How to Log Errors in Firebase Cloud Functions

1import { logger } from 'firebase-functions/v2';
2import { onRequest } from 'firebase-functions/v2/https';
3
4// Use logger instead of console.log
5export const myFunction = onRequest(async (req, res) => {
6  logger.info('Function started', { method: req.method, path: req.path });
7
8  try {
9    // Your function logic here
10    logger.info('Operation completed successfully');
11    res.status(200).send('OK');
12  } catch (error) {
13    logger.error('Function failed', { error: String(error) });
14    res.status(500).send('Internal error');
15  }
16});

1import { logger } from 'firebase-functions/v2';
2import { onDocumentCreated } from 'firebase-functions/v2/firestore';
3
4export const onUserCreated = onDocumentCreated(
5  'users/{userId}',
6  async (event) => {
7    const userId = event.params.userId;
8    const userData = event.data?.data();
9
10    logger.info('New user created', {
11      userId,
12      email: userData?.email,
13      provider: userData?.provider,
14      timestamp: new Date().toISOString()
15    });
16
17    try {
18      // Send welcome email, create profile, etc.
19      logger.info('Welcome email sent', { userId });
20    } catch (error: any) {
21      logger.error('Failed to process new user', {
22        userId,
23        errorCode: error.code,
24        errorMessage: error.message,
25        stack: error.stack
26      });
27    }
28  }
29);

1import { logger } from 'firebase-functions/v2';
2import { onCall, HttpsError } from 'firebase-functions/v2/https';
3
4export const processOrder = onCall(async (request) => {
5  const uid = request.auth?.uid;
6  const orderData = request.data;
7
8  logger.info('Processing order', {
9    uid,
10    orderId: orderData.orderId,
11    amount: orderData.amount
12  });
13
14  if (!uid) {
15    logger.warn('Unauthenticated order attempt', {
16      ip: request.rawRequest.ip
17    });
18    throw new HttpsError('unauthenticated', 'Must be signed in');
19  }
20
21  try {
22    // Process the order
23    logger.info('Order processed successfully', {
24      uid,
25      orderId: orderData.orderId
26    });
27    return { success: true };
28  } catch (error: any) {
29    logger.error('Order processing failed', {
30      uid,
31      orderId: orderData.orderId,
32      errorCode: error.code,
33      errorMessage: error.message,
34      stack: error.stack
35    });
36    throw new HttpsError('internal', 'Failed to process order');
37  }
38});

1# Cloud Logging query to find all function errors
2resource.type="cloud_function"
3severity=ERROR
4resource.labels.function_name="processOrder"
5
6# Query to find specific error patterns
7resource.type="cloud_function"
8severity>=WARNING
9jsonPayload.errorCode="PERMISSION_DENIED"