I feel lucky to be a part of creating and building Drupal. According to BuiltWith, Drupal powers 2.8% of websites in the top 1 million. That translates to 1 out of 35 websites. I've been thinking about what that means in terms of real impact: if any of the 3.2 billion internet users today have visited 35 or more of the top 1 million websites, they've "used" Drupal. I imagine most active internet users have visited more than 35 websites, and as such, Drupal must have "reached" almost everyone on the internet. That is a pretty incredible thought.
I've heard so many amazing stories about how Drupal sites have been a part of cultural, social and political movements. One of the stories that I'll never forget is from the Egyptian uprising in 2011, when the internet shut down for days and people took to the streets in protest of the Mubarak regime. This moment showed the profound impact of the web and the injustice citizens feel when it is taken away. The Drupal site Al Jazeera was an essential news source on this uprising for the rest of the world and remained online despite traffic to its live blog spiking 2,000 percent during the crisis.
Another such story is that of the Global Disaster Preparedness Center (GDPC), whose 189 partner organizations (including the American Red Cross) needed a better way to collaborate on disaster relief issues. GDPC embraced Open Source and built a multilingual Drupal site where disaster preparedness professionals can share information and resources that otherwise wouldn't be available. Considering the recent rise in natural disasters, this information has saved lives.
These two stories show how the web has the power to change lives, fuel economies, educate the masses and make the world much smaller in the best of ways. According to Cisco, Internet traffic in 2019 will be 64 times the volume in 2005. It is expected that another 1.8 billion people could come online by the end of 2018.
Yesterday, we announced the first Drupal 8 release candidate after almost five years of hard work by thousands of people in our community. The road towards Drupal 8 has been long and hard, but I'm excited that Drupal 8 will touch the next billion people who join the internet. They are joining fast. I hope you'll share stories of the impact Drupal has made on your lives as we continue to grow.
Today, we announce Drupal 8.0.0 RC1, the first Drupal 8 release candidate. It's a very exciting milestone, and one that has taken a lot of hard work, long nights, weekends, and extreme commitment from our community. I appreciate the dedication of everyone involved, and understand what it takes to give up personal time in pursuit of building something greater. So, for that I want to thank you.
In total, Drupal 8 has had more than 3,200 contributors and 15,000 committed patches. The good news is, we've finally reached the day when Drupal 8 has hit zero release-blocking bugs and is ready for takeoff!
Historically, the adoption of Drupal has roughly doubled with each new release. We expect no different from Drupal 8, a release I believe positions Drupal most strongly for the future. We've undergone some big architectural changes to get more people using Drupal, and to prepare ourselves for the future. I can't wait to see what the community does with Drupal 8. It's time to start building!
Today, we're excited to announce that Acquia has closed a $55 million financing round, bringing total investment in the company to $188.6 million. Led by new investor Centerview Capital Technology, the round includes existing investors New Enterprise Associates (NEA) and Split Rock Partners.
We are in the middle of a big technological and economic shift, driven by the web, in how large organizations and industries operate. At Acquia, we have set out to build the best platform for helping organizations run their businesses online, help them invent new ways of doing business, and maximize their digital impact on the world. What Acquia does is not at all easy -- or cheap -- but we've made good strides towards that vision. We have become the backbone for many of the world's most influential digital experiences and continue to grow fast. In the process, we are charting new territory with a very unique business model rooted Drupal and Open Source.
A fundraise like this helps us scale our global operations, sales and marketing as well as the development of our solutions for building, delivering and optimizing digital experiences. It also gives us flexibility. I'm proud of what we have accomplished so far, and I'm excited about the big opportunity ahead of us.
Of all the trends in the web community, few are spreading more rapidly than decoupled (or "headless") content management systems (CMS). The evolution from websites to more interactive web applications and the need for multi-channel publishing suggest that moving to a decoupled architecture that leverages client-side frameworks is a logical next step for Drupal. For the purposes of this blog post, the term decoupled refers to a separation between the back end and one or more front ends instead of the traditional notion of service-oriented architecture.
Traditional ("monolithic") versus fully decoupled ("headless") architectural paradigm.
