Q:

Is there a Nifi Processor to query Active Directory? 

I'm trying to get a containerised Nifi instance to use Active Directory as a flowfile source. 
I want to periodically run a query against AD (e.g. LDAP query), and return a list of specific users to Nifi in order to create a folder on disk for each user. 
I've looked through the list of processors and haven't spotted anything which seems suitable for querying AD.   Am I missing something obvious? 
What is the best way to achieve this? 

A:

I was stuck in a vanilla Nifi container and the container didn't have ldapsearch available so the ExecuteProcess Processor wouldn't work out of the box. 
The container also didn't have the correct Python libraries for ldap, so ExecuteScript wouldn't work OOTB either. 
I could have build a new container based off the official and installed ldapsearch, or I could have mounted the python libs in the container but didn't end up going down either route. 
I solved this by getting a colleague to write a Nifi processor (NAR file) for querying LDAP.  It took him about half an hour to research nifi and write a processor that took a few parameters:

LDAP Server string (e.g. ldaps://servername.com:636)
LDAP Bind DN (user with perms to query ldap)
LDAP Bind Password
LDAP Search Base
LDAP Group DN (Group to search for)
Nifi Attribute (Varible to store results in)

The processor (based off a simple ldap query "ldapquery (&(objectCategory=user)(memberOf=<ldap group DN))")  returns a flow file for each user in the group, containing the user object details we're interested in. 
To get this to work we just had to mount the single custom processor .nar file into the Nifi lib folder, and update the container's Java keystore file to accept our custom certificates (to enable SSL). 
It seemed like the most elegant solution, and means the administrators maintaining the system don't need to worry about understanding custom scripts - effectively lowering the maintenance overhead.