feat(alerts): Migration to backfill existing orgs with `alerts_member_write: False` (#22852)

This migration is required to run before #22924 can be merged.

The migration simply backfills existing orgs with the OrganizationOption alerts_member_write: False. This will make sure that when we add the option from #22924, members of existing orgs won't be able to edit alerts unless the org opts into that specifically.

migrations_lockfile.txt

@@ -10,7 +10,7 @@ auth: 0008_alter_user_username_max_length
 contenttypes: 0002_remove_content_type_name
 jira_ac: 0001_initial
 nodestore: 0001_initial
-sentry: 0145_rename_alert_rule_feature
+sentry: 0146_backfill_members_alert_write
 sessions: 0001_initial
 sites: 0002_alter_domain_unique
 social_auth: 0001_initial

src/sentry/migrations/0146_backfill_members_alert_write.py

@@ -0,0 +1,51 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.28 on 2020-07-28 16:24
+from __future__ import unicode_literals
+
+from django.db import migrations, transaction
+
+from sentry.utils.query import RangeQuerySetWrapperWithProgressBar
+
+import logging
+
+
+def backfill_existing_orgs(apps, schema_editor):
+    """
+    Backfill the OrganizationOption alerts_member_write to be False for existing orgs
+    """
+    Organization = apps.get_model("sentry", "Organization")
+    OrganizationOption = apps.get_model("sentry", "OrganizationOption")
+
+    for org in RangeQuerySetWrapperWithProgressBar(Organization.objects.all()):
+        if org.status != 0:
+            continue
+        try:
+            OrganizationOption.objects.create(organization=org, key='sentry:alerts_member_write', value=False)
+        except Exception:
+            logging.exception("Error backfilling organization {}".format(org.id))
+
+
+
+class Migration(migrations.Migration):
+    # This flag is used to mark that a migration shouldn't be automatically run in
+    # production. We set this to True for operations that we think are risky and want
+    # someone from ops to run manually and monitor.
+    # General advice is that if in doubt, mark your migration as `is_dangerous`.
+    # Some things you should always mark as dangerous:
+    # - Large data migrations. Typically we want these to be run manually by ops so that
+    #   they can be monitored. Since data migrations will now hold a transaction open
+    #   this is even more important.
+    # - Adding columns to highly active tables, even ones that are NULL.
+    is_dangerous = True
+
+    # This flag is used to decide whether to run this migration in a transaction or not.
+    # By default we prefer to run in a transaction, but for migrations where you want
+    # to `CREATE INDEX CONCURRENTLY` this needs to be set to False. Typically you'll
+    # want to create an index concurrently when adding one to an existing table.
+    atomic = False
+
+    dependencies = [
+        ('sentry', '0145_rename_alert_rule_feature'),
+    ]
+
+    operations = [migrations.RunPython(code=backfill_existing_orgs)]