Client Pool Architecture

Motivations

In situations where multiple connections are expected, and the number of connections can vary greatly, the Client Pool reduces time spent waiting for the creation of a Mixnet Client blocking your code sending traffic through the Mixnet. Instead, a configurable number of Clients can be generated and run in the background which can be very quickly grabbed, used, and disconnected.

The Pool can be simply run as a background process for the runtime of your program.

Clients & Lifetimes

The Client Pool creates ephemeral Mixnet Clients which are used and then disconnected. Using the TcpProxy as an example, Clients are used for the lifetime of a single incoming TCP connection; after the TCP connection is closed, the Mixnet client is disconnected.

Clients are popped from the pool when in use, and another Client is created to take its place. If connections are coming in faster than Clients are replenished, you can instead generate an ephemeral Client on the fly, or wait; this is up to the developer to decide. You can see an example of this logic in the example on the next page.

Runtime Loop

Aside from a few helper / getter functions and a graceful disconnect_pool(), the Client Pool is mostly made up of a very simple loop around some conditional logic making up start():

• if the number of Clients in the pool is < client_pool_reserve_number (set on new()) then create more,
• if the number of Clients in the pool == client_pool_reserve_number (set on new()) then sleep,
• if client_pool_reserve_number == 0 just sleep.

disconnect_pool() will cause this loop to break via cancellation token.