F# – Starting an Agent with supervision

In Erlang, we have the Supervisor behaviour which makes it very easy to provide the means to monitor and restart a whole network of workers and other supervisors based on some configured strategy.

The MailboxProcessor (aka agents) in F# doesn’t come with the same higher-level abstractions (such as Erlang’s gen_server, gen_fsm behaviours) by default, but it’s very easy to mimic some of their capabilities by building on top of the standard F# agents.

Luca Bolognese’s lightweight LAgent framework is a perfect example and even provides interesting possibilities such as hot swapping of code (although still some way off of what’s possible in Erlang in this regard).

Similarly, the following snippet shows how you can start an agent with supervision so that any escaped exceptions (which will crash the agent) are trapped and restarts the agent: