Frontend Logfile Access

[oetiker]

Issue

currently, the log file updates from all services are sent via a WebSocket to the frontend. this has recently caused serious performance issues as one service was spewing up to 300 log messages per second.

The log viewer in the frontend is implemented using the qooxdoo remote table model and as such is ideal for handling large amounts of data ... unfortunately, it is not used properly in the code.

Solution

In the backend, collect all the log messages created by the services and then provide two REST calls for the frontend to access them in 'reverse order'

• contLogLines (tells the fontend how many log lines there are)
• getLogLines (fetch the log data from line A to line B)

the websocket connection would only be used to alert the frontend of new loglines available ... using ratelimiting of a lot logging is happening

for bonus points, the frontend would allow to enter a filter wich gets sent along with backend requests to limit the the log lines shown.

Contributes to #502