AD0-E722 Sample Questions Answers

The issue here is that the database storage is not being fully cleaned after the test is run. The solution is to modify the method PHPDoc and change the annotation @magentoDbIsolation to enabled. This will ensure that the database storage is fully cleaned after the test is run. References: https://developer.adobe.com/commerce/testing/guide/integration/#database-isolation 1

The issue is being caused by the high coupling between objects (CBO) value of the class MyService. CBO is a metric that measures the number of classes that are coupled to a given class, either by method calls, property or parameter references, inheritance, or constants1. A high CBO value indicates that the class is too tightly coupled with other classes, which makes it more difficult to maintain, test, and reuse2. To reduce the CBO value, the Architect should introduce a new class that encapsulates the five scalar parameters that configure the behavior of MyService. This way, the constructor of MyService will only have one parameter of the new class type, instead of five scalar parameters. This will also make the code more readable and maintainable, as the new class can provide methods to access and manipulate the configuration data. The constants referencing other classes should not be consolidated into a string representation, as this would not reduce the CBO value and would make the code less clear and type-safe3. The number of different classes and interfaces referenced anywhere inside the class is not relevant for the CBO metric, as it only counts the classes that are coupled to the given class1. References: CBO coupling between object, Coupling Between Object classes (CBO), Cohesion and coupling of an object in OO programming

• Option C is correct because it configures the preload.keys correctly for Redis L2 caching on an Adobe Commerce on-premise instance. Redis L2 caching is a feature that allows storing the cache data in both Redis and the local file system. This way, the cache data can be loaded faster from the local storage, while Redis acts as a cache invalidation service. To use Redis L2 caching, the backend option for both frontend => page_cache and frontend => default must be set to Magento\Framework\Cache\Backend\RemoteSynchronizedCache1. To enable the preload feature, which reduces the number of requests to Redis, the preload.keys option must be specified with the cache keys that are loaded on each frontend request. However, unlike Redis L1 caching, the preload.keys must include the suffix :hash to indicate that only the hash values of the cache data are stored in Redis2. Therefore, the correct configuration for preload.keys is:

[ ‘762_EAV_ENTITY_TYPES:hash’, ‘762_GLOBAL_PLUGIN_LIST:hash’, ‘762_DB_IS_UP_TO_DATE:hash’, ‘762_SYSTEM_DEFAULT:hash’, ],

• Option A is incorrect because it configures the preload.keys incorrectly for Redis L2 caching. It uses the id_prefix of frontend => page_cache (063_) instead of frontend => default (762_) for the cache keys. This will cause a mismatch between the cache keys and the cache data, and result in incorrect or missing cache data. Moreover, it does not include the suffix :hash for the preload.keys, which is required for Redis L2 caching2.
• Option B is incorrect because it configures the preload.keys incorrectly for Redis L2 caching. It does not include the suffix :hash for the preload.keys, which is required for Redis L2 caching2. It also uses a wrong cache key (GLOBAL_PLUGIN_LIST) instead of GLOBAL_PLUGIN_LIST.
• Option D is incorrect because it configures the preload.keys incorrectly for Redis L2 caching. It uses a wrong id_prefix (162_) instead of frontend => default (762_) for the cache keys. This will cause a mismatch between the cache keys and the cache data, and result in incorrect or missing cache data. It also uses a wrong cache key (EAV_ENTITY_TYPES) instead of EAV_ENTITY_TYPES.

References:

• 1: Two-level caching | Adobe Commerce Developer Guide
• 2: Use Redis for default cache | Adobe Commerce Developer Guide

EAV attribute import uses the REPLACE statement, which deletes and inserts a new row with the same primary key value. This causes the auto-increment column to increase by one for each row, even if the row already exists. If the auto-increment column reaches its maximum value, which is 2147483647 for a signed INT, then any further REPLACE statement will fail with an integrity constraint violation error. References:

• EAV and extension attributes | Magento 2 Developer Documentation
• GitHub - techdivision/import-attribute: This library provides the functionality for the Magento 2 import of EAV attributes
• Data integrity in JSON (B) when replacing EAV - Stack Overflow

According to the Adobe Commerce documentation, to extend an existing GraphQL interface, the keyword extend must be used before the interface name. This indicates that the new declaration is adding or modifying fields to the existing interface, rather than redefining it. If the keyword extend is omitted, the new declaration will be ignored and the original interface will be used. In this case, the Architect wants to change the type of the my_attribute field in the ProductInterface interface, which is already declared in the Magento.CatalogGraphQl module. Therefore, the Architect should use the keyword extend before declaring the ProductInterface interface in the schema.graphqlsfile of the custom module. This will allow the Architect to override the type of the my_attribute field from Int to MyAttributeType.

References:

• Extend existing schema | Adobe Commerce Developer Guide
• Schema language with GraphQL | Adobe Commerce

According to the Adobe Commerce documentation, to create a new xml configuration file, the Architect needs to create a Data class and a Reader class for the custom module. The Data class is responsible for storing and retrieving the configuration data from the cache or the Reader class. The Data class should implement the “\Magento\Framework\Config\Data” interface or extend the “\Magento\Framework\Config\Data” class. The Reader class is responsible for reading and validating the xml configuration files from the file system. The Reader class should implement the '\Magento\Framework\Config\Reader\Filesystem" interface or extend the '\Magento\Framework\Config\Reader\Filesystem" class. The Architect also needs to declare the Data class and the Reader class in the di.xml file of the custom module, and specify the name of the xml configuration file, the converter class, and the schema locator class for the Reader class.

