Throw an error if trying to create a process lock that already exists. Names should be unique

src/khoj/database/adapters/__init__.py

@@ -16,6 +16,7 @@ from django.contrib.sessions.backends.db import SessionStore
 from django.db import models
 from django.db.models import Q
 from django.db.models.manager import BaseManager
+from django.db.utils import IntegrityError
 from django_apscheduler.models import DjangoJob, DjangoJobExecution
 from fastapi import HTTPException
 from pgvector.django import CosineDistance
@@ -457,6 +458,9 @@ class ProcessLockAdapters:
             with timer(f"🔒 Run {func} with {operation} process lock", logger):
                 func(**kwargs)
             success = True
+        except IntegrityError as e:
+            logger.error(f"⚠️ Unable to create the process lock for {func} with {operation}: {e}", exc_info=True)
+            success = False
         except Exception as e:
             logger.error(f"🚨 Error executing {func} with {operation} process lock: {e}", exc_info=True)
             success = False

src/khoj/database/migrations/0041_alter_processlock_name.py

@@ -0,0 +1,26 @@
+# Generated by Django 4.2.10 on 2024-05-04 13:12
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    def delete_all_existing_process_locks(apps, schema_editor):
+        ProcessLock = apps.get_model("database", "ProcessLock")
+        ProcessLock.objects.all().delete()
+
+    dependencies = [
+        ("database", "0040_merge_20240504_1010"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="processlock",
+            name="name",
+            field=models.CharField(
+                choices=[("index_content", "Index Content"), ("scheduled_job", "Scheduled Job")],
+                max_length=200,
+                unique=True,
+            ),
+        ),
+        migrations.RunPython(delete_all_existing_process_locks),
+    ]

src/khoj/database/models/__init__.py

@@ -114,7 +114,7 @@ class ProcessLock(BaseModel):
 
     # We need to make sure that some operations are thread-safe. To do so, add locks for potentially shared operations.
     # For example, we need to make sure that only one process is updating the embeddings at a time.
-    name = models.CharField(max_length=200, choices=Operation.choices)
+    name = models.CharField(max_length=200, choices=Operation.choices, unique=True)
     started_at = models.DateTimeField(auto_now_add=True)
     max_duration_in_seconds = models.IntegerField(default=60 * 60 * 12)  # 12 hours