To debug XPath expressions, you can enable XPath tracing in confd.conf using the following:
/confdConfig/logs/xpathTraceLog - container element
xpathTraceLog is a log for understanding and troubleshooting XPath evaluations. When this log is enabled, the execution of all XPath queries evaluated by ConfD is logged to a file.
This will slow down ConfD, so be careful when enabling this log. This log is not rotated, i.e. use logrotate(8).
/confdConfig/logs/xpathTraceLog/enabled (xs:boolean) [false] enabled is either "true" or "false". If "true", all XPath execution is logged.
/confdConfig/logs/xpathTraceLog/filename (xs:string) The name of the file where the XPath trace log is written.
An example setting in confd.conf for this section is as follows:
<xpathTraceLog>
<enabled>true</enabled>
<filename>./xpath.trace.log</filename>
</xpathTraceLog>
Another mechanism is to use the ‘must’ and ‘xpath’ CLI commands as shown in the examples.confd/validate/xpath_must example.