"Area code is not set" in var/log

Question

I have this kind of error in logs that I have difficulties to understand. I found some infos on "Area code is not set" errors in CLI, but not on the frontend side. Have you suggestions ?

{"0":"Area code is not set","1":"#0 /data/www/.../.../vendor/magento/module-customer/Model/Plugin/CustomerNotification.php(78): Magento\Framework\App\State->getAreaCode()\n#1 /data/www/.../.../vendor/magento/framework/Interception/Interceptor.php(121): Magento\Customer\Model\Plugin\CustomerNotification->beforeDispatch(Object(Magento\Customer\Controller\Section\Load\Interceptor), Object(Magento\Framework\App\Request\Http))\n#2 /data/www/.../.../vendor/magento/framework/Interception/Interceptor.php(153): Magento\Customer\Controller\Section\Load\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))\n#3 /data/www/.../.../generated/code/Magento/Customer/Controller/Section/Load/Interceptor.php(26): Magento\Customer\Controller\Section\Load\Interceptor->___callPlugins('dispatch', Array, Array)\n#4 /data/www/.../.../vendor/magento/framework/App/FrontController.php(55): Magento\Customer\Controller\Section\Load\Interceptor->dispatch(Object(Magento\Framework\App\Request\Http))\n#5 /data/www/.../.../vendor/magento/framework/Interception/Interceptor.php(58): Magento\Framework\App\FrontController->dispatch(Object(Magento\Framework\App\Request\Http))\n#6 /data/www/.../.../vendor/magento/framework/Interception/Interceptor.php(138): Magento\Framework\App\FrontController\Interceptor->___callParent('dispatch', Array)\n#7 /data/www/.../.../vendor/magento/module-store/App/FrontController/Plugin/RequestPreprocessor.php(94): Magento\Framework\App\FrontController\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))\n#8 /data/www/.../.../vendor/magento/framework/Interception/Interceptor.php(135): Magento\Store\App\FrontController\Plugin\RequestPreprocessor->aroundDispatch(Object(Magento\Framework\App\FrontController\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))\n#9 /data/www/.../.../vendor/magento/module-page-cache/Model/App/FrontController/BuiltinPlugin.php(73): Magento\Framework\App\FrontController\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))\n#10 /data/www/.../.../vendor/magento/framework/Interception/Interceptor.php(58): Magento\PageCache\Model\App\FrontController\BuiltinPlugin->aroundDispatch(Object(Magento\Framework\App\FrontController\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))\n#11 /data/www/.../.../vendor/magento/framework/Interception/Interceptor.php(138): Magento\PageCache\Model\App\FrontController\BuiltinPlugin\Interceptor->___callParent('aroundDispatch', Array)\n#12 /data/www/.../.../vendor/magento/framework/Interception/Interceptor.php(153): Magento\PageCache\Model\App\FrontController\BuiltinPlugin\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\FrontController\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))\n#13 /data/www/.../.../generated/code/Magento/PageCache/Model/App/FrontController/BuiltinPlugin/Interceptor.php(26): Magento\PageCache\Model\App\FrontController\BuiltinPlugin\Interceptor->___callPlugins('aroundDispatch', Array, Array)\n#14 /data/www/.../.../vendor/magento/framework/Interception/Interceptor.php(135): Magento\PageCache\Model\App\FrontController\BuiltinPlugin\Interceptor->aroundDispatch(Object(Magento\Framework\App\FrontController\Interceptor), Object(Closure), Object(Magento\Framework\App\Request\Http))\n#15 /data/www/.../.../vendor/magento/framework/Interception/Interceptor.php(153): Magento\Framework\App\FrontController\Interceptor->Magento\Framework\Interception\{closure}(Object(Magento\Framework\App\Request\Http))\n#16 /data/www/.../.../generated/code/Magento/Framework/App/FrontController/Interceptor.php(26): Magento\Framework\App\FrontController\Interceptor->___callPlugins('dispatch', Array, Array)\n#17 /data/www/.../.../vendor/magento/framework/App/Http.php(135): Magento\Framework\App\FrontController\Interceptor->dispatch(Object(Magento\Framework\App\Request\Http))\n#18 /data/www/.../.../generated/code/Magento/Framework/App/Http/Interceptor.php(24): Magento\Framework\App\Http->launch()\n#19 /data/www/.../.../vendor/magento/framework/App/Bootstrap.php(257): Magento\Framework\App\Http\Interceptor->launch()\n#20 /data/www/.../.../index.php(40): Magento\Framework\App\Bootstrap->run(Object(Magento\Framework\App\Http\Interceptor))\n#21 {main}","url":"/customer/section/load/?sections=cart&update_section_id=false&_=1547830571669","script_name":"/index.php"}

Answer 1

The reason is your modules have action process data in upgrade/install module.

Firstly: Find your modules process that script.

After that, add a area code to file update/install:

private $state;

public function __construct(\Magento\Framework\App\State $state) {
    $this->state = $state;
    parent::__construct();
}

public function execute() {
    $this->state->setAreaCode(\Magento\Framework\App\Area::AREA_FRONTEND); // or \Magento\Framework\App\Area::AREA_ADMINHTML, depending on your needs
}