Added allowlist for Sentry transactions (#19538)

refs
[ARCH-41](https://linear.app/tryghost/issue/ARCH-41/add-allowlist-for-sentry-transactions)

Added allowlist for Sentry transactions so that we can better control
the data we are putting into Sentry

ghost/core/core/shared/sentry.js

@@ -57,6 +57,27 @@ const beforeSend = function (event, hint) {
     }
 };
 
+const ALLOWED_HTTP_TRANSACTIONS = [
+    '/ghost/api',
+    '/members/api'
+].map((path) => {
+    // Sentry names HTTP transactions like: "<HTTP_METHOD> <PATH>" i.e. "GET /ghost/api/content/settings"
+    return new RegExp(`^(GET|POST|PUT|DELETE)\\s(?<path>${path}\\/.+)`);
+});
+
+const beforeSendTransaction = function (event) {
+    // Drop transactions that are not in the allowed list
+    for (const transaction of ALLOWED_HTTP_TRANSACTIONS) {
+        const match = event.transaction.match(transaction);
+
+        if (match?.groups?.path) {
+            return event;
+        }
+    }
+
+    return null;
+};
+
 if (sentryConfig && !sentryConfig.disabled) {
     const Sentry = require('@sentry/node');
     const version = require('@tryghost/version').full;
@@ -72,7 +93,8 @@ if (sentryConfig && !sentryConfig.disabled) {
         environment: environment,
         maxValueLength: 1000,
         integrations: [],
-        beforeSend
+        beforeSend,
+        beforeSendTransaction
     };
 
     // Enable tracing if sentry.tracing.enabled is true
@@ -117,6 +139,7 @@ if (sentryConfig && !sentryConfig.disabled) {
         captureException: Sentry.captureException,
         captureMessage: Sentry.captureMessage,
         beforeSend: beforeSend,
+        beforeSendTransaction: beforeSendTransaction,
         initQueryTracing: (knex) => {
             if (sentryConfig.tracing?.enabled === true) {
                 const integration = new SentryKnexTracingIntegration(knex);

ghost/core/test/unit/shared/sentry.test.js

@@ -155,4 +155,26 @@ describe('UNIT: sentry', function () {
             assert.deepEqual(result, expected);
         });
     });
+
+    describe('beforeTransaction', function () {
+        it('filters transactions based on an allow list', function () {
+            sentry = require('../../../core/shared/sentry');
+
+            const beforeSendTransaction = sentry. beforeSendTransaction;
+
+            const allowedTransactions = [
+                {transaction: 'GET /ghost/api/settings'},
+                {transaction: 'PUT /members/api/member'},
+                {transaction: 'POST /ghost/api/tiers'},
+                {transaction: 'DELETE /members/api/member'}
+            ];
+
+            allowedTransactions.forEach((transaction) => {
+                assert.equal(beforeSendTransaction(transaction), transaction);
+            });
+
+            assert.equal(beforeSendTransaction({transaction: 'GET /foo/bar'}), null);
+            assert.equal(beforeSendTransaction({transaction: 'Some other transaction'}), null);
+        });
+    });
 });