Where to find shipment event in Magento2

Question

I am trying to build a custom module that will trigger off a text message when Magento receives shipping information on orders.

I know I can trigger off email, sms etc when an order is placed by listening for the event 'order' referring to this line

$this->_eventManager->dispatch('sales_order_place_after', ['order' => $this]);

In this php file

Magento/Sales/Model/Order.php 

So my question is where can I find the event that triggers the default email that gets send when a shipment is generated in Magento2?

Answer 1

sales_order_shipment_save_after

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Event/etc/events.xsd">
    <event name="sales_order_shipment_save_after">
        <observer name="myname" instance="Vendor\MyModule\Observer\ProcessShipment" />
    </event>
</config>

then use it like this

<?php
namespace Vendor\MyModule\Observer;

use Magento\Framework\Event\ObserverInterface;

class ProcessShipment implements ObserverInterface
{
    /**
     *
     * @param \Magento\Framework\Event\Observer $observer
     * @return $this
     */
    public function execute(\Magento\Framework\Event\Observer $observer)
    {
        $shipment = $observer->getEvent()->getShipment();
        $order = $shipment->getOrder();
        // your code here
    }
}

Answer 2

Open vendor/magento/module-shipping/Controller/Adminhtml/Order/Shipment/Save.php and check the following line:

if (!empty($data['send_email']) && $this->salesData->canSendNewShipmentEmail()) {
    $this->shipmentSender->send($shipment);
}

Following class is responsible: vendor/magento/module-sales/Model/Order/Email/Sender/ShipmentSender.php