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?

问题

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.

回答1:

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;

回答2:

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");
            }
        }

回答3:

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
}

来源：https://stackoverflow.com/questions/30713599/mongodb-driver-2-0-c-sharp-is-there-a-way-to-find-out-if-the-server-is-down-in