how to use conn.db.admin().command() on secondary in replica set? - mongodb

Trying to get results of command that I passed in admin command,
but it throws me back a MongoError
how to/ where to set rs.slaveOk() using mongoose lib, if its ?
conn = mongoose.createConnection(`mongodb://localhost:port`)
cmd = "someCommand"
conn.db.admin().command(cmd, (err, result)=>{
if(err){
console.error(err)
}
resolve(result)
})
// MongoError: not master and slaveOk=false

Added Read Preference and Replicaset name in Connection String
https://mongoosejs.com/docs/connections.html#connection-string-options
https://mongoosejs.com/docs/api.html#query_Query-read
var options = {
"db": {
"readPreference": "secondaryPreferred"
},
"replset": {
"rs_name": "replica_name",
}
}
var connection =
mongoose.createConnection(`mongodb://localhost:27030/dbname`, options);

Related

Unable to connect to Mongodb Atlas using mongoose

I am trying to connect to a cluster created in Mongodb Atlas using mongoose in node js and I am facing below issues when doing so.
When I use the connection string that is given in the Mongo db atlasmongodb+srv://lm_dev_app:<password>#lmdev-q5biw.mongodb.net/test?retryWrites=true&w=majorityI get below error
{ Error: queryTxt EBADNAME lmdev-q5biw.mongodb.net
at QueryReqWrap.onresolve [as oncomplete] (dns.js:196:19)
errno: 'EBADNAME',
code: 'EBADNAME',
syscall: 'queryTxt',
hostname: 'lmdev-q5biw.mongodb.net'}
I cannot use this connection string in Mongodb Compass as well as I am getting the same error there.
If I try to connect using mongodb://lm_dev_app:<password>#lmdev-shard-00-01-q5biw.mongodb.net/test i get below error
MongooseServerSelectionError: connection to 54.66.221.230:27017 closed
However I am able to connect to each node using Mongodb Compass which eliminates the possibility of my ipaddress not being whitelisted.
Here is the sample code that I am using
const mongoosePromise = mongoose.connect("mongodb://lm_dev_app:<password>#lmdev-shard-00-01-q5biw.mongodb.net/test", {
useNewUrlParser: true,
useUnifiedTopology: true,
replicaSet: "LMDEV"
}, (err) => {
if (err) {
console.log(err);
} else {
console.log("Successful");
}
});
Any thoughts on what is happening here.
There are couple of things that I need to highlight here.
The default connection string that is shown in Mongodb Atlas seems to be wrong. It shows you mongodb+srv://<username>:<password>#<cluster_url>/test?retryWrites=true&w=majority. But I used mongodb://<username>:<password>#<node_url>:27017/ to make it work. You can also use mongodb://<username>:<password>#<node_url>:27017/admin.
Pass ssl:true in the options that we are passing.
Finally one of the 3 options can be used to connect to the database.
a. const mongoosePromise = mongoose.connect("mongodb://lm_dev_app:<password>#lmdev-shard-00-01-q5biw.mongodb.net:27017/", {
useNewUrlParser: true,
useUnifiedTopology: true,
authSource:"admin",
ssl: true,
}, (err) => {
if (err) {
console.log(err);
} else {
console.log("Successful");
}
});
b. const mongoosePromise = mongoose.connect("mongodb://lm_dev_app:<password>#lmdev-shard-00-01-q5biw.mongodb.net:27017/", {
useNewUrlParser: true,
useUnifiedTopology: true,
authSource:"admin",
ssl: true,
}, (err) => {
if (err) {
console.log(err);
} else {
console.log("Successful");
}
});
c. const mongoosePromise = mongoose.connect("mongodb://lm_dev_app:<password>#lmdev-shard-00-01-q5biw.mongodb.net:27017/admin", {
useNewUrlParser: true,
useUnifiedTopology: true,
ssl: true,
}, (err) => {
if (err) {
console.log(err);
} else {
console.log("Successful");
}
});
EDIT 1:
After having a chat with Atlas support team I was told that issue in point 1 is due to DNS resolution issue with my service provider. So i have changed my DNS settings to point to a public DNS server.
After trying different connection strings for several hours, I finally just copy/pasted the connection string from MongoDB Compass and it works! (first connect, then edit the connection string as it will change)
It looks like this:
mongodb+srv://username:password#fra-atlas-shard.abcde.mongodb.net/test?authSource=admin&replicaSet=atlas-abcde-shard-0&readPreference=primary&appname=MongoDB%20Compass&ssl=true

