Define author_search_vector_trigger via Author.Meta.triggers

Previously, triggers lived only in a particular migration file. With
this change, code for the triggers resides in the model, and their
lifecycle is managed through normal Django migrations.

bookwyrm/migrations/0191_migrate_search_vec_triggers_to_pgtriggers.py

@@ -0,0 +1,50 @@
+# Generated by Django 3.2.20 on 2023-11-25 00:47
+
+from importlib import import_module
+import re
+
+from django.db import migrations
+import pgtrigger.compiler
+import pgtrigger.migrations
+
+trigger_migration = import_module("bookwyrm.migrations.0077_auto_20210623_2155")
+
+# it's _very_ convenient for development that this migration be reversible
+search_vector_trigger = trigger_migration.Migration.operations[4]
+author_search_vector_trigger = trigger_migration.Migration.operations[5]
+
+
+assert re.search(r"\bCREATE TRIGGER search_vector_trigger\b", search_vector_trigger.sql)
+assert re.search(
+    r"\bCREATE TRIGGER author_search_vector_trigger\b",
+    author_search_vector_trigger.sql,
+)
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("bookwyrm", "0190_book_search_updates"),
+    ]
+
+    operations = [
+        pgtrigger.migrations.AddTrigger(
+            model_name="author",
+            trigger=pgtrigger.compiler.Trigger(
+                name="reset_search_vector_on_author_edit",
+                sql=pgtrigger.compiler.UpsertTriggerSql(
+                    func="WITH book AS (SELECT bookwyrm_book.id AS row_id FROM bookwyrm_author LEFT OUTER JOIN bookwyrm_book_authors ON bookwyrm_book_authors.id = new.id LEFT OUTER JOIN bookwyrm_book ON bookwyrm_book.id = bookwyrm_book_authors.book_id) UPDATE bookwyrm_book SET search_vector = '' FROM book WHERE id = book.row_id;RETURN NEW;",
+                    hash="9c0a472e2bf60e63d593cce49f47972c7b227a00",
+                    operation='UPDATE OF "name"',
+                    pgid="pgtrigger_reset_search_vector_on_author_edit_a447c",
+                    table="bookwyrm_author",
+                    when="AFTER",
+                ),
+            ),
+        ),
+        migrations.RunSQL(
+            sql="""DROP TRIGGER IF EXISTS author_search_vector_trigger ON bookwyrm_author;
+                   DROP FUNCTION IF EXISTS author_trigger;
+            """,
+            reverse_sql=author_search_vector_trigger.sql,
+        ),
+    ]

bookwyrm/models/author.py

@@ -3,9 +3,11 @@
 from typing import Tuple, Any
 
 from django.db import models
+import pgtrigger
 
 from bookwyrm import activitypub
 from bookwyrm.settings import DOMAIN
+from bookwyrm.utils.db import format_trigger
 
 from .book import BookDataModel
 from . import fields
@@ -66,4 +68,31 @@ def get_remote_id(self):
         """editions and works both use "book" instead of model_name"""
         return f"https://{DOMAIN}/author/{self.id}"
 
+    class Meta:
+        "sets up indexes and triggers"
+
+        triggers = [
+            pgtrigger.Trigger(
+                name="reset_search_vector_on_author_edit",
+                when=pgtrigger.After,
+                operation=pgtrigger.UpdateOf("name"),
+                func=format_trigger(
+                    """WITH book AS (
+                          SELECT bookwyrm_book.id AS row_id
+                          FROM bookwyrm_author
+                          LEFT OUTER JOIN bookwyrm_book_authors
+                            ON bookwyrm_book_authors.id = new.id
+                          LEFT OUTER JOIN bookwyrm_book
+                            ON bookwyrm_book.id = bookwyrm_book_authors.book_id
+                    )
+                    UPDATE bookwyrm_book
+                    SET search_vector = ''
+                    FROM book
+                    WHERE id = book.row_id;
+                    RETURN new;
+                """
+                ),
+            )
+        ]
+
     activity_serializer = activitypub.Author

bookwyrm/settings.py

@@ -104,6 +104,7 @@
     "celery",
     "django_celery_beat",
     "imagekit",
+    "pgtrigger",
     "storages",
 ]
 

bookwyrm/utils/db.py

@@ -0,0 +1,18 @@
+""" Database utilities """
+
+import sqlparse
+
+
+def format_trigger(sql: str) -> str:
+    """format SQL trigger before storing
+
+    we remove whitespace and use consistent casing so as to avoid migrations
+    due to formatting changes.
+    """
+    return sqlparse.format(
+        sql,
+        strip_comments=True,
+        strip_whitespace=True,
+        keyword_case="upper",
+        identifier_case="lower",
+    )

requirements.txt

@@ -7,6 +7,7 @@ django-celery-beat==2.4.0
 django-compressor==4.3.1
 django-imagekit==4.1.0
 django-model-utils==4.3.1
+django-pgtrigger==4.10.0
 django-sass-processor==1.2.2
 django-csp==3.7
 environs==9.5.0