HDFS File Writer Output Adapter Samples

About The Samples

The basic adapter sample illustrates the use of the TIBCO StreamBase® File Writer for Apache Hadoop Distributed File System (HDFS) by taking in a tuple and writing one of its fields contents to a file.

The advanced adapter sample illustrates reading from a sample input file multiple times and writing that data back out in various compression formats.

Initial Setup

You must open the sample application, FileWriterBasic.sbapp or FileWriterAdvanced.sbapp and select the Parameters tab and edit the value to represent your current HDFS setup and where you would like to store the sample data.

The file used in the FileWriterAdvanced.sbapp sample, SampleIn.txt needs to be placed on your HDFS file system in the location you specified in the Parameters tab before this sample will be able to run.

Running The Basic Sample in StreamBase Studio

In the Package Explorer, double-click to open the FileWriterBasic.sbapp application. Make sure the application is the currently active tab in the EventFlow Editor.
Click the Run button. This opens the SB Test/Debug perspective and starts the application.
In the Manual Output view, switch the Stream to Data, then enter a string value such as 'test', and then click Send Data to send a data tuple to be written to the file. Repeat for as many lines as you wish.
In the Application Output view, observe tuples emitted on the Status output streams indicating actions performed to the file.
In the Manual Output view, switch the Stream to Control, then enter 'Close' into the Command field, and then click Send Data to send a control tuple which will close the current file for writing.
Press F9 or click the Stop Running Application button.
This demo will have now created a file in your project called SampleOut.txt containing the lines of data you submitted.

Running The Advanced Sample in StreamBase Studio

In the Package Explorer, double-click to open the FileWriterAdvanced.sbapp application. Make sure the application is the currently active tab in the EventFlow Editor.
Click the Run button. This opens the SB Test/Debug perspective and starts the application.
In the Application Output view, observe tuples emitted on the Status output streams indicating actions performed to the files.
Press F9 or click the Stop Running Application button.
This demo will have now created multiple files in your project:
1. Sample.gz - This file is a GZip compressed file created from the SampleIn.txt file.
2. Sample.gz2 - This file is a BZip2 compressed file created from the SampleIn.txt file.
3. Sample.zip - This file is a Zip compressed file created from the SampleIn.txt file.
4. SampleOut.txt - This file is a un-compressed file created from the SampleIn.txt file.

Importing This Sample into StreamBase Studio

In StreamBase Studio, import this sample with the following steps:

From the top menu, select File → Load StreamBase Sample.
Select File Writer output adapter from the StreamBase Standard Adapters category.
Click OK.

StreamBase Studio creates a single project containing the sample files.

Sample Location

When you load the sample into StreamBase Studio, Studio copies the sample project's files to your Studio workspace, which is normally part of your home directory, with full access rights.

Important

Load this sample in StreamBase Studio, and thereafter use the Studio workspace copy of the sample to run and test it, even when running from the command prompt.

Using the workspace copy of the sample avoids the permission problems that can occur when trying to work with the initially installed location of the sample. The default workspace location for this sample is:

studio-workspace/sample_adapter_embedded_hdfsfilewriter

See Default Installation Directories for the location of studio-workspace on your system.

In the default TIBCO StreamBase installation, this sample's files are initially installed in:

streambase-install-dir/sample/adapter/embedded/hdfsfilewriter

See Default Installation Directories for the location of streambase-install-dir on your system. This location may require administrator privileges for write access, depending on your platform.