AWS Lambda timing out on MongoDB Atlas connection

I'm just trying to write a simple Lambda function to insert data into my MongoDB Atlas cluster. I've set the cluster to accept all incoming traffic (0.0.0.0/0) and confirmed that I can connect locally.
For AWS Lambda, I set up a VPC using the VPC wizard, and I gave my Lambda function a security role with full admin access. I set the timeout to 12 seconds, but I'm still getting the following error:
Response:
{
"errorMessage": "2018-11-19T15:17:23.200Z 3048e1fd-ec0e-11e8-a03d-fb79584484c5 Task timed out after 11.01 seconds"
}
Request ID:
"3048e1fd-ec0e-11e8-a03d-fb79584484c5"
Function Logs:
START RequestId: 3048e1fd-ec0e-11e8-a03d-fb79584484c5 Version: $LATEST
2018-11-19T15:17:12.191Z 3048e1fd-ec0e-11e8-a03d-fb79584484c5 Calling MongoDB Atlas from AWS Lambda with event: {"address":{"street":"2 Avenue","zipcode":"10075","building":"1480","coord":[-73.9557413,40.7720266]},"borough":"Manhattan","cuisine":"Italian","grades":[{"date":"2014-10-01T00:00:00Z","grade":"A","score":11},{"date":"2014-01-16T00:00:00Z","grade":"B","score":17}],"name":"Vella","restaurant_id":"41704620"}
2018-11-19T15:17:12.208Z 3048e1fd-ec0e-11e8-a03d-fb79584484c5 => connecting to database
2018-11-19T15:17:12.248Z 3048e1fd-ec0e-11e8-a03d-fb79584484c5 (node:1) DeprecationWarning: current URL string parser is deprecated, and will be removed in a future version. To use the new parser, pass option { useNewUrlParser: true } to MongoClient.connect.
END RequestId: 3048e1fd-ec0e-11e8-a03d-fb79584484c5
REPORT RequestId: 3048e1fd-ec0e-11e8-a03d-fb79584484c5 Duration: 11011.08 ms Billed Duration: 11000 ms Memory Size: 128 MB Max Memory Used: 29 MB
2018-11-19T15:17:23.200Z 3048e1fd-ec0e-11e8-a03d-fb79584484c5 Task timed out after 11.01 seconds
The relevant part of my code for connecting is (with user and pass being the appropriate values):
const MongoClient = require('mongodb').MongoClient;
let atlas_connection_uri = "mongodb+srv://<user>:<pass>#restaurantcluster-2ylyf.gcp.mongodb.net/testdb"
let cachedDb = null;
exports.handler = (event, context, callback) => {
var uri = atlas_connection_uri
if (atlas_connection_uri != null) {
processEvent(event, context, callback);
}
else {
atlas_connection_uri = uri;
console.log('the Atlas connection string is ' + atlas_connection_uri);
processEvent(event, context, callback);
}
};
function processEvent(event, context, callback) {
console.log('Calling MongoDB Atlas from AWS Lambda with event: ' + JSON.stringify(event));
var jsonContents = JSON.parse(JSON.stringify(event));
//date conversion for grades array
if(jsonContents.grades != null) {
for(var i = 0, len=jsonContents.grades.length; i < len; i++) {
jsonContents.grades[i].date = new Date();
}
}
context.callbackWaitsForEmptyEventLoop = false;
try {
if (cachedDb == null) {
console.log('=> connecting to database');
MongoClient.connect(atlas_connection_uri, function (err, client) {
cachedDb = client.db('testdb');
return createDoc(cachedDb, jsonContents, callback);
});
}
else {
createDoc(cachedDb, jsonContents, callback);
}
}
catch (err) {
console.error('an error occurred', err);
}
}
I suspect that something is going on with my VPC firewall/permissions/security group considering the fact that I can connect from my local machine, but I have no idea how that could be the case when I'm granting full admins privileges in my security role and I've set all outgoing VPC traffic to my public subnet.
I would appreciate any advice/help in solving this!
edit to provide more info:
The function console.logs '=> connecting to database' and then immediately times out at MongoClient.connect (confirmed by attempting to console.log directly after that).

