Tango: Use tags for selecting devices from .xml file

The file /online_dir/online.xml or an alternative .xml file contains the Tango devices that are used by an online session. The device selection can be further specialized with the help of tags. They appear on the command line and in the .xml file, e.g.:

online -tki -tags user
online -tki -tags eh1,oh1

Note that there is no blank space in the string “eh1,oh1”.

Here is a device definition in an .xml file:

<device>
 <name>exp_vfc01</name>
 <tags>expert,eh1</tags>
 <type>adc</type>
 <module>vfcadc</module>
 <device>p09/vfc/exp.01</device>
 <control>tango</control>
 <hostname>haso107tk:10000</hostname>
</device>

The file /online_dir/exp_ini.exp may contain code that is executed depending on the tag specification:

if find( trnlnm( online_xml_tags), expert)
  say " we are experts"
  wait
endif

A device is selected for an Online session, if one of the following conditions applies:

there is no '-tags ...' parameter on the command line
at least on element of the <tags> section of the device matches at least one '-tags' element of the command line.

The implementation of the tags feature may change, if use cases show up that are not covered by the current implementation. However the typical applications are described in the following subsections.

Subsections