Decoupling your content management system enables front-end developers to fully control an application or site's rendered markup and user experience. Furthermore, the use of client-side frameworks helps developers give websites application-like behavior with smoother interactivity (there is never a need to hit refresh, because new data appears automatically), optimistic feedback (a response appears before the server has processed a user's query), and non-blocking user interfaces (the user can continue to interact with the application while portions are still loading).
Another advantage of a decoupled architecture is decoupled teams. Since front-end and back-end developers no longer need to understand the full breadth and depth of a monolithic architecture, they can work independently. With the proper preparation, decoupled teams can improve the velocity of a project.
Still, it's important to temper the hype around decoupled content management with balanced analysis. Before decoupling, you need to ask yourself if you're ready to do without functionality usually provided for free by the CMS, such as layout and display management, content previews, user interface (UI) localization, form display, accessibility, authentication, crucial security features such as XSS (cross-site scripting) and CSRF (cross-site request forgery) protection, and last but not least, performance. Many of these have to be rewritten from scratch, or can't be implemented at all, on the client-side. For many projects, building a decoupled application or site on top of a CMS will result in a crippling loss of critical functionality or skyrocketing costs to rebuild missing features.
To be clear, I'm not arguing against decoupled architectures per se. Rather, I believe that decoupling needs to be motivated through ample research. Since it is still quite early in the evolution of this architectural paradigm, we need to be conscious about how and in what scenarios we decouple. In this blog post, we examine different decoupled architectures, discuss why a fully decoupled architecture is not ideal for all use cases, and present "progressive decoupling", a better approach for which Drupal 8 is well-equipped. Today, Drupal 8 is ready to deliver pages quickly and offers developers the flexibility to enhance user experience through decoupled interactive components.
Fully decoupled is not usually the best solution
In a fully decoupled architecture, the theme layer is often ignored altogether, and many content management capabilities are lost, though many clients ingesting data are possible.
Traditionally, CMSes have focused on making websites rather than web applications, but the line between them continues to blur. For example, let's imagine we are building a site delivering content-rich curated music reviews alongside an interaction-rich ticketing interface for live shows. In the past, this ticketing interface would have been a multi-step flow, but here we aim to keep visitors on the same page as they browse and purchase ticket options.
To write and organize reviews, beyond basic content management, we need site building tools to assemble content and lay it out on a page. On the other hand, for a pleasant ticket purchase experience, we need seamless interactivity. From the end user's perspective, this means a continuous, uninterrupted experience using the application and best of all, no need to refresh the page.
In a fully decoupled architecture, our losses from having to rebuild what Drupal gives us for free outweigh the wins from client-side frameworks. With a fully decoupled front end, we lose important aspects of the theme layer (which is tightly intertwined with Drupal APIs) such as theme hook suggestions, Twig templating, and, to varying degrees, the render pipeline. We lose content preview and nuances of creating, curating, and composing content such as layout management tools. We lose all of the advancements in accessibility and user experience that make Drupal 8 websites a great tool for both end users and site builders, like ARIA roles, improved system messages, and, most visibly, the fully integrated Drupal toolbar on non-administrative pages. Moreover, where there is elaborate interactivity, security vulnerabilities are easily introduced.
Progressive rendering with BigPipe
Fully decoupled architectures can also have a performance disadvantage. We want users to see the information they want as soon as possible (time to first paint) and be able to perform a desired action as soon as possible (time to interaction). A well-architected CMS will have the advantage over a client-side framework.
Much of the content we want to send for our music website is cacheable and mostly static, such as a navigation bar, recurring footer, and other unchanging components. Under a traditional page serving model, however, operations taking longer to execute can hold up simpler parts of the page in the pipeline and significantly delay the response to the client. In our music site example, this could be blocks containing songs a user listened to most in the last week and the song currently playing in a music player.
What we really need is a means of selectively processing those expensive components later and sending the less intensive bits earlier. With BigPipe, an approach for client-side dynamic content substitution, we can render our pages progressively, where the skeleton of the page loads first, then expensive components such as "songs I listened to most in the last week" or "currently playing" are sent to the browser later and fill out placeholders. This component-driven approach gives us the best of both worlds: non-blocking user interfaces with a brisk time to first interaction and rapid piecemeal loading of complete Drupal pages that leverage the theme layer.
