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If you want to change the way an existing Drush command works you use hooks. Hooks are useful for altering command parameters, options, annotation data, and adding custom logic during particular stages of the command execution process. Drush hooks are conceptually similar to Drupal hooks.
Hooks are methods on a Drush command class with an annotation indicating what hook is being implemented, and thus when the code should be invoked. The code in the methods is executed during specific stages of the command cycle. Developers can use core hooks -- predefined methods that come with Drush core -- or declare a custom hook that other commands can use.
In this tutorial we'll:
- Explore the different core Drush hooks
- Learn which hooks are called at what stage of the command cycle
- View example hook annotations and method implementations
By the end of this tutorial you'll know what types of core hooks are available to you and when they are called.
Adding logging and error handling are an important part of authoring Drush commands. Logs allow developers to get timely feedback from a command and inform users about potential alterations and flags, events to monitor, and the progress of long-running commands. Correct error handling allows for clean exits, meaningful error descriptions, and provides a path forward for developers to fix the errors and accomplish their goals.
In this tutorial we'll:
- Explore the different types of logging messages Drush commands can output
- Learn how to handle errors from within a Drush command
By the end of this tutorial you'll know what types of log messages you can use; how to log success messages, errors, or debug statements from a custom Drush command; and how to handle errors and exceptions.
When the logic of a command depends on user input, it's useful to set up an interactive questionnaire inside the command code. This allows you to provide the user with more context about the input they're providing, and ensure that you collect all the necessary values. This is especially useful when the command uses a pre-defined list of options and the values require memorization. An example of this is the drush cache-clear
command that comes with Drush core. It requires an argument indicating which cache to clear, which you can specify at the command line; however, if you invoke the command with no arguments it will present you with a list of cache bins to choose from and a UI for selecting one.
Drush 9+ can access the Input/Output (I/O) object via the $this->io()
method. This object -- an instance of \Drush\Style\DrushStyle
-- holds information about user-provided input, and utilities for manipulating that input. To ask a user a question, use an io()
object in the command callback method. It can take over the execution flow of the command as needed to stop and gather additional input. The I/O system has various methods for asking confirmation or choice questions such as confirm()
and choice()
.
In addition to prompting for input, the I/O object can be used to provide other styling to the command, like progress bars.
In this tutorial we'll:
- Learn how to prompt the user for additional input
- Process the user's answer as part of the command execution flow
By the end of this tutorial you should understand how to prompt a user for additional input for a custom Drush command.
While Drush empowers all Drupal users with its commands, it's even more powerful when used in combination with scripting solutions such as Composer and Bash. Scripts can be used to power post-deployment tasks like importing new configuration or clearing the cache, as part of CI processes to sync a database from one environment to another, to run background processes on the server such as imports and migrations, search indexing, running cron, and much more. If you want to write Bash (or any other scripts) that interact with a Drupal site, then Drush is the tool for you.
In this tutorial we'll:
- Learn how to use Drush commands within Composer and Bash scripts
- Learn how to chain multiple Drush commands together in a script
By the end of this tutorial you'll know how to use Drush as part of a script that automates common or tedious tasks.
When you manage many Drupal websites, you may perform repetitive tasks that are common across all of your sites. In our experience, this usually relates to having a personal preference for how certain tasks are accomplished. For example: maybe you like to make backups of the database and files in a specific way before testing upgrades, or you have a set of scripts for running scans of core web vitals. Although these tasks can be bundled into a custom module, it could be useful to create a site-wide Drush command instead. Site-wide commands can be installed with Composer, managed in a separate Git repository, and act as a project dependency. This way they are easy to maintain through a separate upstream. Changes to this code will be reflected on all the sites where it's used.
In this tutorial we'll:
- Declare a custom site-wide Drush command
- Demonstrate how to use Composer to manage a package that contains a Drush command
By the end of this tutorial you'll be able to create a site-wide Drush command and manage the code with Git and Composer.
