dovecot - Mar 2018 - Is possible to override Dovecot variables or Sieve env vars and extdata lookups

Are the dovecot environment variables mutable? I'd like to override 
like:

set "${env.vnd.dovecot.username}" "someuser at example.org"

Or better, I prefer to override %u Dovecot variable during the userdb 
lookup.

Is either possible?

PS, when Sieve does extdata lookups for username key, where does 
username come from? %u?  Does an override as above change the dict 
lookup key for extdata?

On 19.03.2018 06:40, MRob wrote:
> Are the dovecot environment variables mutable? I'd like to override
like:
>
> set "${env.vnd.dovecot.username}" "someuser at
example.org"
>
> Or better, I prefer to override %u Dovecot variable during the userdb
> lookup.
>
> Is either possible?
>
> PS, when Sieve does extdata lookups for username key, where does
> username come from? %u?? Does an override as above change the dict
> lookup key for extdata?
You could override the %u variable, but overriding it in userdb will
have surprising consequences. Basically this amounts to same as changing
username for the user. So don't. Please set some other thing like,
my_special_var=something in userdb, then you should be able to access it
as env.vnd.dovecot.my_special_var

Aki

On 2018-03-19 06:31, Aki Tuomi wrote:
> On 19.03.2018 06:40, MRob wrote:
>> Are the dovecot environment variables mutable? I'd like to override
>> like:
>> 
>> set "${env.vnd.dovecot.username}" "someuser at
example.org"
>> 
>> Or better, I prefer to override %u Dovecot variable during the userdb
>> lookup.
>> 
>> Is either possible?
>> 
>> PS, when Sieve does extdata lookups for username key, where does
>> username come from? %u?? Does an override as above change the dict
>> lookup key for extdata?
> 
> You could override the %u variable, but overriding it in userdb will
> have surprising consequences. Basically this amounts to same as 
> changing
> username for the user.
This is useful to work with a older system in my case, username should 
seem as a new one anyways. I accept the consequence. :)

I tried return only "u" in the passdb and usedb lookup (also
"userdb_u")
but it did not work. Where can I override %u? Can I do it in both passdb 
and userdb lookup?