ConnectionError: Connection lost - read ECONNRESET in protractor

I am using protractor 52.2 and cucumber 3.2.2. I am using selenium grid(selenium-server-standalone-3.14.0.jar) with the protractor and running my script in 4 browsers of 4 different nodes. I have a table of 600 rows in the DB. Initially, I am accessing data from this table and entering the data of each row through my protractor script and updating the DB column after successful entering of each row. But after entering some rows successfully, protractor script abruptly ends with error "ConnectionError: Connection lost - read ECONNRESET in protractor".And I am getting an error message in update SQL query, that "RequestError: Resource ID: 1. The request limit for the database is 60 and has been reached. See 'http://go.microsoft.com/fwlink/?LinkId=267637' for assistance." The update query which I am using is given below(i am using azure sql). I am not getting a clear idea of how to solve this. Thanks in advance.
var Connection = require('tedious').Connection;
var Request = require('tedious').Request;
var config =
{
userName: 'xxx',
password: 'xxxxx',
server: 'xxxxxx',
options:
{
database: 'xxx' ,
encrypt: true,
rowCollectionOnRequestCompletion: true
}
}
var connection = new Connection(config);
defineSupportCode(function ({ setDefaultTimeout, Given, When, Then }) {
setDefaultTimeout(30000 * 1000);
function updatedb(LPAID){
request = new Request("UPDATE COM_Location_Post with (rowlock) SET IsPublished = 1 WHERE Id ="+LPAID,function(err,rowCount, rows) {
if(err){
console.log(err)
}
});
connection.execSql(request);
}
});
You did not use connection close in your script.
By your question its clear after max instance you face this problem.
Try closing your connection every time for each transaction.
(async () => {
const config = {
user: 'User',
password: 'iPg$',
server: 'cp-sql',
database: 'DBI',
options: {
encrypt: true // Use this if you're on Windows Azure
}
}
try {
let pool = await sql.connect(config)
var envcode, testcode;
let result1 = await pool.request()
.query(`query 1 goes here`)
// console.dir(result1)
pool.close();
sql.close();
let pool1 = await sql.connect(config)
let result2 = await pool1.request()
.query(`query 2 goes here`)
// console.dir(result2)
pool1.close();
sql.close();
resolve(result2);
} catch (err) {
console.log(err)
}
})()

'Must specify set name for replica set ConnectionStrings' when using copydb

I am writing a nodejs script that allows me to copy an entire database to a specified destination host. For this I am using the command copydb.
However I am getting the Error as written above.
I am not sure what to do as I am not using replicas in any way and am not entirely fond of how to use them either. All I want to do is copy the db from source host to destination.
Here is the code:
function copydb(_sourceUrl, _destinationUrl, _db, _sourceAdminUsername, _sourceAdminPassword) {
return new Promise((resolve, reject) => {
mongoClient.connect(_destinationUrl + "/" + _db)
.then(destinationDB => {
destinationDB.admin().command({
copydb: 1,
fromhost: _sourceUrl,
fromdb: _db,
username: _sourceAdminUsername,
todb: _db,
nonce: "some-nonce",
key: {
username: _sourceAdminUsername,
password: _sourceAdminPassword
}
}, function (err, res) {
if (err) {
reject(err)
} else {
resolve(res)
}
destinationDB.close();
})
}).catch(err => reject(err))
})
}
The values I am passing are like so:
_sourceUrl: "mongodb://myhost"
_desinationUrl: "mongodb://adminuser:adminpassword#localhost:27017"
_db: "testdb",
_sourceAdminUsername: adminUsername
_sourceAdminPassword: adminPassword
PS: I am not sure what to use as nonce field, neither key