Creating a container set to support Drupal development requires some specialized knowledge. Now that we understand containers, images, how to use Docker Compose (docker-compose
), and how to select images on Docker Hub, we're ready to build a container set to support Drupal development.
In this tutorial, we'll:
- Select images of software that we'll need to run Drupal
- Create a new Compose file
- Configure bind volumes and environment variables to support the site
- Test the configuration
See Dockerize an Existing Project if you already have Drupal installed.
Drupal has robust Cache API, and various caching layers (both internal and external to Drupal), that work together to decrease application load and boost performance. Drupal's APIs allow developers to declare the cacheability of data. How long can this be stored before it becomes stale? And under what conditions should it be invalidated? Drupal uses that information during the process of building a page to cache as much of the work it does as is possible so that it won't need to do it again. Additionally, Drupal bubbles up the cacheability data from everything required to build a page into HTTP response headers that caching layers external to Drupal can also use to cache the rendered HTML.
When these APIs are combined (and used appropriately), Drupal can be extremely fast for both anonymous and authenticated traffic. But doing so requires understanding the various caching layers, their roles, and their interconnections.
In this tutorial, we'll:
- Review the caching layers and systems behind them
- Learn about components of the Drupal cache system
By the end of this tutorial, you should have a broad understanding of the Drupal caching system, its layers, and a better understanding of where in the stack you should look to optimize for different scenarios.
Note: This tutorial is specific to Drupal sites hosted on the Acquia platform and covers integrating its features to improve performance.
The Acquia platform includes Memcache, Varnish, and Content Delivery Network (CDN) integration. In order for these to be as effective as possible, they should be configured and tuned for your specific use case. This tutorial provides an introduction to these utilities and common configuration. For more detail, you should consult the Acquia documentation.
In this tutorial, we'll:
- Learn what caching utilities are included in the Acquia platform
- Set up and tune different parts of Acquia's application caching level including Memcache and Varnish
By the end of this tutorial, you'll know what application-level caching options exist on Acquia's platform. And how to configure it, and your Drupal application, for better performance.
WebPageTest (webpagetest.org) is a free open source resource that runs performance tests on a site, provides educational reports about what it finds, and suggests optimizations you can make. The tests performed via the WebPageTest interface include Lighthouse tests, performance-specific tests, Core Web Vitals, visual comparisons, and traceroute tests. The tool also allows saving a history of tests if you sign up for a free account. This tool won't make your site faster on its own, but it will give you some good ideas about where to focus your efforts.
In this tutorial we'll:
- Learn how to run performance tests via the WebPageTest web interface
- Learn how to read and interpret the results
By the end of this tutorial, you should know how to use the WebPageTest online interface to analyze a Drupal site's performance.
Lighthouse is an open source, automated tool for analyzing your site's performance. Lighthouse is built-in to the Google Chrome browser. When auditing a page, Lighthouse runs various tests against the page and then reports how well the page did across a broad spectrum of metrics. While Lighthouse doesn't improve the performance of a Drupal site itself, it helps to establish a performance profile and point towards areas that could be improved.
Lighthouse requires the use of Google Chrome. Other browsers include their own performance auditing tools. While the exact usage of each tool varies, the end result is the same: a report that can be interpreted to suggest where to focus your performance-tuning efforts.
In this tutorial, we'll:
- Learn how to run Lighthouse tests against a Drupal site
- Interpret the results of the report generated by Lighthouse
- Provide guidance on next steps to take to address the performance issues Lighthouse finds in our Drupal site
By the end of this tutorial you should be able to use Lighthouse to profile a Drupal site, interpret the results, and know where to start on making improvements.
Content Delivery Networks (CDNs) play an important role in making a Drupal-powered site fast and secure. The distributed nature of CDNs allows serving web assets such as HTML files, JavaScript, CSS, and media assets through servers located in close geographical proximity to the users, thereby reducing the physical distance data has to travel between the user and the server, and improving performance.
