Services

Example:

Drupal's event system allow to create triggers when an event has been happened like create a custom hook on drupal 7.

Use Event Subscriber service.

The EventSubscriber allow to execute an action on boot as hook_boot or hook_init of drupal 7.

Example.

You can call drupal 8 services statically as D7, but it is not the best practice (Like Here).
Example : $uuid = \Drupal::service('uuid')->generate();

Create a Service on Drupal 8

1.  Create a custom module (here : mytest)

2. Create the service Class
Example: src/MTService.php

Get All available services list

$services = \Drupal::getContainer()->getServiceIds();

Few use full services

//Generate a new UUID
$uuid = \Drupal::service('uuid')->generate();

 

Drupal 8 introduces the concept of services to decouple reusable functionality and makes these services pluggable and replaceable by registering them with a service container.