How to use update-policy type "external"

[Vladimir Brik]

Hello

I am trying to set up an "external" dynamic DNS update 
policy but I can't figure out the syntax.

The documentation [1] says that the "identity" field needs 
to be in the form local:PATH, but using something like the 
following results in an error: "expected unquoted string 
near '/'", and I don't know how to fix it.

update-policy {
     grant local:/tmp/sock external NAME txt;
};

Also, the documentation doesn't say how NAME is interpreted. 
Is it ignored?


Thanks very much

Vlad


[1] 
https://bind9.readthedocs.io/en/latest/reference.html#namedconf-statement-update-policy