fix(awareness-service): dedupe deliveries by content hash so envelope updates re-deliver (#989)

* fix(awareness-service): dedupe deliveries by content hash so envelope updates re-deliver (#984)

* fix(awareness-service): use generated migration timestamp and safe nullable-backfill-notnull column add

Author: coodos

services/awareness-service/api/src/database/migrations/1780404367748-AddDeliveryContentHash.ts

@@ -0,0 +1,47 @@
+import { MigrationInterface, QueryRunner } from "typeorm";
+
+/**
+ * Dedupe deliveries by payload content, not packet id alone. Adds a
+ * `contentHash` column to `deliveries` and swaps the unique key from
+ * (subscriptionId, packetId) to (subscriptionId, packetId, contentHash) so that
+ * re-ingesting an updated MetaEnvelope queues a fresh delivery instead of being
+ * silently dropped by the old constraint.
+ */
+export class AddDeliveryContentHash1780404367748 implements MigrationInterface {
+    name = "AddDeliveryContentHash1780404367748";
+
+    public async up(queryRunner: QueryRunner): Promise<void> {
+        // Add nullable first, then backfill: a straight `ADD ... NOT NULL`
+        // fails on any table that already has delivery rows.
+        await queryRunner.query(
+            `ALTER TABLE "deliveries" ADD "contentHash" character varying`,
+        );
+        // Backfill legacy rows with a single constant. This preserves the old
+        // one-delivery-per-(subscription, packet) semantics for rows that
+        // predate content-based dedup.
+        await queryRunner.query(
+            `UPDATE "deliveries" SET "contentHash" = '' WHERE "contentHash" IS NULL`,
+        );
+        await queryRunner.query(
+            `ALTER TABLE "deliveries" ALTER COLUMN "contentHash" SET NOT NULL`,
+        );
+        await queryRunner.query(
+            `ALTER TABLE "deliveries" DROP CONSTRAINT "uq_delivery_subscription_packet"`,
+        );
+        await queryRunner.query(
+            `ALTER TABLE "deliveries" ADD CONSTRAINT "uq_delivery_subscription_packet_content" UNIQUE ("subscriptionId", "packetId", "contentHash")`,
+        );
+    }
+
+    public async down(queryRunner: QueryRunner): Promise<void> {
+        await queryRunner.query(
+            `ALTER TABLE "deliveries" DROP CONSTRAINT "uq_delivery_subscription_packet_content"`,
+        );
+        await queryRunner.query(
+            `ALTER TABLE "deliveries" DROP COLUMN "contentHash"`,
+        );
+        await queryRunner.query(
+            `ALTER TABLE "deliveries" ADD CONSTRAINT "uq_delivery_subscription_packet" UNIQUE ("subscriptionId", "packetId")`,
+        );
+    }
+}