Proposal: Get runtime logs from control API

[bdbai]

It would be good to provide an API for retrieving runtime logs for diagnostic purposes.

Feature breakdown

• retrieve most recent unformatted plaintext logs
• real-time updates

Potential implementation

For the API endpoint, WebSocket may be a good choice to transfer a large amount of data and real-time updates.
For the log collection, I can see two possible ways:

1. Prepare two fixed-sized buffers. Divert the logs to one of them, and swap when full. Every time a new connection comes in, we send back the buffers as a whole. Broadcast new logs to connected clients as well.
2. tail -f on the log file and send back the outputs. For console-based logs, assign temporary files as backing storage.

Any ideas or suggestions?

[eycorsican]

Why go through all these inconvenience when you can just tail on the log file? Reading a file is much easier than connecting to an API endpoint.

[bdbai]

1. The UI may not have access to the log file as the core do. WebUI is an example.
2. If the user chooses not to write logs to a file i.e. logoutput = console, there is no way for an external program to get the logs.