Currently, Drupal 8 is the only CMS with BigPipe deeply integrated across the board for both core and contributed modules—they merely have to provide some cacheability metadata and need no awareness of the technical minutiae. Drupal 8's Dynamic Page Cache module ensures that the page skeleton is already cached and can thus be sent immediately. For example, as menus are identical for many users, we can reuse the menu for those users that can access the same menu links, so Dynamic Page Cache is able to cache those as part of the page skeleton. On the other hand, a personalized block with a user's most played songs is less effective to cache and will therefore be rendered after the page skeleton is sent. This cacheability is built into core, and every contributed module is required to provide the necessary metadata for it.
Client-side frameworks encounter some critical and inescapable drawbacks of conducting all rendering on the client side. On slow connections such as on mobile devices, client-side rendering slows down performance, depletes batteries faster, and forces the user to wait. Because most developers test locally and not in real-world network conditions on actual devices, it's easy to forget that real risks of sluggishness and unreliability, especially due to spotty connectivity, continue to confront any fully decoupled site — Drupal or otherwise.
Progressive decoupling is the future
Under progressive decoupling, the CMS renderer still outputs the skeleton of the page.
As we've seen, fully decoupling eliminates crucial CMS functionality and BigPipe rendering. But what if we could decouple while still having both? What if we could keep things like layout management, security, and accessibility when decoupling while still enjoying all the benefits an interaction-rich single-page application would give us? More importantly, what if we could take advantage of BigPipe to leverage shortened times to interaction and lowered obstacles for heavily personalized content? The answer lies in decoupled components, or progressive decoupling. Instead of decoupling the entire page, why not decouple only portions of it, like individual blocks?
This component-driven decoupled architecture comes with big benefits over a fully decoupled architecture. Namely, traditional content management and workflow, display and layout management are still available to site builders. To return to our music website example, we can drag a block containing the songs a user listened to most in the past week into an arbitrarily located region on the page; a front-end developer can then infuse interactivity such that an account holder can play a song from that list or add it to a favorites list on the fly. Meanwhile, if a content creator wants to move the "most listened to in the past week" block from the right sidebar of the page to the left side of the page, she can do that with a few mouse clicks, rather than having to get a front-end developer involved.
We call this approach progressive decoupling, because you decide how much of the page and which components to decouple from Drupal's front end or dedicated Drupal renderings. For this reason, progressively decoupled Drupal brings decoupling to the assembled web, something I'm very passionate about, because empowering site builders and administrators to build great websites without (much) programming is important. Drupal is uniquely capable for this, precisely because it allows for varying degrees of decoupledness.
Drupal 8 is ahead of the competition and is your go-to platform for building decoupled websites. It comes with a built-in REST API for all content, a system to query data from Drupal (e.g. REST exports in the Views module), and a BigPipe implementation. It will be even better once the full range of contributed modules dealing with REST is available to developers.
With Drupal 8, an exciting spectrum opens up beyond just the two extremes of fully decoupling and traditional Drupal. As we've seen, fully decoupling opens the door to a Drupal implementation providing content to a broad range of one or more clients ("many-headed" Drupal), such as mobile applications, interactive kiosks, and television sets. But progressive decoupling goes a step further, since you can fully decouple and progressively decouple a single Drupal site with all the tools to assemble content still intact.
What is next for decoupling in Drupal?
In the case of many-headed Drupal, fully decoupled applications can live alongside progressively decoupled pages, whose skeletons are rendered through the CMS.
Although Drupal has made huge strides in the last few years and is ahead of the competition, there is still work to do. Traditional Drupal, fully decoupled Drupal, and progressively decoupled Drupal can all coexist. With improved decoupling tools, Drupal can be an even better hub for many heads: a collection of applications and sites linked and supported by a single backend.
