Module solana_core::service

The service module implements a trait used by services and stages.

A Service is any object that implements its functionality on a separate thread. It implements a join() method, which can be used to wait for that thread to close.

The Service trait may also be used to implement a pipeline stage. Like a service, its functionality is also implemented by a thread, but unlike a service, a stage isn't a server that replies to client requests. Instead, a stage acts more like a pure function. It's a oneway street. It processes messages from its input channel and then sends the processed data to an output channel. Stages can be composed to form a linear chain called a pipeline.

The approach to creating a pipeline stage in Rust may be unique to Solana. We haven't seen the same technique used in other Rust projects and there may be better ways to do it. The Solana approach defines a stage as an object that communicates to its previous stage and the next stage using channels. By convention, each stage accepts a receiver for input and creates a second output channel. The second channel is used to pass data to the next stage, and so its sender is moved into the stage's thread and the receiver is returned from its constructor.

A well-written stage should create a thread and call a short run() method. The method should read input from its input channel, call a function from another module that processes it, and then send the output to the output channel. The functionality in the second module will likely not use threads or channels.

Traits

Service