Splunk® Enterprise

Getting Data In

Download manual as PDF

Splunk version 4.x reached its End of Life on October 1, 2013. Please see the migration information.
This documentation does not apply to the most recent version of Splunk. Click here for the latest version.
Download topic as PDF

Assign default fields dynamically

This feature allows you to dynamically assign default fields, also known as "metadata", to files as they are being consumed by Splunk. Use this feature to specify source type, host, or source dynamically for incoming data. This feature is useful mainly with scripted data -- either a scripted input or an existing file processed by a script.

Important: Splunk does not recommend using dynamic metadata assignment with ongoing file monitoring (tail) inputs. For more information about file inputs, refer to Monitor files and directories in this manual.

To use this feature, you append a single dynamic input header to your file and specify the metadata fields you want to assign values to. The available metadata fields are sourcetype, host, and source.

You can use this method to assign metadata instead of editing inputs.conf, props.conf, and transforms.conf.

Configure a single input file

To use this feature for an existing input file, edit the file (either manually or with a script) to add a single input header:

      ***SPLUNK*** <metadata field>=<string> <metadata field>=<string> ...
  • Set <metadata field>=<string> to a valid metadata/value pair. You can specify multiple pairs. For example, sourcetype=log4j host=swan.
  • Add the single header anywhere in your file. Any data following the header will be appended with the attributes and values you assign until the end of the file is reached.
  • Add your file to $SPLUNK_HOME/var/spool/splunk or any other directory being monitored by Splunk.

Configure with a script

In the more common scenario, you write a script to dynamically add an input header to your incoming data stream. Your script can also set the header dynamically based on the contents of the input file.

About default fields (host, source, sourcetype, and more)
Create custom fields at index-time

This documentation applies to the following versions of Splunk® Enterprise: 4.3, 4.3.1, 4.3.2, 4.3.3, 4.3.4, 4.3.5, 4.3.6, 4.3.7, 5.0, 5.0.1, 5.0.2, 5.0.3, 5.0.4, 5.0.5, 5.0.6, 5.0.7, 5.0.8, 5.0.9, 5.0.10, 5.0.11, 5.0.12, 5.0.13, 5.0.14, 5.0.15, 5.0.16, 5.0.17, 5.0.18


I am only able to set certain metadata fields using this technique. For example, "host" and "source" can be changed. But I cannot alter "foo" or "_time", for example.

June 4, 2012

In the syntax "=":<br />If contains embedded spaces, = sign or other weird characters, is there an easy way to escape?

May 19, 2011

Was this documentation topic helpful?

Enter your email address, and someone from the documentation team will respond to you:

Please provide your comments here. Ask a question or make a suggestion.

You must be logged into splunk.com in order to post comments. Log in now.

Please try to keep this discussion focused on the content covered in this documentation topic. If you have a more general question about Splunk functionality or are experiencing a difficulty with Splunk, consider posting a question to Splunkbase Answers.

0 out of 1000 Characters