README.md

.NET Client for Apache Kudu

Package

You can get the package on Nuget: https://www.nuget.org/packages/Knet.Kudu.Client

Supported Kudu Versions

This library supports Apache Kudu 1.3 and newer. The newest version of this library should always be used, regardless of the Apache Kudu version. This client tries to maintain feature parity with the official C++ and Java clients.

Quickstart

Docker

Follow the Apache Kudu Quickstart guide to get Kudu running in Docker.

Create a Client

KuduClient client = KuduClient.NewBuilder("localhost:7051,localhost:7151,localhost:7251")
    .Build();

Note: KuduClient is intended to be a singleton. It is inefficient to create multiple clients.

Create a Table

var tableBuilder = new TableBuilder("twitter_firehose")
    .AddColumn("tweet_id", KuduType.Int64, opt => opt.Key(true))
    .AddColumn("user_name", KuduType.String)
    .AddColumn("created_at", KuduType.UnixtimeMicros)
    .AddColumn("text", KuduType.String);

await client.CreateTableAsync(tableBuilder);

See more table options in the wiki.

Open a Table

KuduTable table = await client.OpenTableAsync("twitter_firehose");

Note: This table can be cached and reused concurrently. It simply stores the table schema.

Insert Data

var rows = Enumerable.Range(0, 100).Select(i =>
{
    var row = table.NewInsert();
    row.SetInt64("tweet_id", i);
    row.SetString("user_name", $"user_{i}");
    row.SetDateTime("created_at", DateTime.UtcNow);
    row.SetString("text", $"sample tweet {i}");
    return row;
});

await client.WriteAsync(rows);

Query Data

KuduScanner scanner = client.NewScanBuilder(table)
    .SetProjectedColumns("tweet_id", "user_name", "created_at")
    .Build();

await foreach (ResultSet resultSet in scanner)
{
    Console.WriteLine($"Received {resultSet.Count} rows");

    foreach (RowResult row in resultSet)
    {
        var tweetId = row.GetInt64("tweet_id");
        var userName = row.GetString("user_name");
        var createdAtUtc = row.GetDateTime("created_at");

        Console.WriteLine($"tweet_id: {tweetId}, user_name: {userName}, created_at: {createdAtUtc}");
    }
}

This client includes a simple object mapper,

record Tweet(long TweetId, string Username, DateTime CreatedAt);

var tweets = await scanner.ScanToListAsync<Tweet>();