In addition to providing a performance boost, CDNs may also act as a firewall and protect sites from common attacks such as DDoS. The popularity of CDNs has been growing over the past few years, and integrating with them has also gotten easier. Most Drupal web operation platforms, such as Acquia and Pantheon, offer integrations with CDNs out-of-the-box. Even if your hosting platform doesn't provide a CDN, you can always set up your Drupal site to use one.
In this tutorial we'll:
- Define what a CDN is and what it can offer for your site
- Learn about popular CDNs used with Drupal sites
- Review some contributed modules that you can use to help integrate your Drupal site with a CDN
By the end of this tutorial you should be able to define what a CDN is, list CDNs with Drupal integrations, and describe the steps you will need to take to set up your site to work with a CDN.
Drupal core is built with performance and scalability in mind. It is Fast by Default. But performance is often a by-product of your specific application, and depending on how you're using Drupal, you can further optimize your site using contributed modules. These modules range from debugging utilities to cache-related modules.
It's worthwhile to have a general idea of what's available in the contributed module space. And, when you need to address your site's unique performance needs, it helps if you already know about existing solutions.
In this tutorial we'll:
- Look at a few popular contributed modules that improve Drupal's performance
- Learn about the benefits these modules may provide to your site
- Provide tips on how to configure these modules
By the end of this tutorial you should be able to list some popular performance related Drupal modules and describe their use case.
Apache Bench (ab
) is a tool that comes with the commonly used Apache HTTP server. It is designed to give you an impression of how your current Apache installation performs. It will work for any HTTP server, not just Apache. Apache Bench shows you how many requests per second your server can serve. This metric is in part a measure of how long it takes Drupal (PHP) to process the request and create a response. While there are other things that the HTTP server does too, executing PHP is by far the most expensive when serving Drupal pages.
Therefore, Apache Bench helps profile your PHP code for new features, patches after their application, and PHP libraries used on the site. You can quickly compare before and after metrics as an indicator of the scale of the impact a change has.
In this tutorial, we'll:
- Learn how to run the Apache Bench tool on our local environment
- Learn to interpret the result of the tests
By the end of this tutorial, you should know how to benchmark and profile your local Drupal installation using Apache Bench (ab
).
Sites evolve over time. We're constantly adding and removing modules, modifying content, authoring custom plugins, and changing design elements. All of these changes impact our application's performance -- some more so than others. But if you're not measuring it, you can't know when your site inadvertently gets slower or by how much.
If you are responsible for a site's performance, it might be good to look into benchmarking it and establishing a performance budget early on, then monitor it on an ongoing basis. Many tools, paid and free, allow measuring key web performance indicators and backend code and server performance.
One-time measurements can be useful for immediate debugging, or when figuring out if that big new feature is going to have a negative impact on performance. But for long-term projects, it's helpful to have known baseline values and an established performance budget to see whether your performance improves or declines over time with every new feature.
Establishing the baseline (performance budget) and comparing future measurements is called site performance benchmarking.
In this tutorial, we'll:
- Learn the basics concepts of benchmarking
- Learn a benchmarking process and best practices
- List some commonly used tools for benchmarking Drupal
By the end of this tutorial, you should understand the concept of a performance budget, know when to benchmark your site, and list some tools available to help.
Pantheon uses its Object Cache and Global CDN services to help improve the performance of your Drupal sites. Using them requires a few steps to enable the services and configure your Drupal site to use them effectively.
Many performance optimizations are hosting-provider-specific. This tutorial covers some Pantheon-specific methods for increasing your Drupal site's performance. It's only relevant if your site is hosted on Pantheon. For other common providers, and generic performance tuning tips, refer to other tutorials in this course.
In this tutorial we'll:
- Learn how to configure and use Pantheon's Object Cache to speed up Drupal caching
- Learn about the use case for Pantheon's Advanced Page Cache module
- Install and configure the Advanced Page Cache module for better Drupal caching of sites hosted on Pantheon
By the end of this tutorial you should be able to explain when and why you would want to use Pantheon's Object Cache and Advanced Page Cache modules, and how they can help speed up Drupal sites hosted on Pantheon.
