Magento 2 check product attribute already exsists

Question

I want to check if product attribute with same code already exists in setup file of my custom module?

How I could check it?

Answer 1

Try this:

Note: $eavSetupFactory should be an instance of  Magento\Eav\Setup\EavSetupFactory class, so add it to your constructor as a dependency.
/** @var Magento\Eav\Setup\EavSetup $eavSetup */
$eavSetup = $this->eavSetupFactory->create(['setup' => $setup]);

if(!$eavSetup->getAttributeId(\Magento\Catalog\Model\Product::ENTITY, 'attr_code')) {
    //Create the attribute
}

This will attempt to retrieve the attribute ID for the attribute with the code attr_code. If it returns a falsey value, the attribute does not exist.

Answer 2

// use Magento\Eav\Api\AttributeRepositoryInterface;

   /**
     * Installs data for a module
     *
     * @param ModuleDataSetupInterface $setup
     * @param ModuleContextInterface   $context
     * @return void
     */
    public function install(ModuleDataSetupInterface $setup, ModuleContextInterface $context)
    {
        if (version_compare($context->getVersion(), '1.0.0', '<')) {
            try {
                $this->attributeRepository->get(
                    Product::ENTITY,
                    self::SPECIAL_MEASURE_MESSAGE_ATTRIBUTE_CODE
                );
            } catch (NoSuchEntityException $e) {
                $this->eavSetup->addAttribute(
                    Product::ENTITY,
                    self::SPECIAL_MEASURE_MESSAGE_ATTRIBUTE_CODE,
                    [
                        'type'                    => 'varchar',
                        'input'                   => 'textarea',
                        'label'                   => 'Special Measure Message',
                        'required'                => false,
                        'group'                   => 'General',
                        'global'                  => ScopedAttributeInterface::SCOPE_GLOBAL,
                        'is_used_in_grid'         => true,
                        'user_defined'            => false,
                        'visible'                 => true,
                        'used_in_product_listing' => true,
                    ]
                );
            }
        }
    }

since \Magento\Framework\Setup\ModuleDataSetupInterface $setup does not contain a getAttributeId() method you always need to call the attributeRepository to get the attribute