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Reading and writing data in MongoDB using a Spark Streaming Job

This scenario applies only to Talend Real Time Big Data Platform and Talend Data Fabric.

For more technologies supported by Talend, see Talend components.

In this scenario, you create a Spark Streaming Job to extract data about given movie directors from MongoDB, use this data to filter and complete movie information and then write the result into a MongoDB collection.

The sample data about movie directors reads as follows:
1;Gregg Araki	
2;P.J. Hogan 
3;Alan Rudolph 
4;Alex Proyas
5;Alex Sichel

This data contains the names of these directors and the ID numbers distributed to them.

The structure of this data in MongoDB reads as follows:
{ "_id" : ObjectId("575546da3b1c7e22bc7b2189"), "person" : { "id" : 3, "name" : "Alan Rudolph" } }
{ "_id" : ObjectId("575546da3b1c7e22bc7b218b"), "person" : { "id" : 4, "name" : "Alex Proyas" } }
{ "_id" : ObjectId("575546da3b1c7e22bc7b218c"), "person" : { "id" : 5, "name" : "Alex Sichel" } }
{ "_id" : ObjectId("575546da3b1c7e22bc7b2188"), "person" : { "id" : 1, "name" : "Gregg Arakit" } }
{ "_id" : ObjectId("575546da3b1c7e22bc7b218a"), "person" : { "id" : 2, "name" : "P.J. Hogan" } }

Note that the sample data is created for demonstration purposes only.

tHDFSConfiguration is used in this scenario by Spark to connect to the HDFS system where the jar files dependent on the Job are transferred.

In the Spark Configuration tab in the Run view, define the connection to a given Spark cluster for the whole Job. In addition, since the Job expects its dependent jar files for execution, you must specify the directory in the file system to which these jar files are transferred so that Spark can access these files:
  • Yarn mode (Yarn client or Yarn cluster):

    • When using Google Dataproc, specify a bucket in the Google Storage staging bucket field in the Spark configuration tab.

    • When using HDInsight, specify the blob to be used for Job deployment in the Windows Azure Storage configuration area in the Spark configuration tab.

    • When using Altus, specify the S3 bucket or the Azure Data Lake Storage for Job deployment in the Spark configuration tab.
    • When using Qubole, add a tS3Configuration to your Job to write your actual business data in the S3 system with Qubole. Without tS3Configuration, this business data is written in the Qubole HDFS system and destroyed once you shut down your cluster.

    • When using on-premises distributions, use the configuration component corresponding to the file system your cluster is using. Typically, this system is HDFS and so use tHDFSConfiguration.

  • Standalone mode: use the configuration component corresponding to the file system your cluster is using, such as tHDFSConfiguration Apache Spark Batch or tS3Configuration Apache Spark Batch.

    If you are using Databricks without any configuration component present in your Job, your business data is written directly in DBFS (Databricks Filesystem).

Prerequisites:

  • The Spark cluster and the MongoDB database to be used have been properly installed and are running.

  • The above-mentioned data has been loaded in the MongoDB collection to be used.

To replicate this scenario, proceed as follows:

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