how i can override the observer of other modules in magento 2

Question

how i can override observer of other module(custom module)

to my another custom modules in magento 2

is it possible ???

Does anyone have an idea?

ex :

custom module 1:

the observer for catalog price change

custom module 2:

i want the price of changed by observer in custom module1.

Answer 1

Yes, you can using preference

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <preference for="Vendor1\ModuelName1\Observer\FileName1" type="Vendor2\ModuelName2\Observer\FileName2" />
</config>

Just copy the existing observer from FileName1.php to FileName2.php and do alter the namespace and all. and I hope it works.

Despite executing first observer it will execute second observer.

Answer 2

Using Preference it's is possible

etc/di.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <preference for="\Vendor\module1\file\location" type="\Vendor\module2\file\location" /> 
</config>

Answer 3

To override an observer, I think better way is to use events.xml rather than using preference.

Suppose you have events.xml in ModuleA

<?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="some_event">
        <observer name="myObserverName" instance="MyCompany\ModuleA\Observer\MyObserver" />
    </event>
</config>

Now if you want to override the observer MyCompany\ModuleA\Observer\MyObserver, then create events.xml in your custom module as follows

<?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="some_event">
            <observer name="myObserverName" instance="MyCompany\CustomModule\Observer\MyObserver" />
        </event>
    </config>

And in your custom module's(MyCompany_CustomModule) module.xml add sequence of MyCompany_ModuleA

<?xml version="1.0" encoding="UTF-8" ?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
    <module name="MyCompany_CustomModule">
        <sequence>
            <module name="MyCompany_ModuleA" />
        </sequence>
    </module>
</config> 

Also, Magento recommends to use plugins for data modification. Observers should not be used for data modifications.