Magento 2: programmatically run setup upgrade

Question

My Client wants me to write code to :

1. programmatically upload a customized module and then
2. enable the module(php bin/magento module:enable VENDORNAME_MODULENAME) and then
3. upgrade the system(php bin/magento setup:upgrade).

I successfully did the first 2 steps, but unable to do the 3rd one. Can anyone share sample code to programmatically run setup upgrade in Magento 2?

 <?php  
        use Magento\Framework\App\Bootstrap;
        include('../app/bootstrap.php');
        $bootstrap = Bootstrap::create(BP, $_SERVER);
        $objectManager = $bootstrap->getObjectManager();

        $modules = array('VENDORNAME_MODULENAME');
        try{
            // Code to enable the module
            $objectManager->create('Magento\Framework\Module')->setIsEnabled(true,$modules);

            // Code to setup upgrade(php bin/magento setup:upgrade)
            .......

        }catch(Exception $e){
            $msg = 'Error : '.$e->getMessage();die();
        }

Answer 1

<?php
    use Magento\Framework\App\Bootstrap;
    include('../app/bootstrap.php');
    $bootstrap = Bootstrap::create(BP, $_SERVER);
    $objectManager = $bootstrap->getObjectManager();


    $modules = array('VENDORNAME_MODULENAME');
    try{
        /* Code to enable a module [ php bin/magento module:enable VENDORNAME_MODULENAME ] */
        $moduleStatus = $objectManager->create('Magento\Framework\Module\Status')->setIsEnabled(true,$modules);


        /* Code to run setup upgrade [ php bin/magento setup:upgrade ] */
        $installerFactory = $objectManager->create('Magento\Setup\Test\Unit\Console\Command\UpgradeCommandTest')->testExecute();


        /* Code to clean cache [ php bin/magento:cache:clean ] */
        try{
            $_cacheTypeList = $objectManager->create('Magento\Framework\App\Cache\TypeListInterface');
            $_cacheFrontendPool = $objectManager->create('Magento\Framework\App\Cache\Frontend\Pool');
            $types = array('config','layout','block_html','collections','reflection','db_ddl','eav','config_integration','config_integration_api','full_page','translate','config_webservice');
            foreach ($types as $type) {
                $_cacheTypeList->cleanType($type);
            }
            foreach ($_cacheFrontendPool as $cacheFrontend) {
                $cacheFrontend->getBackend()->clean();
            }
        }catch(Exception $e){
            echo $msg = 'Error during cache clean: '.$e->getMessage();die();
        }   
    }catch(Exception $e){
        echo $msg = 'Error during module enabling : '.$e->getMessage();die();
    }

Answer 2

To do so you need to use the Magento/Setup/Model/InstallerFactory class.

For example this is the code that runs when you call the CLI command:

    $keepGenerated = $input->getOption(self::INPUT_KEY_KEEP_GENERATED);
    $installer = $this->installerFactory->create(new ConsoleLogger($output));
    $installer->updateModulesSequence($keepGenerated);
    $installer->installSchema();
    $installer->installDataFixtures();
    if (!$keepGenerated) {
        $output->writeln('<info>Please re-run Magento compile command</info>');
    }