References:

• Configuration types | Adobe Commerce - Experience League
• Create configuration types | Adobe Commerce - Experience League

• Option C is correct because adjusting the ruleset.xml file with the new rule is the simplest and most effective way to implement the new code rule. The ruleset.xml file defines the coding standards that are applied by PHP_CodeSniffer. By extending the Magento 2 Coding Standard and adding a new rule, the Architect can customize the code analysis and enforce the company coding standards. The new rule can use the Magento2.Namespaces.ForbiddenNamespaces sniff to check for any usage of Helper classes in the code and report them as errors or warnings1.
• Option A is incorrect because creating a new composer package under the AwesomeAgency\CodingStandard\ namespace is not enough to implement the new code rule. The composer package is just a way to distribute and install the coding standard, but it does not define the rules themselves. The Architect still needs to create a ruleset.xml file and register it with PHP_CodeSniffer2.
• Option B is incorrect because creating a new class \AwesomeAgency\CodingStandard\Ruleset\ForbiddenNamespaces and specifying the rule inside the process method is unnecessary and complicated. The Architect does not need to create a new class or a new sniff for this rule, as there is already an existing sniff in the Magento 2 Coding Standard that can be used for this purpose. The Magento2.Namespaces.ForbiddenNamespaces sniff can be configured with an include-pattern element to specify which namespaces are forbidden1.

References:

• 1: Magento 2 Coding Standards | Adobe Commerce Developer Guide
• 2: How to create a custom coding standard | PHP_CodeSniffer Documentation

The magento-vars.php file is used to set the website or store view based on the HTTP host, but it does not affect GraphQL requests. GraphQL requests are handled by a separate controller that does not use the magento-vars.php file. Instead, GraphQL requests use the default store view of the default website, unless a store header or store cookie is provided in the request. The store header or cookie should contain the store code of the desired store view. For example, to query data from website_two, the request should include a header like store: store_two or a cookie like store=store_two12. References:

• GraphQL overview | Adobe Commerce 2.4 User Guide - Magento
• How to set up multiple websites with Magento 2 - Mageplaza

• Option A is correct because setting the consumers_wait_for_max_messages variable true in the deployment stage is the best way to meet the requirement. This variablecontrols whether the queue consumers should wait for a maximum number of messages to process before terminating. If this variable is set to true, the consumers will not terminate after processing the available messages in the queue, but will wait until they reach the max_messages limit or the cron job timeout. This way, the consumers can keep the TCP connections open and avoid delays in processing messages1.
• Option B is incorrect because increasing the multiple_process limit to spawn more processes for each consumer will not solve the issue of queue consumers closing TCP connections too often. The multiple_process limit determines how many parallel processes can be run for each consumer. Increasing this limit may improve the throughput of message processing, but it will also consume more server resources and may cause conflicts or errors. Moreover, it will not prevent the consumers from terminating after processing the available messages in the queue2.
• Option C is incorrect because changing the max_messages from 10,000 to 1,000 for CRON_CONSUMERS_RUNNER variable will worsen the issue of queue consumers closing TCP connections too often. The max_messages variable defines how many messages each consumer should process before terminating. Decreasing this variable will make the consumers terminate more frequently, which will result in more TCP connections being closed and reopened. This will increase the delays in processing messages3.

References:

• 1: Configure message queues | Adobe Commerce Developer Guide
• 2: Configure message queues | Adobe Commerce Developer Guide
• 3: Configure message queues | Adobe Commerce Developer Guide

The Architect should recommend replacing all Vendor\PaymentModule\Gateway\Config\Config Classes with virtualType of Magento\Payment\Gateway\Config\Config and setting under config.xml. This will avoid redundant dependency and duplicate code among the methods. The virtualType of Magento\Payment\Gateway\Config\Config will inherit the functionality of the base class and allow the customization of the constructor arguments, such as the pathPattern and valueHandlerPool. The backend_Model attribute of the user_secret field will specify that the value of this field should be encrypted and decrypted by the Magento\Config\Model\Config\Backend\Encrypted class, which implements the \Magento\Framework\App\Config\ValueInterface interface and uses the \Magento\Framework\Encryption\EncryptorInterfaceinternally12. This way, the payment modules do not need to depend on the \Magento\Framework\Encryption\EncryptorInterface or the \Magento\Framework\App\Config\ScopeConfigInterface directly, and can use the getValue method of the Magento\Payment\Gateway\Config\Config class to get the decrypted value of the user_secret field3. References:

• How to encrypt system configuration fields in Magento 2 - Mageplaza
• Magento 2: How to Encrypt/Decrypt System Configuration Fields - Webkul Blog
• Magento 2: How to create custom payment method - BelVG Blog

To display additional content on the home page based on a custom customer attribute, the Architect needs to do the following steps:

• Add a new context value of “my_attribute” to Magento\Framework\App\Http\Context. This will allow the Full Page Cache to generate different versions of the page for customers with different values of “my.attribute”. The context value can be set using a plugin on the Magento\Customer\Model\Context class.
• Add a dynamic block with the content to the Home Page. A dynamic block is a type of content block that can be configured to display only to specific customer segments or conditions. The Architect can use the ‘my.attribute’ in the conditions of the dynamic block and assign it to the Home Page in the Content > Blocks section of the Admin Panel. References:
• Private content | Magento 2 Developer Documentation
• Dynamic Blocks | Adobe Commerce 2.3 User Guide - Magento