Build E-Commerce Apps with Reactive Programming in Spring Boot/

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Logging Reactor Flows

Logging Reactor Flows

Get introduced to logging Reactor flows.

We'll cover the following...

Debugging after the fact isn’t our only tool in Reactor. It’s possible to log actions as they happen.

Getting data reactively

When we sit down to insert some log.debug() statements into our Reactor code we might find that it’s suddenly not so easy.

This isn’t precisely the fault of Reactive Streams’ asynchronous nature, but instead Project Reactor’s application of functional programming techniques. By using lambda functions and method references, we just don’t have as many places to insert those convenient log.debug() statements.

For example, Java 8 programming lets us write code like this:

Mono<Double> findPriceByMethodReference(String id) {
    // tag::method-handle[]
    return itemRepository.findById(id)
        .map(Item::getPrice);
    // end::method-handle[]
}
Reactively getting data and using a Java 8 method reference transform

Reactor’s .map() operator transforms the retrieved Item into a price using Item::getPrice.

With the wide adoption of Java 8, it’s not uncommon to find code like this all over ...