One of the most difficult issues facing front-end developers is network performance with REST. For example, a REST query fetching multiple content entities requires a round trip to the server for each individual entity, each of which may also depend on relational data such as referenced entities that require their own individual requests to the server. Then, to gather the required data, each REST query needs a corresponding back-end bootstrap, which can be quite hefty. Such a large stack of round trips and bootstraps can be prohibitively expensive.
Beyond performance and endpoint management, developer experience also suffers under a RESTfully decoupled Drupal architecture. For each individual request, there is a single corresponding schema for the response that is immutable. In order to retrieve differently formatted or filtered data according to your needs, you must create a second variant of a given endpoint or provision a new endpoint altogether. Front-end developers concerned about performance limitations desire full control from the client side over what schema comes back and want to avoid working with the server side.
Decoupling thus reveals the need to investigate better ways of exposing data to the client side. As our pages and applications become ever more component-driven, the complexity of the queries we must perform and our demands on their performance increase. What if we could extract only the data we need by writing queries that are efficient and performant by default? Sebastian Siemssen proposes using Facebook's GraphQL (see demo video and project on drupal.org) due to the client's explicit definition of what schema to return and the use of consolidated queries which break apart into smaller calls and recombine for the response, thereby minimizing round trips.
I like GraphQL's approach for both fully and progressively decoupled front-ends. It means that decoupled sites will enjoy better overall performance and give front-end developers a better experience: very few round trips to the server, no need for custom endpoints, no need for versioning, and no dependence on back-end developers. (I even wonder if GraphQL could be the basis for a future version of Views.)
In addition, work on rendering improvements such as BigPipe should continue in order to explore the possibilities given a more progressive rendering system. It's currently in progress to accelerate Drupal's perceived page loads where users consume expensive or personalized content. As for tools within the administration layer and in the contributed space, further progress in Drupal 8 is also necessary for layout management tools such as Panels and block placement that would make decoupling at a granular level much easier.
A great deal is being done, but we could always use more help; please get in touch if you're interested in contributing code or funding our work. After all, the potential impact of progressive rendering on the future of decoupled Drupal is huge.
Decoupled content management is a rapidly evolving trend that has the potential to upend existing architectural paradigms. Nonetheless, we need to be cautious when approaching decoupled projects due to the loss of functionality and performance.
With Drupal 8, we can use progressive rendering to build a Drupal-driven skeleton of the page to fill out increasingly expensive portions of the page. We can then selectively delineate which parts of the page decouple once the page load is complete. This concept of progressive decoupling offers the best of both worlds. Layout management, security, and content previews are unaffected, and within page components, front-end application logic can work its magic.
Drupal 8 is now a state-of-the-art platform for building projects that lie at the nexus between traditional content-rich websites and modern interaction-rich web applications. As always, while remarkable strides have been made with Drupal 8, more work remains.
Special thanks to Preston So and Wim Leers at Acquia for contributions to this blog post and to Moshe Weitzman, Kevin O'Leary, Christian Yates, David Hwang, Michael Pezzi and Erik Baldwin for their feedback during its writing.
Drupal will soon be 15 years old, and 5 of that will be spent on building Drupal 8 -- a third of Drupal's life. We started work on Drupal early in 2011 and targeted December 1, 2012 as the original code freeze date. Now almost three years later, we still haven't released Drupal 8. While we are close to the release of Drupal 8, I'm sure many many of you are wondering why it took 3 years to stabilize. It is not like we didn't work hard or that we aren't smart people. Quite the contrary, the Drupal community has some of the most dedicated, hardest working and smartest people I know. Many spent evenings and weekends pushing to get Drupal 8 across the finish line. No one individual or group is to blame for the delay -- except maybe me as the project lead for not having learned fast enough from previous release cycles.
The past 15 years we used "trunk-based development"; we built new features in incremental steps, maintained in a single branch called "trunk". We'd receive the feature's first patch, commit it to our main branch, put it behind us, and move on to the next patch. Trunk-based development requires a lot of discipline and as a community we have mostly mastered this style of development. We invested heavily in our testing infrastructure and established a lot of processes. For all patches, we had various people reviewing the work to make sure it was solid. We also had different people figure out and review all the required follow-up work to complete the feature. The next steps are carefully planned and laid out for everyone to see in what we call "meta" issues. The idea of splitting one large feature into smaller tasks is not a bad idea; it helps to make things manageable for everyone involved.
