Server-Sent-Events

[dtq-two]

Problem

Currently the frontend fetches all groups, nodes, devices and messages in a fixed interval. This results in unnecessary requests when nothing is changing and a lag when a lot is changing. Server-Sent-Events seem like a fitting solution to this problem

Idea

• Send an Event whenever a new message was handled that contains the new necessary informations:

NBIRTH

• The new node object
• The new node metrics
• node devices are not necessary, because they are not changing

NDEATH

• The new node object
• node devices and node metrics are not necessary, because they are not changing except from becoming offline/stale

NDATA

• The new node object
• The new node metrics

DBIRTH

• The new node object (because of seq number)
• The new device object
• The new device metrics

DDEATH

• The new node object (because of seq number)
• device and device metrics are not necessary, because they are only becoming offline/stale

DDATA

• The new node object (because of seq number)
• The new device metrics

Open issues

Currently, we utilize Tabulator with React-Tabulator to update views in the browser once SSE are received. However, due to some changes it does not seem to be possible anymore to use React functional components. A work-around seems to be to use React class components instead.