Protocol Data Inputs v1.9.7


The Python code in this App is dual 2.7/3 compatible. This version of the App enforces Python 3 for execution of the modular input script when running on Splunk 8+ in order to satisfy Splunkbase AppInspect requirements. If running this App on Splunk versions prior to 8 , then Python 2.7 will get executed.


This is a Splunk Add-On for receiving data via a number of different data protocols.


But we already have TCP/UDP natively in Splunk

Yes we do. And by all means use those. But if you want to perform some custom data handling and pre-processing of the received data before it gets indexed (above and beyond what you can accomplish using Splunk conf files) , then this Modular Input presents another option for you.

Furthermore , this Modular Input also implements several other protocols for sending data to Splunk.


This Modular Input utilizes VERTX.IO version 2.1.4 under the hood.

This framework provides for an implementation that is :

Polyglot Custom Data Handling / Pre Processing

The way in which the Modular Input processes the received raw data is entirely pluggable with custom implementations should you wish.

This allows you to :

To do this you code a Vertx "Verticle" to handle the received data.

These data handlers can be written in numerous JVM languages.

You then place the handler in the $SPLUNK_HOME/etc/apps/protocol_ta/bin/datahandlers directory.

On the Splunk config screen for the Modular Input there is a field where you can then specify the name of this handler to be applied.

If you don't need a custom handler then the default handler com.splunk.modinput.protocolverticle.DefaultHandlerVerticle will be used.

To get started , you can refer to the default handler examples in the datahandlers directory.

Supported languages and file extensions

Note : experimental Nashorn support is included for js and coffee (requires Java 8). To use the Nashorn JS/Coffee engine rather than the default Rhino engine , then edit protocol_ta/bin/vertx_conf/


This is provisioned using your own Java Keystore that you can create using the keytool utility that is part of the JDK.

Refer to


Client certificate based authentication can be enabled for the TLS/SSL channels you setup.

VERTX Modules and Repositorys

Any required Vertx modules , such as various language modules for the polyglot functionality (JS , Scala , Groovy etc...) will be dynamically downloaded from online repositorys and installed in your protocol_ta/bin/vertx_modules directory.

You can edit your repository locations in protocol_ta/bin/vertx_conf/repos.txt

Performance tuning tips

Due to the nature of the async/event driven/non blocking architecture , the out of the box default settings may just well suffice for you.

But there are some other parameters that you can tune to take more advantage of your underlying computing resource(ie: cpu cores) available to you.

These are the server_verticle_instances and handler_verticle_instances params.

Refer to for an explanation of how increasing the number of instances may help you.

You can also tune the TCP accept queue settings (also requires OS tweaks) , particularly if you are receiving lots of connections within a short time span.

Refer to

Data Output

By default data will be output to STDOUT in Modular Input Stream XML format.

However you can bypass this if you wish and declare that data is output to a Splunk TCP port or via Splunk's HTTP Event Collector.


Binary File Declaration

This App contains a custom modular input written in Java

As such , the following binary JAR archives are required


Encryption of credentials

If you require an encrypted credential in your configuration , then you can enter it on the setup page.

Then in your configration stanza refer to it in the format {encrypted:somekey}

Where somekey is any value you choose to enter on the setup page to refer to your credential.

Activation Key

You require an activation key to use this App. Visit to obtain a non-expiring key


Modular Input logs will get written to $SPLUNK_HOME/var/log/splunk/protocolmodinput_app_modularinput.log

These logs are rotated after a max size of 5MB with a backup limit of 5.

Setup logs will get written to $SPLUNK_HOME/var/log/splunk/protocolmodinput_app_setuphandler.log

These logs are rotated daily with a backup limit of 5.

The Modular Input logging level can be specified in the input stanza you setup. The default level is INFO.

You can search for these log sources in the _internal index or browse to the Logs menu item on the App's navigation bar.

JVM Heap Size

The default heap maximum is 256MB. If you require a larger heap, then you can alter this in $SPLUNK_HOME/etc/apps/protocol_ta/bin/

JVM System Properties

You can declare custom JVM System Properties when setting up new input stanzas. Note : these JVM System Properties will apply to the entire JVM context and all stanzas you have setup


Support offer commercial support for implementing and any questions pertaining to this App.