Reliably reconnect to MongoDB

UPDATE: I am using the 2.1 version on the driver, against 3.2
I have a node application that uses MongoDB. The problem I have is that if the MongoDB server goes down for any reason, the application doesn't reconnect.
To get this right, I based my tests on the code in this official tutorial.
var MongoClient = require('mongodb').MongoClient
, f = require('util').format;
MongoClient.connect('mongodb://localhost:27017/test',
// Optional: uncomment if necessary
// { db: { bufferMaxEntries: 3 } },
function(err, db) {
var col = db.collection('t');
setInterval(function() {
col.insert({a:1}, function(err, r) {
console.log("insert")
console.log(err)
col.findOne({}, function(err, doc) {
console.log("findOne")
console.log(err)
});
})
}, 1000)
});
The idea is to run this script, and then stop mongod, and then restart it.
So, here we go:
TEST 1: stopping mongod for 10 seconds
Stopping MongoDb for 10 seconds does the desired result: it will stop running the queries for those 10 seconds, and then will run all of them once the server is back ip
TEST 2: stopping mongod for 30 seconds
After exactly 30 seconds, I start getting:
{ [MongoError: topology was destroyed] name: 'MongoError', message: 'topology was destroyed' }
insert
{ [MongoError: topology was destroyed] name: 'MongoError', message: 'topology was destroyed' }
The trouble is that from this on, when I restart mongod, the connection is not re-establised.
Solutions?
Does this problem have a solution? If so, do you know what it is?
Once my app starts puking "topology was destroyed", the only way to get everything to work again is by restarting the whole app...
There are 2 connection options that control how mongo nodejs driver reconnects after connection fails
reconnectTries: attempt to reconnect #times (default 30 times)
reconnectInterval: Server will wait # milliseconds between retries
(default 1000 ms)
reference on mongo driver docs
Which means that mongo will keep trying to connect 30 times by default and wait 1 second before every retry. Which is why you start seeing errors after 30 seconds.
You should tweak these 2 parameters based on you needs like this sample.
var MongoClient = require('mongodb').MongoClient,
f = require('util').format;
MongoClient.connect('mongodb://localhost:27017/test',
{
// retry to connect for 60 times
reconnectTries: 60,
// wait 1 second before retrying
reconnectInterval: 1000
},
function(err, db) {
var col = db.collection('t');
setInterval(function() {
col.insert({
a: 1
}, function(err, r) {
console.log("insert")
console.log(err)
col.findOne({}, function(err, doc) {
console.log("findOne")
console.log(err)
});
})
}, 1000)
});
This will try 60 times instead of the default 30, which means that you'll start seeing errors after 60 seconds when it stops trying to reconnect.
Sidenote: if you want to prevent the app/request from waiting until the expiration of the reconnection period you have to pass the option bufferMaxEntries: 0. The price for this is that requests are also aborted during short network interruptions.
package.json: "mongodb": "3.1.3"
Reconnect existing connections
To fine-tune the reconnect configuration for pre-established connections, you can modify the reconnectTries/reconnectInterval options (default values and further documentation here).
Reconnect initial connection
For the initial connection, the mongo client does not reconnect if it encounters an error (see below). I believe it should, but in the meantime, I've created the following workaround using the promise-retry library (which uses an exponential backoff strategy).
const promiseRetry = require('promise-retry')
const MongoClient = require('mongodb').MongoClient
const options = {
useNewUrlParser: true,
reconnectTries: 60,
reconnectInterval: 1000,
poolSize: 10,
bufferMaxEntries: 0
}
const promiseRetryOptions = {
retries: options.reconnectTries,
factor: 1.5,
minTimeout: options.reconnectInterval,
maxTimeout: 5000
}
const connect = (url) => {
return promiseRetry((retry, number) => {
console.log(`MongoClient connecting to ${url} - retry number: ${number}`)