Given all this rigor, how do you explain the delays then? The problem is that once these features and plans meet reality, they fall apart. Some features such as Drupal 8's configuration management system had to be rewritten multiple times based on our experience using it despite passing a rigorous review process. Other features such as our work on URL routing, entity base fields and Twig templating required much more follow-up work compared to what was initially estimated. It turns out that breaking up a large task into smaller ones requires a lot of knowledge and vision. It's often impossible to estimate the total impact of a larger feature on other subsystems, overall performance, etc. In other cases, the people working on the feature lacked time or interest to do the follow-up work, leaving it to others to complete. We should realize is that this is how things work in a complex world and not something we are likely to change.
The real problem is the fact that our main branch isn't kept in a shippable state. A lot of patches get committed that require follow-up work, and until that follow-up work is completed, we can't release a new version of Drupal. We can only release as fast as the slowest feature, and this is the key reason why the Drupal 8 release is delayed by years.
Trunk-based development; all development is done on a single main branch and as a result we can only release as fast as the slowest feature.
We need a better way of working -- one that conforms to the realities of the world we live in -- and we need to start using it the day Drupal 8.0.0 is released. Instead of ignoring reality and killing ourselves trying to meet unrealistic release goals, we need to change the process.
Feature branch workflow
The most important thing we have to do is keep our main branch in a shippable state. In an ideal world, each commit or merge into the main branch gives birth to a release candidate — it should be safe to release after each commit. This means we have to stop committing patches that put our main branch in an unshippable state.
While this can be achieved using a trunk-based workflow, a newer and better workflow called "feature branch workflows" has become popular. The idea is that (1) each new feature is developed in its own branch instead of the main branch and that (2) the main branch only contains shippable code.
Keeping the main branch shippable at all times enables us to do frequent date-based releases. If a specific feature takes too long, development can continue in the feature branch, and we can release without it. Or when we are uncertain about a feature's robustness or performance, rather than delaying the release, it will simply have to wait until the next release. The maintainers decide to merge in a feature branch based on objective and subjective criteria. Objectively, the test suite must pass, the git history must be clean, etc. Subjectively, the feature must deliver value to the users while maintaining desirable characteristics like consistency (code, API, UX), high performance, etc.
Feature branching; each feature is developed in a dedicated branch. A feature branch is only merged into the main branch when it is "shippable". We no longer have to wait for the slowest feature before we can create a new release.
Date-based releases are widely adopted in the Open Source community (Ubuntu, OpenStack, Android) and are healthy for Open Source projects; they reduce the time it takes for a given feature to become available to the public. This encourages contribution and is in line with the "release early, release often" mantra. We agreed on the benefits and committed to date-based releases following 8.0.0, so this simply aligns the tooling to make it happen.
Feature branch workflows have challenges. Reviewing a feature branch late in its development cycle can be challenging. There is a lot of change and discussion already incorporated. When a feature does finally integrate into main, a lot of change hits all at once. This can be psychologically uncomfortable. In addition, this can be disruptive to the other feature branches in progress. There is no way to avoid this disruption - someone has to integrate first. Release managers minimize the disruption by prioritizing high priority or low disruption feature branches over others.
Here is a workflow that could give us the best of both worlds. We create a feature branch for each major feature and only core committers can commit to feature branches. A team working on a feature would work in a sandbox or submit patches like we do today. Instead of committing patches to the main branch, core committers would commit patches to the corresponding feature branch. This ensures that we maintain our code review process with smaller changes that might not be shippable in isolation. Once we believe a feature branch to be in a shippable state, and it has received sufficient testing, we merge the feature branch into the main branch. A merge like this wouldn't require detailed code review.
Feature branches are also not the silver bullet to all problems we encountered with the Drupal 8 release cycle. We should keep looking for improvements and build them into our workflows to make life easier for ourselves and those we are implementing Drupal for. More on those in future posts.