fix: add mongodb connection pool patch (#3665)

.tav.yml

@@ -144,22 +144,22 @@ mongodb-core:
 mongodb-3:
   name: mongodb
   versions: '>=3.3 <4'
-  commands: node test/instrumentation/modules/mongodb.test.js
+  commands: node test/instrumentation/modules/mongodb/mongodb.test.js
 mongodb-4:
   name: mongodb
   versions: '>=4 <5'
   node: '>=12.9.0'
-  commands: node test/instrumentation/modules/mongodb.test.js
+  commands: node test/instrumentation/modules/mongodb/mongodb.test.js
 mongodb-5:
   name: mongodb
   versions: '>=5 <6'
   node: '>=14.20.1'
-  commands: node test/instrumentation/modules/mongodb.test.js
+  commands: node test/instrumentation/modules/mongodb/mongodb.test.js
 mongodb:
   name: mongodb
   versions: '>=6 <7'
   node: '>=15.0.0'
-  commands: node test/instrumentation/modules/mongodb.test.js
+  commands: node test/instrumentation/modules/mongodb/mongodb.test.js
 
 # Bluebird is effectively deprecated (https://github.com/petkaantonov/bluebird#%EF%B8%8Fnote%EF%B8%8F).
 # Testing the full set of supported bluebird releases (`>=2 <4`) is currently

CHANGELOG.asciidoc

@@ -56,6 +56,10 @@ See the <<upgrade-to-v4>> guide.
 [float]
 ===== Bug fixes
 
+* Fix `mongodb` instrumentation to avoid loosing context when multiple cursors
+  are running concurrently. ({issues}3161[#3161])
+
+
 [float]
 ===== Chores
 

lib/instrumentation/index.js

@@ -92,6 +92,10 @@ var MODULE_PATCHERS = [
   { modPath: 'mimic-response' },
   { modPath: 'mongodb-core' },
   { modPath: 'mongodb' },
+  {
+    modPath: 'mongodb/lib/cmap/connection_pool.js',
+    patcher: './modules/mongodb/lib/cmap/connection_pool.js',
+  },
   { modPath: 'mysql' },
   { modPath: 'mysql2' },
   { modPath: 'next' },

lib/instrumentation/modules/mongodb/lib/cmap/connection_pool.js

@@ -0,0 +1,39 @@
+/*
+ * Copyright Elasticsearch B.V. and other contributors where applicable.
+ * Licensed under the BSD 2-Clause License; you may not use this file except in
+ * compliance with the BSD 2-Clause License.
+ */
+
+'use strict';
+
+const { AsyncResource } = require('async_hooks');
+
+const semver = require('semver');
+
+module.exports = (mod, agent, { version, enabled }) => {
+  if (!enabled) return mod;
+  if (!semver.satisfies(version, '>=3.3 <7.0')) {
+    agent.logger.debug(
+      'mongodb version %s not instrumented (mongodb <3.3 is instrumented via mongodb-core)',
+      version,
+    );
+    return mod;
+  }
+
+  if (mod.ConnectionPool) {
+    class ConnectionPoolTraced extends mod.ConnectionPool {
+      checkOut(callback) {
+        return super.checkOut(AsyncResource.bind(callback));
+      }
+    }
+
+    Object.defineProperty(mod, 'ConnectionPool', {
+      enumerable: true,
+      get: function () {
+        return ConnectionPoolTraced;
+      },
+    });
+
+    return mod;
+  }
+};

test/_is_mongodb_incompat.js

@@ -7,6 +7,7 @@
 'use strict';
 
 var semver = require('semver');
+const { safeGetPackageVersion } = require('./_utils');
 
 /**
  * Return whether the current 'mongodb' version is incompatible with the
@@ -26,7 +27,7 @@ var semver = require('semver');
  */
 function isMongodbIncompat() {
   const nodeVer = process.version;
-  const mongodbVer = require('mongodb/package.json').version;
+  const mongodbVer = safeGetPackageVersion('mongodb');
   const msg = `mongodb@${mongodbVer} is incompatible with node@${nodeVer}`;
 
   if (semver.satisfies(mongodbVer, '4.x')) {