return MongoClient.connect(url, options).catch(retry)
}, promiseRetryOptions)
}
module.exports = { connect }
Mongo Initial Connect Error: failed to connect to server [db:27017] on first connect
By default the Mongo driver will try to reconnect 30 times, one every second. After that it will not try to reconnect again.
You can set the number of retries to Number.MAX_VALUE to keep it reconnecting "almost forever":
var connection = "mongodb://127.0.0.1:27017/db";
MongoClient.connect(connection, {
server : {
reconnectTries : Number.MAX_VALUE,
autoReconnect : true
}
}, function (err, db) {
});
With mongodb driver 3.1.10, you can set up your connection as
MongoClient.connect(connectionUrl, {
reconnectInterval: 10000, // wait for 10 seconds before retry
reconnectTries: Number.MAX_VALUE, // retry forever
}, function(err, res) {
console.log('connected')
})
You do not have to specify autoReconnect: true as that's the default.
It's happening because it might have crossed the retry connection limit. After number of retries it destroy the TCP connection and become idle. So for it increase the number of retries and it would be better if you increase the gap between connection retry.
Use below options:
retryMiliSeconds {Number, default:5000}, number of milliseconds between retries.
numberOfRetries {Number, default:5}, number of retries off connection.
For more details refer to this link https://mongodb.github.io/node-mongodb-native/driver-articles/mongoclient.html
Solution:
MongoClient.connect("mongodb://localhost:27017/integration_test_?", {
db: {
native_parser: false,
retryMiliSeconds: 100000,
numberOfRetries: 100
},
server: {
socketOptions: {
connectTimeoutMS: 500
}
}
}, callback)
Behavior may differ with different versions of driver. You should mention your driver version.
driver version : 2.2.10 (latest)
mongo db version : 3.0.7
Below code will extend the time mongod can take to come back up.
var MongoClient = require('mongodb').MongoClient
, f = require('util').format;
function connectCallback(err, db) {
var col = db.collection('t');
setInterval(function() {
col.insert({a:1}, function(err, r) {
console.log("insert")
console.log(err)
col.findOne({}, function(err, doc) {
console.log("findOne")
console.log(err)
});
})
}, 1000)
}
var options = { server: { reconnectTries: 2000,reconnectInterval: 1000 }}
MongoClient.connect('mongodb://localhost:27017/test',options,connectCallback);
2nd argument can be used to pass server options.
If you was using Mongoose for your Schemas, it would be worth considering my option below since mongoose was never retrying to reconnect to mongoDB implicitly after first attempt failed.
Kindly note I am connecting to Azure CosmosDB for MongoDB API. On yours maybe on the local machine.
Below is my code.
const mongoose = require('mongoose');
// set the global useNewUrlParser option to turn on useNewUrlParser for every connection by default.
mongoose.set('useNewUrlParser', true);
// In order to use `findOneAndUpdate()` and `findOneAndDelete()`
mongoose.set('useFindAndModify', false);
async function mongoDbPool() {
// Closure.
return function connectWithRetry() {
// All the variables and functions in here will Persist in Scope.
const COSMODDBUSER = process.env.COSMODDBUSER;
const COSMOSDBPASSWORD = process.env.COSMOSDBPASSWORD;
const COSMOSDBCONNSTR = process.env.COSMOSDBCONNSTR;
var dbAuth = {
auth: {
user: COSMODDBUSER,
password: COSMOSDBPASSWORD
}
};
const mongoUrl = COSMOSDBCONNSTR + '?ssl=true&replicaSet=globaldb';
return mongoose.connect(mongoUrl, dbAuth, (err) => {
if (err) {
console.error('Failed to connect to mongo - retrying in 5 sec');
console.error(err);
setTimeout(connectWithRetry, 5000);
} else {
console.log(`Connected to Azure CosmosDB for MongoDB API.`);
}
});
};}
You may decide to export and reuse this module everywhere you need to connect to db via Dependency Injection. But instead I will only show how to access the database connection for now.
(async () => {
var dbPools = await Promise.all([mongoDbPool()]);
var mongoDbInstance = await dbPools[0]();
// Now use "mongoDbInstance" to do what you need.
})();