What is continuous delivery, and how can it help you?

As anyone who’s ever impatiently stared at an ‘installing updates’ message will tell you, waiting for your software to get itself together is a pain. Long wait times, lengthy repairs, and frequent bugs are the stuff of nightmares for users and developers alike.

Previously, developers worked in isolation for a set period, then merged their work with the master branch once their batch was complete. Delivering code changes was time-consuming and often created bugs.

A solution arose that shortened the time between releases, making delivery faster and more frequent. The process is called continuous delivery, and it’s by far the most popular way of working for app developers today. But before we jump into what it is, we first need to understand continuous integration (CI).

What is continuous integration (CI)?

Continuous integration refers to the practice of merging code changes into a central repository. Once complete, the team can run automated builds and tests at the click of a button. This level of automation helps developers find bugs faster. It also improves quality and shortens the amount of time between new releases.

What is continuous delivery (CD)?

Continuous delivery (also known as CD) expands upon continuous integration by deploying all code changes to a testing environment immediately after the build stage. Once the build has passed the test, designers have a deployment-ready item that has passed through a standardized test process.

Continuous delivery allows developers to test multiple aspects – from API reliability to load testing to UI. It enables developers to preemptively spot issues and validate their choices. This boosts developer confidence and speeds up the time it takes to have a usable build ready.

Some of the benefits of continual delivery:

• Releasing quickly and often gives the end-user a chance to provide their feedback.
• Revisions will be smaller, and less likely to impact other features.
• It involves non-developers into the build process, giving dev teams valuable and direct insight into how the product will be used.
• As a way of working, it promotes cross-team collaboration because fast releases rely on a great deal of communication and transparency between all team members.
• It provides greater insight into a design’s metrics, including engagement rates, time spent between each design phase, bug encounter rates, and new feature release frequencies.
• It also offers greater insight into team performance metrics, which makes it easier to define KPIs and generally gain greater insight into the health of your processes and practices.

What’s the difference between continuous delivery and continuous deployment?

The acronyms are the same (CD x2), but there’s a subtle difference. With continuous deployment, the software is produced in short cycles through automated deployments. With continuous delivery, the deployments are manual.

Continuous delivery

Continuous delivery means that you are ready and able to deploy any version to any supported platform at any time, simply by clicking a button. On top of automating your testing, you’ve also automated your release process.

In the true spirit of continuous delivery, you should deploy your releases in small batches as early as possible. That way, issues are smaller and easier to fix.

Continuous deployment

With continuous deployment, there is no human interaction: you only know there’s an issue when there’s a failed test, which will stop you from moving on to the next stage.

It allows you to speed up the feedback loop while taking pressure off the dev team. With no ‘release day’ date hanging over them, they’re free to design and build and see their work go live in a continual loop.

Essential continuous delivery principles you need to know

There are eight fundamental principles to continual delivery, and the more your team can carry out each of these, the more effective your workflow will be.

1. Automate everything

Speed things up by automating as much as possible (while still retaining control over the release). Automation gives dev teams and managers more time to spend on more creative tasks, like designing and finding new ways of solving customer problems. Letting computers take over also increases reliability. To err is to human, after all…

2. Make sure you have version control

Version control is a vital and essential part of CD. Why? Because you need to make sure you can keep adding versions without impacting existing features.

Version or source control backs up your SQL code and allows for continuous development and integration, which is a crucial component of continuous delivery. As well as keeping everyone on the same page, it should also allow an undo functionality that enables teams to retrace their steps and revert to an older version.

3. Test regularly and often

In the spirit of Agile, release fast and often and then test, test, test. And automate this as much as possible to avoid time-sucking bottlenecks between development, QA, and customer feedback.

4. Keep your releases small

It’s easier to test regularly if you keep your releases small. That way, if you need to make any revisions, they’ll be smaller, and your amends will have less of an impact on the other features. If you’re not used to releasing something that’s anything less than finished, then this can be a tricky mindset to adopt – but the more you do it, and the more you see the benefits of iterative feedback, the easier it’ll be.

5. Set up a review process

It’s easier to submit your work if you know there’s a safety net – i.e., someone else to check it before it goes to the customer. Many businesses use a hierarchical system for code review, which means junior developers have their work checked over by more experienced members of the team before it goes live. Having a pre-defined check system in place makes the whole process faster and more efficient.

Reviews and mentorship also don’t have to be strictly internal. Tools like Codementor for Teams can connect your junior team members with experienced mentors across all tech stacks for expert programming help and mentorship.

6. Keep the end-user in mind

Teams need to focus on the end-users at all times. Listen to feedback, and remember that if only the developers can use it, then there’s not much point in it existing.

The same goes for quality: try not to think of your product as something that just has to pass QA checks. Quality should be worked into every release. New features should be subject to automated tests to make sure code is bug-free, and planning for new features should include automated testing and performance monitoring.

7. Foster a culture of continuous improvement

The feedback loop is an essential part of continual delivery – and just because a product’s been delivered to the customer, it doesn’t mean your continuous improvement cycle is over.

Utilize tools that measure performance, revenue, engagement, and other metrics that can indicate how successful your product is. You can then track this information on the cloud, and use it to guide future iterations.

8. Make collaboration a way of life

It’s best when teams see their input as part of a larger picture – and they understand that just because their specific job is ‘done,’ it doesn’t mean their work is over.

Everyone should focus on making sure the product meets the end user’s needs. Developers should plan for production releases, QA teams should apply the same effort to every single release as they would do to a final finished product, and project managers should plan work with quality in mind.

Excellent organizational communication is a must. Having the right tools for the job is also half the battle.

Project management software can be a big help in this regard. Beyond helping managers and developers track their progress automatically, teams can access Kanban boards and progress charts to see both how their colleagues are doing, and where their work fits into the bigger plan.

Essentially, continuous delivery is all about collaboration, speed, and improvement – and the more tools you can use to help you achieve these three things, the faster and more efficient your project will be.

Want to learn more about the full software development lifecycle? Make sure to check out our DevOps Guide.