CODEWITHSUNDEEP
javamongodb
Lugaru
Lugaru

Reputation: 1460

MongoDB: check connection to DB

I'm looking for best way to check connection to Mongo DB. Situation: client makes request (api) to server. And server returns status of all databases.

What the best way to do it?

Upvotes: 10

Views: 40165

Answers (6)

gifpif
gifpif

Reputation: 4917

The ping command is a no-op used to test whether a server is responding to commands. This command will return immediately even if the server is write-locked:

try {
    DBObject ping = new BasicDBObject("ping", "1");
    mongoTemplate.getDb().getMongo().getDB("DATABASE NAME").command(ping);
} catch (Exception exp) {
    // MongoDb is down..
}

Upvotes: 6

plswork04
plswork04

Reputation: 659

Answering: How do I check that my MongoClient connected to my db?

As has already been pointed out, the getting started documentation uses the ping command.

Packaged as a function:

/**
 * Try to detect if the given MongoDatabase successfully connected to a Mongo
 * instance.
 * 
 * Will block up to the client's socket settings timeout, e.g. 30000 ms.
 * 
 * Returning true indicates that future uses of the given client will probably
 * succeed,
 * but the connection is not guaranteed as connection state may change.
 * 
 * @param database
 * @return the present connection state
 */
static boolean isConnected(MongoDatabase database) {
    Bson command = new BsonDocument("ping", new BsonInt64(1));
    try {
        database.runCommand(command);
    } catch (MongoTimeoutException e) {
        return false;
    }
    return true;

}

/**
 * Try to detect if the given MongoClient successfully connected to a Mongodb
 * instance.
 * 
 * Will block up to the client's socket settings timeout, e.g. 30000 ms.
 * 
 * Returning true indicates that future uses of the given client will probably
 * succeed,
 * but the connection is not guaranteed as connection state may change.
 * 
 * @param mongoClient
 * @return the present connection state
 */
static boolean isConnected(MongoClient mongoClient) {
    return isConnected(mongoClient.getDatabase("admin"));
}

mongoClient.listDatabaseNames().first(); would also work, but that would just run the listDatabases command against the admin database. So manually writing the ping command is slightly better.

After running a command, mongoClient.getClusterDescription() will return a meaningful result, but it does not block or wait, so calling it right after creating a MongoClient instance will not return an actionable response.

If you need more control, look at the answer using ServerMonitorListener.

This answer is valid as of/for 'org.mongodb:mongodb-driver-sync:4.9.1'

Upvotes: 1

Md Samiul Alim Sakib
Md Samiul Alim Sakib

Reputation: 1114

In Java MongoDriver 3.3.0 use ServerMonitorListener to determine whether server is up and connected or not. Here is the example code,

public class ServerConnection implements ServerMonitorListener {
    private MongoClient client;

    public ServerConnection(){
        try {
            MongoClientOptions clientOptions = new MongoClientOptions.Builder()
                .addServerMonitorListener(this)
                .build();

            client = new MongoClient(new ServerAddress("localhost", 27017), clientOptions);
        } catch (Exception ex) {

        }
    }

    @Override
    public void serverHearbeatStarted(ServerHeartbeatStartedEvent serverHeartbeatStartedEvent) {
        // Ping Started
    }

    @Override
    public void serverHeartbeatSucceeded(ServerHeartbeatSucceededEvent serverHeartbeatSucceededEvent) {
        // Ping Succeed, Connected to server
    }

    @Override
    public void serverHeartbeatFailed(ServerHeartbeatFailedEvent serverHeartbeatFailedEvent) {
        // Ping failed, server down or connection lost
    }
}

Upvotes: 7

rupweb
rupweb

Reputation: 3328

I use this:

Builder o = MongoClientOptions.builder().connectTimeout(3000);  
MongoClient mongo = new MongoClient(new ServerAddress("192.168.0.1", 3001), o.build());    

try {
  mongo.getAddress();
} catch (Exception e) {
  System.out.println("Mongo is down");
  mongo.close();
  return;
}

Upvotes: 8

ninehundreds
ninehundreds

Reputation: 1105

If I understand your question correctly you want to get state returned via a web service call. You can write a function that invokes db.serverStatus() and have it return the data. Check out the documentation here:

Monitoring for MongoDB

Upvotes: 2

raffian
raffian

Reputation: 32076

Use MongoClient for Java, all the info you need is here...

http://docs.mongodb.org/ecosystem/tutorial/getting-started-with-java-driver/

Upvotes: 2

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