deployer/recipe/magento2.php

<?php
namespace Deployer;

require_once __DIR__ . '/common.php';

use Deployer\Exception\RunException;
use Deployer\Host\Host;

const CONFIG_IMPORT_NEEDED_EXIT_CODE = 2;
const DB_UPDATE_NEEDED_EXIT_CODE = 2;
const MAINTENANCE_MODE_ACTIVE_OUTPUT_MSG = 'maintenance mode is active';

add('recipes', ['magento2']);

// Configuration

// By default setup:static-content:deploy uses `en_US`.
// To change that, simply put `set('static_content_locales', 'en_US de_DE');`
// in you deployer script.
set('static_content_locales', 'en_US');

set('content_version', function () {
    return time();
});

set('shared_files', [
    'app/etc/env.php',
    'var/.maintenance.ip',
    'var/.maintenance.flag'
]);
set('shared_dirs', [
    'var/composer_home',
    'var/log',
    'var/export',
    'var/report',
    'var/import',
    'var/import_history',
    'var/session',
    'var/importexport',
    'var/backups',
    'var/tmp',
    'pub/sitemap',
    'pub/media'
]);
set('writable_dirs', [
    'var',
    'pub/static',
    'pub/media',
    'generated'
]);
set('clear_paths', [
    'generated/*',
    'pub/static/_cache/*',
    'var/generation/*',
    'var/cache/*',
    'var/page_cache/*',
    'var/view_preprocessed/*'
]);

set('magento_version', function () {
    // detect version
    $versionOutput = run('{{bin/php}} {{release_or_current_path}}/bin/magento --version');
    preg_match('/(\d+\.?)+(-p\d+)?$/', $versionOutput, $matches);
    return $matches[0] ?? '2.0';
});

set('maintenance_mode_status_active', function () {
    // detect maintenance mode active
    $maintenanceModeStatusOutput = run("{{bin/php}} {{release_or_current_path}}/bin/magento maintenance:status");
    return strpos($maintenanceModeStatusOutput, MAINTENANCE_MODE_ACTIVE_OUTPUT_MSG) !== false;
});

// Deploy without setting maintenance mode if possible
set('enable_zerodowntime', true);

// Tasks
desc('Compiles magento di');
task('magento:compile', function () {
    run('cd {{release_or_current_path}} && {{bin/composer}} dump-autoload -o');
    run("{{bin/php}} {{release_or_current_path}}/bin/magento setup:di:compile");
    run('cd {{release_or_current_path}} && {{bin/composer}} dump-autoload -o');
});

desc('Deploys assets');
task('magento:deploy:assets', function () {
    run("{{bin/php}} {{release_or_current_path}}/bin/magento setup:static-content:deploy --content-version={{content_version}} {{static_content_locales}}");
});

desc('Syncs content version');
task('magento:sync:content_version', function () {
    $timestamp = time();
    on(select('all'), function (Host $host) use ($timestamp) {
        $host->set('content_version', $timestamp);
    });
})->once();

before('magento:deploy:assets', 'magento:sync:content_version');

desc('Enables maintenance mode');
task('magento:maintenance:enable', function () {
    run("if [ -d $(echo {{current_path}}) ]; then {{bin/php}} {{current_path}}/bin/magento maintenance:enable; fi");
});

desc('Disables maintenance mode');
task('magento:maintenance:disable', function () {
    run("if [ -d $(echo {{current_path}}) ]; then {{bin/php}} {{current_path}}/bin/magento maintenance:disable; fi");
});

desc('Config Import');
task('magento:config:import', function () {
    $configImportNeeded = false;

    if(version_compare(get('magento_version'), '2.2.0', '<')) {
        //app:config:import command does not exist in 2.0.x and 2.1.x branches
        $configImportNeeded = false;
    } elseif(version_compare(get('magento_version'), '2.2.4', '<')) {
        //app:config:status command does not exist until 2.2.4, so proceed with config:import in every deploy
        $configImportNeeded = true;
    } else {
        try {
            run('{{bin/php}} {{release_or_current_path}}/bin/magento app:config:status');
        } catch (RunException $e) {
            if ($e->getExitCode() == CONFIG_IMPORT_NEEDED_EXIT_CODE) {
                $configImportNeeded = true;
            } else {
                throw $e;
            }
        }
    }

    if ($configImportNeeded) {
        if (get('enable_zerodowntime') && !get('maintenance_mode_status_active')) {
            invoke('magento:maintenance:enable');
        }

        run('{{bin/php}} {{release_or_current_path}}/bin/magento app:config:import --no-interaction');

        if (get('enable_zerodowntime') && !get('maintenance_mode_status_active')) {
            invoke('magento:maintenance:disable');
        }
    }
});

desc('Upgrades magento database');
task('magento:upgrade:db', function () {
    $databaseUpgradeNeeded = false;

    try {
        run('{{bin/php}} {{release_or_current_path}}/bin/magento setup:db:status');
    } catch (RunException $e) {
        if ($e->getExitCode() == DB_UPDATE_NEEDED_EXIT_CODE) {
            $databaseUpgradeNeeded = true;
        } else {
            throw $e;
        }
    }

    if ($databaseUpgradeNeeded) {
        if (get('enable_zerodowntime') && !get('maintenance_mode_status_active')) {
            invoke('magento:maintenance:enable');
        }

        run("{{bin/php}} {{release_or_current_path}}/bin/magento setup:upgrade --keep-generated --no-interaction");

        if (get('enable_zerodowntime') && !get('maintenance_mode_status_active')) {
            invoke('magento:maintenance:disable');
        }
    }
});

desc('Flushes Magento Cache');
task('magento:cache:flush', function () {
    run("{{bin/php}} {{release_or_current_path}}/bin/magento cache:flush");
});

desc('Magento2 deployment operations');
task('deploy:magento', [
    'magento:build',
    'magento:config:import',
    'magento:upgrade:db',
    'magento:cache:flush',
]);

desc('Magento2 build operations');
task('magento:build', [
    'magento:compile',
    'magento:deploy:assets',
]);

desc('Deploys your project');
task('deploy', [
    'deploy:prepare',
    'deploy:vendors',
    'deploy:clear_paths',
    'deploy:magento',
    'deploy:publish',
]);

after('deploy:failed', 'magento:maintenance:disable');