I am beginning to expand an application to 2 instances of Node-RED. This is to separate defined core functions which we do not want to expose to technicians, and the individual installation particulars of integration to sensors and devices.
The initial instance is installed globally. There will be programming for the sensors which needs to pass messages to the core functions. Then the result of the core functions will output information to output devices like printers. Devices need to be maintained, replaced and customized per the install.
Question: What is the recommended best practice to efficiently message between Node-RED "Device Instance 1" hosting input devices to the "Core Instance 2" and then back to the Outputs on "Device instance1"?
HTTP?
Web Socket?
TCP?
MQTT?
Thanks.