Erlang server connection pool

Question

I have a service that is in Erlang. I am trying to connect to the service. However sometimes the connection creation gets timed out. I believe this might be because the service might be busy. This is periodic, on re-executing my program some time later it works well.

I am not sure how connection pool is defined in Erlang. I am trying to look into the same (unfortunately not much success so far) and would like to change the connection pool size. I am mainly looking into how connection management in done when executing jsonrpc commands. As per documentation only a new connection is created between client and server from any communication. I am trying to identify how to change upper limit for this if any.

Thank-you

Answer 1

I am not sure how connection pool is defined in Erlang.

There are some well-known connection pools in Erlang like ranch and swarm , which here you can find a summary of them.

I am trying to identify how to change upper limit for this if any.

For example in case of ranch you can set the connection pool size this way:

AcceptorNumbers = 100,
{ok, _} = ranch:start_listener(
    ListenerRef, 
    AcceptorNumbers,
    Transport, [{port, Port}],
    Protocol, Options
).

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Also you can create your own connection pool on top of OTP behaviours. For example, a pool of Generic Finite State Machines ( gen_fsm ) which holds client connections and are supervised can be as simple as this tutorial .