New metric to track oplog queue (#17142)

* New metric to track oplog queue

* Reuse mongo instance from getMongoInfo

app/metrics/server/lib/metrics.js

@@ -5,7 +5,7 @@ import connect from 'connect';
 import _ from 'underscore';
 import { Meteor } from 'meteor/meteor';
 
-import { Info } from '../../../utils';
+import { Info, getOplogInfo } from '../../../utils/server';
 import { Migrations } from '../../../migrations';
 import { settings } from '../../../settings';
 import { Statistics } from '../../../models';
@@ -57,6 +57,7 @@ metrics.version = new client.Gauge({ name: 'rocketchat_version', labelNames: ['v
 metrics.migration = new client.Gauge({ name: 'rocketchat_migration', help: 'migration versoin' });
 metrics.instanceCount = new client.Gauge({ name: 'rocketchat_instance_count', help: 'instances running' });
 metrics.oplogEnabled = new client.Gauge({ name: 'rocketchat_oplog_enabled', labelNames: ['enabled'], help: 'oplog enabled' });
+metrics.oplogQueue = new client.Gauge({ name: 'rocketchat_oplog_queue', labelNames: ['queue'], help: 'oplog queue' });
 metrics.oplog = new client.Counter({
 	name: 'rocketchat_oplog',
 	help: 'summary of oplog operations',
@@ -134,6 +135,9 @@ const setPrometheusData = async () => {
 	metrics.totalPrivateGroupMessages.set(statistics.totalPrivateGroupMessages, date);
 	metrics.totalDirectMessages.set(statistics.totalDirectMessages, date);
 	metrics.totalLivechatMessages.set(statistics.totalLivechatMessages, date);
+
+	const oplogQueue = getOplogInfo().mongo._oplogHandle?._entryQueue?.length || 0;
+	metrics.oplogQueue.set(oplogQueue, date);
 };
 
 const app = connect();

app/utils/server/functions/getMongoInfo.js

@@ -1,12 +1,18 @@
 import { MongoInternals } from 'meteor/mongo';
 
+export function getOplogInfo() {
+	const { mongo } = MongoInternals.defaultRemoteCollectionDriver();
+
+	const oplogEnabled = Boolean(mongo._oplogHandle && mongo._oplogHandle.onOplogEntry);
+
+	return { oplogEnabled, mongo };
+}
+
 function fallbackMongoInfo() {
 	let mongoVersion;
 	let mongoStorageEngine;
 
-	const { mongo } = MongoInternals.defaultRemoteCollectionDriver();
-
-	const oplogEnabled = Boolean(mongo._oplogHandle && mongo._oplogHandle.onOplogEntry);
+	const { oplogEnabled, mongo } = getOplogInfo();
 
 	try {
 		const { version } = Promise.await(mongo.db.command({ buildinfo: 1 }));
@@ -34,9 +40,7 @@ export function getMongoInfo() {
 	let mongoVersion;
 	let mongoStorageEngine;
 
-	const { mongo } = MongoInternals.defaultRemoteCollectionDriver();
-
-	const oplogEnabled = Boolean(mongo._oplogHandle && mongo._oplogHandle.onOplogEntry);
+	const { oplogEnabled, mongo } = getOplogInfo();
 
 	try {
 		const { version, storageEngine } = Promise.await(mongo.db.command({ serverStatus: 1 }));

app/utils/server/index.js

@@ -7,7 +7,7 @@ export { roomTypes } from './lib/roomTypes';
 export { RoomTypeRouteConfig, RoomTypeConfig, RoomSettingsEnum, RoomMemberActions, UiTextContext } from '../lib/RoomTypeConfig';
 export { RoomTypesCommon } from '../lib/RoomTypesCommon';
 export { isDocker } from './functions/isDocker';
-export { getMongoInfo } from './functions/getMongoInfo';
+export { getMongoInfo, getOplogInfo } from './functions/getMongoInfo';
 export { getUserAvatarURL } from '../lib/getUserAvatarURL';
 export { slashCommands } from '../lib/slashCommand';
 export { getUserNotificationPreference } from '../lib/getUserNotificationPreference';

server/startup/serverRunning.js

@@ -6,8 +6,8 @@ import { Meteor } from 'meteor/meteor';
 import { TAPi18n } from 'meteor/rocketchat:tap-i18n';
 
 import { SystemLogger } from '../../app/logger';
-import { settings } from '../../app/settings';
-import { Info, getMongoInfo } from '../../app/utils';
+import { settings } from '../../app/settings/server';
+import { Info, getMongoInfo } from '../../app/utils/server';
 import { Users } from '../../app/models/server';
 import { sendMessagesToAdmins } from '../lib/sendMessagesToAdmins';