pv: add $def pseudo variable

[lazedo]

Pre-Submission Checklist

• Commit message has the format required by CONTRIBUTING guide
• Commits are split per component (core, individual modules, libs, utils, ...)
• Each component has a single commit (if not, squash them into one commit)
• No commits to README files for modules (changes must be done to docbook files
  in doc/ subfolder, the README file is autogenerated)

Type Of Change

• Small bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds new functionality)
• Breaking change (fix or feature that would change existing functionality)

Checklist:

• PR should be backported to stable branches
• Tested changes locally
• Related to issue #XXXX (replace XXXX with an open issue number)

Description

allows the use definitions as pseudo-variables

#!trydef XIP "$HN(i)"
#!substdef "!MY_IP_ADDRESS!$def(XIP)!g"

#!substdef "!MY_HOSTNAME!$HN(f)!g"
#!trydef REGISTRAR_MIN_EXPIRES 300

loadmodule "registrar.so"
modparam("registrar", "min_expires", REGISTRAR_MIN_EXPIRES)

route[SOMETHING]
{
xlog("L_INFO", "configured value of registrar min-expires is $def(REGISTRAR_MIN_EXPIRES)\n");
xlog("L_INFO", "configured value of host is MY_HOSTNAME\n");
xlog("L_INFO", "configured value of ip is MY_IP_ADDRESS\n");
}

[miconda]

Thanks!

[oej]

Cool. Thanks!