Over the history of the Internet, the single Page Speed metric evolved into various parameters that influence user experience. These metrics are commonly referred to as Core Web Vitals. Together, they paint a comprehensive picture of the performance of your site from an end user's perspective. These metrics are considered by Google and other search engines when assigning SEO scores.
Knowing what these metrics are, and what they are intended to measure, is an important part of creating a performance profile for your site. This knowledge can also help you find solutions for common performance issues.
In this tutorial, we'll:
- Define the metrics that make up the Core Web Vitals
- Point to additional resources where you can learn more about each metric
By the end of this tutorial, you should know which performance metrics are considered Core Web Vitals and what aspects of site performance they cover.
The performance optimization settings and modules provided by Drupal core are intended to work for the broadest possible set of use cases. From an administrator's perspective they provide minimal configuration options, and are designed to just work by being enabled. But behind that simplicity are some powerful features that will help speed up any Drupal-powered application.
The core Dynamic Page Cache and Internal Page Cache modules are designed to provide a base cache setup for any site. These modules are responsible for the static page cache, dynamic page cache, and lazy loading optimizations.
For developers, Drupal provides a complete and well-designed Cache API. You can, and should, integrate it into your custom code. This integration includes defining the cacheability of any content your module outputs so that Drupal can be smart about how that affects how and when a page that incorporates the output can be cached -- as well as storing and retrieving the results of complex or long-running operations. The API also helps with setting appropriate HTTP headers for the responses Drupal generates for each request so that the user's browser and other layers in the stack can appropriately cache the output.
The entire system is flexible, and there are many contributed modules that can aid in making the default caching system even faster for specific use cases.
In this tutorial, we'll:
- Learn about the caching-related modules in Drupal core
- Review the Drupal core performance settings and recommended values
By the end of this tutorial you should be familiar with the Drupal core modules responsible for caching, their settings, and recommended values.
There's no magical set of right tools to use to monitor a Drupal site's performance and health. While thinking about performance monitoring, you need to optimize your approach depending on the number of applications you manage, their complexity, business needs, and the skill-set of your team. Based on these factors, you may choose to use one of the core or contributed modules, go with third-party solutions and services, or some combination of both.
Drupal core comes with a couple of modules that allow you to monitor the health and performance of the site including Syslog, Database Logging, and the status reports provided by the System module. There are also numerous community-contributed modules, a sampling of which we'll cover here.
In this tutorial, we'll:
- List some contributed modules that are commonly used for monitoring a Drupal site
- Provide an overview of what each module does
By the end of this tutorial you should be able to list a few contributed modules that might be useful for monitoring your Drupal application and define what each one does.
New Relic is a monitoring service that provides insights into your application stack from front-end performance to the server and infrastructure metrics. New Relic uses a combination of aggregating server logs, and pre-built (or custom) monitors to track the metrics that are most important to your application. The collected data can be organized into custom dashboards, and alerts can be set up and issued per customizable conditions.
In this tutorial, we'll:
- Learn about different New Relic modules and their purpose
- Review some default dashboard components and reports
- Discuss how to use the information in New Relic to understand the health of your Drupal application
By the end of this tutorial, you should understand the basics of using New Relic and the insights it offers to monitor and improve the performance of your Drupal site.
Performance profiling allows you to see an overview of how your Drupal application stacks up against your users' needs and business requirements. A good profile will help you understand where the performance bottlenecks are and where you should focus your efforts in order to achieve the best results when optimizing your application.
There are many profiling tools available to help you analyze your Drupal site's performance. Some are free -- like the browser’s built-in development tools, the Lighthouse Chrome extension, and XHProf. Some are paid -- like New Relic, Blackfire, and other profiling SaaS solutions.
In this tutorial we'll:
- Outline the general concepts and goals of performance profiling
- List some available profiling tools and their features
By the end of this tutorial you should be able to describe what performance profiling is, and list the tools commonly used to establish a performance profile for a Drupal site.