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Mobius: C# API for Spark

Mobius provides C# language binding to Apache Spark enabling the implementation of Spark driver program and data processing operations in the languages supported in the .NET framework like C# or F#.

For example, the word count sample in Apache Spark can be implemented in C# as follows :

var lines = sparkContext.TextFile(@"hdfs://path/to/input.txt");  
var words = lines.FlatMap(s => s.Split(' '));
var wordCounts = words.Map(w => new KeyValuePair<string, int>(w.Trim(), 1))  
                      .ReduceByKey((x, y) => x + y);  
var wordCountCollection = wordCounts.Collect();  

A simple DataFrame application using TempTable may look like the following:

var reqDataFrame = sqlContext.TextFile(@"hdfs://path/to/requests.csv");
var metricDataFrame = sqlContext.TextFile(@"hdfs://path/to/metrics.csv");
// C0 - guid in requests DataFrame, C3 - guid in metrics DataFrame  
var joinDataFrame = GetSqlContext().Sql(  
    "SELECT joinedtable.datacenter" +
         ", MAX(joinedtable.latency) maxlatency" +
         ", AVG(joinedtable.latency) avglatency " +
    "FROM (" +
       "SELECT a.C1 as datacenter, b.C6 as latency " +  
       "FROM requests a JOIN metrics b ON a.C0  = b.C3) joinedtable " +   
    "GROUP BY datacenter");

A simple DataFrame application using DataFrame DSL may look like the following:

// C0 - guid, C1 - datacenter
var reqDataFrame = sqlContext.TextFile(@"hdfs://path/to/requests.csv")  
                             .Select("C0", "C1");    
// C3 - guid, C6 - latency   
var metricDataFrame = sqlContext.TextFile(@"hdfs://path/to/metrics.csv", ",", false, true)
                                .Select("C3", "C6"); //override delimiter, hasHeader & inferSchema
var joinDataFrame = reqDataFrame.Join(metricDataFrame, reqDataFrame["C0"] == metricDataFrame["C3"])
var maxLatencyByDcDataFrame = joinDataFrame.Agg(new Dictionary<string, string> { { "C6", "max" } });

A simple Spark Streaming application that processes messages from Kafka using C# may be implemented using the following code:

StreamingContext sparkStreamingContext = StreamingContext.GetOrCreate(checkpointPath, () =>
      var ssc = new StreamingContext(sparkContext, slideDurationInMillis);
      var stream = KafkaUtils.CreateDirectStream(ssc, topicList, kafkaParams, perTopicPartitionKafkaOffsets);
      //message format: [timestamp],[loglevel],[logmessage]
      var countByLogLevelAndTime = stream
                                    .Map(kvp => Encoding.UTF8.GetString(kvp.Value))
                                    .Filter(line => line.Contains(","))
                                    .Map(line => line.Split(','))
                                    .Map(columns => new KeyValuePair<string, int>(
                                                          string.Format("{0},{1}", columns[0], columns[1]), 1))
                                    .ReduceByKeyAndWindow((x, y) => x + y, (x, y) => x - y,
                                                          windowDurationInSecs, slideDurationInSecs, 3)
                                    .Map(logLevelCountPair => string.Format("{0},{1}",
                                                          logLevelCountPair.Key, logLevelCountPair.Value));
      countByLogLevelAndTime.ForeachRDD(countByLogLevel =>
          foreach (var logCount in countByLogLevel.Collect())
      return ssc;

For more code samples, refer to Mobius\examples directory or Mobius\csharp\Samples directory.

API Documentation

Refer to Mobius C# API documentation for the list of Spark’s data processing operations supported in Mobius.

API Usage

Mobius API usage samples are available at:

  • Examples folder which contains standalone C# and F# projects that can be used as templates to start developing Mobius applications

  • Samples project which uses a comprehensive set of Mobius APIs to implement samples that are also used for functional validation of APIs

  • Mobius performance test scenarios implemented in C# and Scala for side by side comparison of Spark driver code


Refer to the docs folder for design overview and other info on Mobius

Build Status

Ubuntu 14.04.3 LTS Windows Unit test coverage
Build status Build status

Getting Started

Windows Linux
Build & run unit tests Build in Windows Build in Linux
Run samples (functional tests) in local mode Samples in Windows Samples in Linux
Run examples in local mode Examples in Windows Examples in Linux
Run Mobius app
Run Mobius Shell Not supported yet

Useful Links

Supported Spark Versions

Mobius is built and tested with Apache Spark 1.4.1, 1.5.2, 1.6.* and 2.0.


Mobius releases are available at References needed to build C# Spark driver applicaiton using Mobius are also available in NuGet

NuGet Badge

Refer to for the details on versioning policy and the contents of the release.



Mobius is licensed under the MIT license. See LICENSE file for full license information.


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Code of Conduct

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact [email protected] with any additional questions or comments.

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