Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?


trace() Function (Python, SLAX, and XSLT)


Python Syntax

SLAX Syntax

XSLT Syntax


Issue a trace message, which is sent to the trace file.

You must configure traceoptions under the respective script type in the configuration hierarchy in order to output a message to the trace file using the trace() function. The output goes to the configured trace file. If traceoptions is enabled, but no trace file is explicitly configured, the output goes to the default trace file for that script type.

The prefix associated with the namespace URI should be defined in the prefix-to-namespace mapping in the style sheet.



String that is output to the trace file.

Usage Examples

SLAX syntax:

XSLT syntax:

Python syntax:

Release Information

Function introduced in Junos OS Release 7.6.

Support for the slax namespace added in Junos OS Release 12.2.

Support for Python added in Junos OS Release 16.1R1 on QFX Series switches and ACX Series, MX Series, PTX Series, and T Series routers.

Support for Python added in Junos OS Release 17.1R1 on ACX500, ACX1000, ACX1100, ACX2000, ACX2100, ACX2200, and ACX4000 routers, and EX Series switches.

Support for Python added in Junos OS Release 17.3R1 on SRX1500, SRX4100, SRX4200, SRX5400, SRX5600, and SRX5800 devices and vSRX instances.

Support for Python added in Junos OS Release 18.3R1 on ACX5048 and ACX5096 routers.