.delete_one({'_id': regression['_id']})
+
+    # Downgrade node format
+    nodes = db.node.find()
+    for node in nodes:
+        # Skip any node that's already in the old format
+        if node_upgrade_needed(node):
+            continue
+        # move 'data.kernel_revision' to 'revision'
+        db.node.update_one(
+            {'_id': node['_id']},
+            {
+                '$set': {
+                    'revision': node['data']['kernel_revision']
+                },
+                '$unset': {'data.kernel_revision': ''}
+            }
+        )
+        # unset 'data' if it's empty
+        node['data'].pop('kernel_revision', None)
+        if len(node['data']) == 0:
+            db.node.update_one(
+                {'_id': node['_id']},
+                {'$unset': {'data': ''}}
+            )