MongoDB Driver 2.0 C# is there a way to find out if the server is down? In the new driver how do we run the Ping command?

Question

How do you call the Ping command with the new C# driver 2.0?
In the old driver it was available via Server.Ping()? Also, Is there a way to find out if the server is running/responding without running the actual query?
Using mongoClient.Cluster.Description.State doesn't help because it still gave the disconnected state even after the mongo server started responding.

possible duplicate of [MongoServer.State equivalent in the 2.0 driver](http://stackoverflow.com/questions/29459990/mongoserver-state-equivalent-in-the-2-0-driver) — i3arnon, Jun 08 '15 at 15:47
why would you use ping instead of a controlled connection timeout? If you have an high ping, when you will connect to the server your "total time to connect to the db" will be doubled (ping time + real connection time) — Gianni B., Jun 08 '15 at 15:53
mongoClient.Cluster.Description.State is not reliable - noticed even after the server was back we were getting the state as disconnected. I was hoping to use the Ping to check the quick connectivity test and throw exceptions and not proceed to the query to differeniate connectivity exceptions vs occasional query/command timeout because of delayed return the response due to number of records. — Heena Patel, Jun 08 '15 at 17:53

score 3 · Answer 1 · answered Jun 08 '15 at 15:50

3

You can check the cluster's status using its Description property:

var state = _client.Cluster.Description.State

If you want a specific server out of that cluster you can use the Servers property:

var state = _client.Cluster.Description.Servers.Single().State;

answered Jun 08 '15 at 15:50

i3arnon

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I tried that but even after the server came online the state was coming back as Disconnected. – Heena Patel Jun 08 '15 at 17:39
@HeenaPatel AFAIK the this reflects the status of the last operation. To actually check the connection you need to make an active operation and see if it fails. – i3arnon Jun 08 '15 at 17:41
1

mongoClient.Cluster.Description.State is not reliable - noticed even after the server was back we were getting the state as disconnected. I was hoping to use the Ping to check the quick connectivity test and throw exceptions and not proceed to the query to differentiate connectivity exceptions vs occasional query/command timeout because of delayed return the response due to number of records. – Heena Patel Jun 08 '15 at 17:59
There is no Cluster property under Client when specifying a connection string. (v2.0.1.27) – Adam Reed Aug 06 '15 at 16:05
@AdamReed yes, there is. – i3arnon Aug 06 '15 at 16:15
@AdamReed does your `_client` data member happen to be declared as `IMongoClient` instead of `MongoClient`? (good theme though) – i3arnon Aug 06 '15 at 18:44
@AdamReed don't really know what to tell you. I see it on my machine and [in the repository on GitHub](https://github.com/mongodb/mongo-csharp-driver/blob/master/src/MongoDB.Driver/MongoClient.cs#L83) (where it is for almost a year): – i3arnon Aug 06 '15 at 21:09

score 2 · Answer 2 · answered Sep 04 '15 at 08:52

This worked for me on both c# driver 2 and 1

int count = 0;
var client = new MongoClient(connection);
        // This while loop is to allow us to detect if we are connected to the MongoDB server
        // if we are then we miss the execption but after 5 seconds and the connection has not
        // been made we throw the execption.
        while (client.Cluster.Description.State.ToString() == "Disconnected") {
            Thread.Sleep(100);
            if (count++ >= 50) {
                throw new Exception("Unable to connect to the database. Please make sure that "
                    + client.Settings.Server.Host + " is online");
            }
        }

score 0 · Answer 3 · answered Dec 21 '16 at 13:32

As @i3arnon's answer I can tell it was reliable for me in this way:

var server = client.Cluster.Description.Servers.FirstOrDefault();
var serverState = ServerState.Disconnected;
if (server != null) serverState = server.State;

or in new versions of .Net

var serverState = client.Cluster.Description.Servers.FirstOrDefault()?.State 
    ?? ServerState.Disconnected;

But if you realy want to run a ping command you can do it like this:

var command = new CommandDocument("ping", 1);
try
{
    db.RunCommand<BsonDocument>(command);
}
catch (Exception ex)
{
    // ping failed
}

MongoDB Driver 2.0 C# is there a way to find out if the server is down? In the new driver how do we run the Ping command?

3 Answers3

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