feat: add structured logging for alert registration and deletion

src/modules/alerts/__tests__/alert.service.test.ts

@@ -5,6 +5,7 @@
 
 import { createAlert, listAlerts, deleteAlert } from '../alert.service';
 import { prisma } from '../../../utils/prisma.utils';
+import { logger } from '../../../utils/logger.utils';
 
 jest.mock('../../../utils/prisma.utils', () => ({
     prisma: {
@@ -17,6 +18,10 @@ jest.mock('../../../utils/prisma.utils', () => ({
     },
 }));
 
+jest.mock('../../../utils/logger.utils', () => ({
+    logger: { info: jest.fn() },
+}));
+
 const mockedPrisma = prisma as jest.Mocked<typeof prisma>;
 
 const VALID_ADDRESS = 'GAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA';
@@ -59,6 +64,19 @@ describe('createAlert', () => {
             },
         });
         expect(result).toEqual(DB_ALERT);
+
+        expect(logger.info).toHaveBeenCalledWith(
+            expect.objectContaining({
+                alert_id: DB_ALERT.id,
+                creator_id: DB_ALERT.creatorId,
+                direction: DB_ALERT.direction,
+                target_price: DB_ALERT.targetPrice,
+                registered_at: DB_ALERT.createdAt,
+                wallet_address: 'GAAA***AAAA',
+            }),
+            'Price alert registered'
+        );
+        expect((logger.info as jest.Mock).mock.calls[0][0]).not.toHaveProperty('callback_url');
     });
 
     it('creates a below-direction alert', async () => {
@@ -114,6 +132,17 @@ describe('deleteAlert', () => {
             where: { id: 'alert-1' },
         });
         expect(result).toEqual({ id: 'alert-1' });
+
+        expect(logger.info).toHaveBeenCalledWith(
+            expect.objectContaining({
+                alert_id: DB_ALERT.id,
+                creator_id: DB_ALERT.creatorId,
+                cancelled_at: expect.any(Date),
+                wallet_address: 'GAAA***AAAA',
+            }),
+            'Price alert cancelled'
+        );
+        expect((logger.info as jest.Mock).mock.calls[0][0]).not.toHaveProperty('callback_url');
     });
 
     it('returns null when the alert is not found', async () => {

src/modules/alerts/alert.service.ts

@@ -13,7 +13,7 @@ export type PriceMovement = {
  * Creates a new price alert for a wallet address watching a creator's key price.
  */
 export async function createAlert(input: CreateAlertInput) {
-    return await prisma.priceAlert.create({
+    const alert = await prisma.priceAlert.create({
         data: {
             creatorId: input.creator_id,
             walletAddress: input.wallet_address,
@@ -22,6 +22,20 @@ export async function createAlert(input: CreateAlertInput) {
             callbackUrl: input.callback_url,
         },
     });
+
+    logger.info(
+        {
+            alert_id: alert.id,
+            creator_id: alert.creatorId,
+            direction: alert.direction,
+            target_price: toNumber(alert.targetPrice),
+            registered_at: alert.createdAt,
+            wallet_address: maskWalletAddress(alert.walletAddress),
+        },
+        'Price alert registered'
+    );
+
+    return alert;
 }
 
 /**
@@ -51,13 +65,29 @@ export async function deleteAlert(
     }
 
     await prisma.priceAlert.delete({ where: { id } });
+
+    logger.info(
+        {
+            alert_id: existing.id,
+            creator_id: existing.creatorId,
+            cancelled_at: new Date(),
+            wallet_address: maskWalletAddress(existing.walletAddress),
+        },
+        'Price alert cancelled'
+    );
+
     return { id };
 }
 
 function toNumber(value: number | string | { toString(): string }): number {
     return typeof value === 'number' ? value : Number(value.toString());
 }
 
+function maskWalletAddress(address: string): string {
+    if (address.length <= 8) return address;
+    return `${address.slice(0, 4)}***${address.slice(-4)}`;
+}
+
 function maskCallbackUrl(callbackUrl: string): string {
     try {
         const url = new URL(callbackUrl);