feat: relay all CMAP events to MongoClient

The final step in introducing the new pool is to forward all of
the pool events to the MongoClient, so users can listen to the
events there.

Author: mbroadst

lib/cmap/events.js

@@ -127,7 +127,21 @@ class ConnectionPoolClearedEvent extends ConnectionPoolMonitoringEvent {
   }
 }
 
+const CMAP_EVENT_NAMES = [
+  'connectionPoolCreated',
+  'connectionPoolClosed',
+  'connectionCreated',
+  'connectionReady',
+  'connectionClosed',
+  'connectionCheckOutStarted',
+  'connectionCheckOutFailed',
+  'connectionCheckedOut',
+  'connectionCheckedIn',
+  'connectionPoolCleared'
+];
+
 module.exports = {
+  CMAP_EVENT_NAMES,
   ConnectionPoolCreatedEvent,
   ConnectionPoolClosedEvent,
   ConnectionCreatedEvent,

lib/core/sdam/server.js

@@ -1,6 +1,7 @@
 'use strict';
 const EventEmitter = require('events');
 const ConnectionPool = require('../../cmap/connection_pool').ConnectionPool;
+const CMAP_EVENT_NAMES = require('../../cmap/events').CMAP_EVENT_NAMES;
 const MongoError = require('../error').MongoError;
 const relayEvents = require('../utils').relayEvents;
 const BSON = require('../connection/utils').retrieveBSON();
@@ -113,7 +114,12 @@ class Server extends EventEmitter {
     );
 
     this.s.pool = new ConnectionPool(poolOptions);
-    relayEvents(this.s.pool, this, ['commandStarted', 'commandSucceeded', 'commandFailed']);
+    relayEvents(
+      this.s.pool,
+      this,
+      ['commandStarted', 'commandSucceeded', 'commandFailed'].concat(CMAP_EVENT_NAMES)
+    );
+
     this.s.pool.on('clusterTimeReceived', clusterTime => {
       this.clusterTime = clusterTime;
     });

lib/core/sdam/topology.js

@@ -25,6 +25,7 @@ const eachAsync = require('../utils').eachAsync;
 const emitDeprecationWarning = require('../../utils').emitDeprecationWarning;
 const ServerSessionPool = require('../sessions').ServerSessionPool;
 const makeClientMetadata = require('../utils').makeClientMetadata;
+const CMAP_EVENT_NAMES = require('../../cmap/events').CMAP_EVENT_NAMES;
 
 const common = require('./common');
 const drainTimerQueue = common.drainTimerQueue;
@@ -49,7 +50,7 @@ const SERVER_RELAY_EVENTS = [
 
   // NOTE: Legacy events
   'monitoring'
-];
+].concat(CMAP_EVENT_NAMES);
 
 // all events we listen to from `Server` instances
 const LOCAL_SERVER_EVENTS = SERVER_RELAY_EVENTS.concat([

lib/operations/connect.js

@@ -18,6 +18,7 @@ const ServerSessionPool = require('../core').Sessions.ServerSessionPool;
 const emitDeprecationWarning = require('../utils').emitDeprecationWarning;
 const fs = require('fs');
 const BSON = require('../core/connection/utils').retrieveBSON();
+const CMAP_EVENT_NAMES = require('../cmap/events').CMAP_EVENT_NAMES;
 
 let client;
 function loadClient() {
@@ -700,23 +701,28 @@ function mergeOptions(target, source, flatten) {
 
 function relayEvents(mongoClient, topology) {
   const serverOrCommandEvents = [
+    // APM
+    'commandStarted',
+    'commandSucceeded',
+    'commandFailed',
+
+    // SDAM
     'serverOpening',
+    'serverClosed',
     'serverDescriptionChanged',
     'serverHeartbeatStarted',
     'serverHeartbeatSucceeded',
     'serverHeartbeatFailed',
-    'serverClosed',
     'topologyOpening',
     'topologyClosed',
     'topologyDescriptionChanged',
-    'commandStarted',
-    'commandSucceeded',
-    'commandFailed',
+
+    // Legacy
     'joined',
     'left',
     'ping',
     'ha'
-  ];
+  ].concat(CMAP_EVENT_NAMES);
 
   serverOrCommandEvents.forEach(event => {
     topology.on(event, (object1, object2) => {