Written May 3, 2014

HBase, Thrift & C# - First Connections

I seemingly have a bad habit of never writing part two of a series. So to buck the trend, this piece is a follow up to NuGet Servers, HBase, Thrift Code Generation and one sweet Jenkins CI Build. You don’t need to read the whole post; but, familiarizing yourself with section III and on is important. Don’t forget to check other posts in this series.

Let’s take a quick look at establishing connectivity to our HBase Thrift server. The example connection code in the thrift C# solution is a great primer and what we will use as the base here.

For the majority of the code in the rest of this series, we will take a simplistic page from NHibernate’s architecture. Let’s start with a simple Interface called ISession which implements IDisposable. The implementation of IDisposable is so we can build sessions within a using statement, letting the framework do our heavy lifting.

Further, we will build a class called Session that implements the Interface ISession. Its constructor will take a reference to our Pool Manager class and will take a Connection object that has configuration data in it.

public class Session : ISession
    private readonly IConnection _connection;
    private readonly ISessionPoolManager _manager;
    private readonly TSocket _transport;
    private Hbase.Hbase.Client _client; 
    public Session(ISessionPoolManager manager, IConnection connection)
         Guid = Guid.NewGuid(); 
         _connection = connection; 
         _manager = manager; 
         _transport = new TSocket(Connection.Name, Connection.Port);
         var protocol = new TBinaryProtocol(_transport);
         _client = new Hbase.Hbase.Client(protocol);

The class has a private method called OpenConnection() that is used to, well, open a connection to HBase via Thrift. This code is very straight forward:

private Hbase.Hbase.Client OpenConnection()
     IsConnected = _transport.IsOpen; 
     return _client; 

For completeness let’s implement a CloseConnection():

private void CloseConnection()
      IsConnected = _transport.IsOpen; 

Because the Session class implements the IDisposable interface we are required to have a Dispose method. The Dispose method calls our internal close on the transport and re-queues this object in Pool Manager’s queue.

public void Dispose()

In the next article we will look at implementing a table scanner for HBase and the structure to support it.