Replace custom event loop with open-source alternative

[abeltrano]

Is your feature request related to a problem? Please describe.
The code to manage the event loop was written from scratch. During early development, there were not many event loop features that were needed, so a hand-written one allowed rapid prototyping. However, the event loop has become more complicated and so, it may be a better idea to replace the hand-written event loop code with a publicly available, well documented and tested event library.

Describe the solution you'd like
The hand-written event code should be replaced with a well-tested, open-source event library for C. Many popular event libraries available, the following libraries are a good start for consideration:

• libevent
• libev
• libuv

Describe alternatives you've considered

• Leave the event loop as it is. This risks more complicated maintenance and requires more bootstrap time for onboarding.

Additional context

• None

[forwardpointer]

I'll look into using libevent for this. It seems the most promising out of the three listed.

[forwardpointer]

Would sd-event be a viable option since we are already using libsystemd? It provides an event loop for events based on file IO, signals, and timers.

[abeltrano]

Would sd-event be a viable option since we are already using libsystemd? It provides an event loop for events based on file IO, signals, and timers.

Yes, sd-event looks like a great candidate and I can't see a reason why we would prefer the other alternatives over it, given our goals. If we needed to support non-Linux scenarios, it would be a different story, but this project is Linux specific, so not an issue here.

Looking at the sd-event implementation, it's very close to our own event loop so switching to it shouldn't change behavior much, if at all.