Magento 2 Customer Attribute - Simple Text Field

ExternalId.php

<?php declare(strict_types=1);

namespace Manick\Customer\Setup\Patch\Data;

use Exception;
use Psr\Log\LoggerInterface;
use Magento\Customer\Api\CustomerMetadataInterface;
use Magento\Customer\Model\Customer;
use Magento\Customer\Model\ResourceModel\Attribute as AttributeResource;
use Magento\Customer\Setup\CustomerSetup;
use Magento\Customer\Setup\CustomerSetupFactory;
use Magento\Framework\Setup\ModuleDataSetupInterface;
use Magento\Framework\Setup\Patch\DataPatchInterface;

/**
 * Creates a customer attribute for managing a customer's external system ID
 */
class ExternalId implements DataPatchInterface
{
    /**
     * Attribute constants
     */
    const ATTRIBUTE_CODE = 'manick_external_id';
    const ATTRIBUTE_LABEL = 'External ID';

    /**
     * @var ModuleDataSetupInterface
     */
    private ModuleDataSetupInterface $moduleDataSetup;

    /**
     * @var CustomerSetup
     */
    private CustomerSetup $customerSetup;

    /**
     * @var AttributeResource
     */
    private AttributeResource $attributeResource;

    /**
     * @var LoggerInterface
     */
    private LoggerInterface $logger;

    /**
     * Constructor
     *
     * @param ModuleDataSetupInterface $moduleDataSetup
     * @param CustomerSetupFactory $customerSetupFactory
     * @param AttributeResource $attributeResource
     * @param LoggerInterface $logger
     */
    public function __construct(
        ModuleDataSetupInterface $moduleDataSetup,
        CustomerSetupFactory $customerSetupFactory,
        AttributeResource $attributeResource,
        LoggerInterface $logger
    ) {
        $this->moduleDataSetup = $moduleDataSetup;
        $this->customerSetup = $customerSetupFactory->create(['setup' => $moduleDataSetup]);
        $this->attributeResource = $attributeResource;
        $this->logger = $logger;
    }

    /**
     * Get array of patches that have to be executed prior to this.
     *
     * Example of implementation:
     *
     * [
     *      \Vendor_Name\Module_Name\Setup\Patch\Patch1::class,
     *      \Vendor_Name\Module_Name\Setup\Patch\Patch2::class
     * ]
     *
     * @return string[]
     */
    public static function getDependencies(): array
    {
        return [];
    }

    /**
     * Get aliases (previous names) for the patch.
     *
     * @return string[]
     */
    public function getAliases(): array
    {
        return [];
    }

    /**
     * Run code inside patch
     */
    public function apply()
    {
        // Start setup
        $this->moduleDataSetup->getConnection()->startSetup();

        try {
            // Add customer attribute with settings
            $this->customerSetup->addAttribute(
                CustomerMetadataInterface::ENTITY_TYPE_CUSTOMER,
                self::ATTRIBUTE_CODE,
                [
                    'label' => self::ATTRIBUTE_LABEL,
                    'required' => 0,
                    'position' => 100,
                    'system' => 0,
                    'user_defined' => 1,
                    'is_used_in_grid' => 1,
                    'is_visible_in_grid' => 1,
                    'is_filterable_in_grid' => 1,
                    'is_searchable_in_grid' => 1,
                ]
            );

            // Add attribute to default attribute set and group
            $this->customerSetup->addAttributeToSet(
                CustomerMetadataInterface::ENTITY_TYPE_CUSTOMER,
                CustomerMetadataInterface::ATTRIBUTE_SET_ID_CUSTOMER,
                null,
                self::ATTRIBUTE_CODE
            );

            // Get the newly created attribute's model
            $attribute = $this->customerSetup->getEavConfig()
                ->getAttribute(Customer::ENTITY, self::ATTRIBUTE_CODE);

            // Make attribute visible in Admin customer form
            $attribute->setData('used_in_forms', [
                'adminhtml_customer'
            ]);

            // Save attribute using its resource model
            $this->attributeResource->save($attribute);
        } catch (Exception $e) {
            $this->logger->err($e->getMessage());
        }

        // End setup
        $this->moduleDataSetup->getConnection()->endSetup();
    }
}