fix IntegrityErrors occuring when creating ResolutionNoteSlackMessage…

… objects (#2933)

# What this PR does

## Which issue(s) this PR fixes

Closes grafana/oncall-private#1822

## Checklist

- [x] Unit, integration, and e2e (if applicable) tests updated
- [x] Documentation added (or `pr:no public docs` PR label added if not
required)
- [x] `CHANGELOG.md` updated (or `pr:no changelog` PR label added if not
required)

CHANGELOG.md

@@ -23,10 +23,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - Fix issue with helm chart when specifying `broker.type=rabbitmq` where Redis environment variables
-  were not longer being injected @joeyorlando ([#2927](https://github.com/grafana/oncall/pull/2927))
+  were not longer being injected by @joeyorlando ([#2927](https://github.com/grafana/oncall/pull/2927))
 - Fix silence for alert groups with empty escalation chain @Ferril ([#2929](https://github.com/grafana/oncall/pull/2929))
 - Fixed NPE when migrating legacy Grafana Alerting integrations
   ([#2908](https://github.com/grafana/oncall/issues/2908))
+- Fix `IntegrityError` exceptions that occasionally would occur when trying to create `ResolutionNoteSlackMessage`
+  objects by @joeyorlando ([#2933](https://github.com/grafana/oncall/pull/2933))
 
 ## v1.3.29 (2023-08-29)
 

engine/apps/alerts/migrations/0031_auto_20230831_1445.py

@@ -0,0 +1,21 @@
+# Generated by Django 3.2.20 on 2023-08-31 14:45
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('alerts', '0030_auto_20230731_0341'),
+    ]
+
+    operations = [
+        migrations.AddIndex(
+            model_name='resolutionnoteslackmessage',
+            index=models.Index(fields=['ts', 'thread_ts', 'alert_group_id'], name='alerts_reso_ts_08f72c_idx'),
+        ),
+        migrations.AddIndex(
+            model_name='resolutionnoteslackmessage',
+            index=models.Index(fields=['ts', 'thread_ts', 'slack_channel_id'], name='alerts_reso_ts_a9bdf7_idx'),
+        ),
+    ]

engine/apps/alerts/models/resolution_note.py

@@ -83,6 +83,11 @@ class ResolutionNoteSlackMessage(models.Model):
     class Meta:
         unique_together = ("thread_ts", "ts")
 
+        indexes = [
+            models.Index(fields=["ts", "thread_ts", "alert_group_id"]),
+            models.Index(fields=["ts", "thread_ts", "slack_channel_id"]),
+        ]
+
     def get_resolution_note(self) -> typing.Optional["ResolutionNote"]:
         try:
             return self.resolution_note

engine/apps/slack/scenarios/slack_channel_integration.py

@@ -82,46 +82,31 @@ def save_thread_message_for_resolution_note(
         if result["permalink"] is not None:
             permalink = result["permalink"]
 
-        try:
-            slack_thread_message = ResolutionNoteSlackMessage.objects.get(
-                ts=message_ts,
-                thread_ts=thread_ts,
-                alert_group=alert_group,
+        if len(text) > 2900:
+            self._slack_client.api_call(
+                "chat.postEphemeral",
+                channel=channel,
+                user=slack_user_identity.slack_id,
+                text=":warning: Unable to show the <{}|message> in Resolution Note: the message is too long ({}). "
+                "Max length - 2900 symbols.".format(permalink, len(text)),
             )
-            if len(text) > 2900:
-                if slack_thread_message.added_to_resolution_note:
-                    self._slack_client.api_call(
-                        "chat.postEphemeral",
-                        channel=channel,
-                        user=slack_user_identity.slack_id,
-                        text=":warning: Unable to update the <{}|message> in Resolution Note: the message is too long ({}). "
-                        "Max length - 2900 symbols.".format(permalink, len(text)),
-                    )
-                return
-            slack_thread_message.text = text
-            slack_thread_message.save()
+            return
 
-        except ResolutionNoteSlackMessage.DoesNotExist:
-            if len(text) > 2900:
-                self._slack_client.api_call(
-                    "chat.postEphemeral",
-                    channel=channel,
-                    user=slack_user_identity.slack_id,
-                    text=":warning: The <{}|message> will not be displayed in Resolution Note: "
-                    "the message is too long ({}). Max length - 2900 symbols.".format(permalink, len(text)),
-                )
-                return
-
-            slack_thread_message = ResolutionNoteSlackMessage(
-                alert_group=alert_group,
-                user=self.user,
-                added_by_user=self.user,
-                text=text,
-                slack_channel_id=channel,
-                thread_ts=thread_ts,
-                ts=message_ts,
-                permalink=permalink,
-            )
+        slack_thread_message, created = ResolutionNoteSlackMessage.objects.get_or_create(
+            ts=message_ts,
+            thread_ts=thread_ts,
+            alert_group=alert_group,
+            defaults={
+                "user": self.user,
+                "added_by_user": self.user,
+                "text": text,
+                "slack_channel_id": channel,
+                "permalink": permalink,
+            },
+        )
+
+        if not created:
+            slack_thread_message.text = text
             slack_thread_message.save()
 
     def delete_thread_message_from_resolution_note(