It would be great to allow some kind of "manual" LLD discovery item, allowing to enter a JSON-formatted object in the WebUI.

This could have multiple use-cases :

• LLD debugging
• handling multiple instances of the same application :
  Let's say that you have several instances of an DB app running on the same host, and for each instance you'd like to monitor many items (in a template). AFAIK, for the moment, you have mainly two inelegant solutions :
  • create multiple hosts representing the app instances and link the template to each host
  • clone the template for each instance and edit it the avoid name conflicts
  • don't use a template and clone each item multiple times

With a "manual" LLD discovery, you would create a template, declare many item prototypes and link it to the host. Then, in the "manual" LLD discovery item, you would set following value in an editable field, for example :

{
  "data":[
  { "{#DBINSTANCENAME}":"Prod",  "{#DBINSTANCEPORT}":"30001" },
  { "{#DBINSTANCENAME}":"Dev",   "{#DBINSTANCEPORT}":"30002" },
  { "{#DBINSTANCENAME}":"Test",  "{#DBINSTANCEPORT}":"30003" }
  ]
}