rustler-core/lib/rustlers/README.md

rustler.rs

Contains the rustler! macro, which is used to define a Rustler.

Rustler is a trait that extends the RustlerAccessor trait.

Together, they define the interface and the common functionalities for all Rustlers.

The RustlerAccessor trait

The RustlerAccessor trait defines the interface for accessing the Rustler's data (getters and setters that all Rustlers must implement).

Some of the expected accessors are:

• status and set_status
• tickers and set_tickers
• msg_sender and set_msg_sender

The Rustler trait

The Rustler trait extends the RustlerAccessor trait and defines the interface for common Rustler's functionalities:

• start the Rustler, calling abstract connect if the Rustler is set to connect on start
• status change handling
• add new tickers to the Rustler (calling on_add at the end if tickers were added). Also calls connect if the Rustler is set to connect on add and the Rustler is not already connected
• delete tickers from the Rustler (calling on_delete at the end if tickers were deleted). Also calls disconnect if there are no more tickers in the Rustler.

The Rustler trait also defines the following abstract methods that must be implemented by each Rustler implementation.

• connect method that connects the Rustler to the data source
• disconnect method that disconnects the Rustler from the data source
• on_add method that is called when new tickers are added to the Rustler. This method is called when new tickers are added to the Rustler and must implement the logic to start tracking and rustling the new tickers.
• on_delete method that is called when tickers are deleted from the Rustler. This method is called when tickers are deleted from the Rustler and must implement the logic to stop tracking and rustling the deleted tickers.

The rustler! macro

The rustler! macro is used to define a Rustler and to automatically implement the RustlerAccessor trait. This adds the necessary fields and accessors to the struct.

Example:

rustler! {
    pub struct MyRustler { }
}

Now we have a MyRustler struct that implements the RustlerAccessor trait and has all the necessary fields and accessors :)

rustlerjar.rs

This files defines the RustlerJar struct.

A RustlerJar is a collection of Rustlers and their corresponding mappings to markets. Such mapping indicates which Rustler should be used for a given market.

It provides methods to retrieve Rustlers by Market.

The rustlerjar! macro

The rustlerjar! macro is used to create an instance of a RustlerJar on an easy way.

Example:

let rustler_jar = rustlerjar! {
  "NYSE", "NASDAQ" => MarketRustler::create,
  "BINANCE" => BinanceRustler::create(url),
};

let rustler = rustler_jar.get(&market);

the rustlerjar! expects a mapping of market names pointing to Rustler creation functions (constructors) and will return a RustlerJar instance.

Note: the rustlerjar! macro executes the create function for each Rustler, so in the example above, we assume that BinaceRustler::create(url) returns a function that creates a new instance of BinanceRustler and not an instance of BinanceRustler.

svc.rs

Contains the RustlersSvc struct.

The RustlersSvc struct is a service that manages the execution of several Rustlers from a RustlerJar.

It is responsible for starting and stopping the Rustlers on the right schedule.

It contains a MarketService, which connects to the database and is used to retrieve the markets (including their schedules) and their tickets. Then, for each market, it retrieves the corresponding Rustler from the RustlerJar, adds the tickers to the it, and starts it.

Note

Although it's not yet implemented, the RustlersSvc will also be responsible for adding and deleting tickers and rustlers at runtime.