Gil Tayar: Being Agile

Meet Our Team — October 29, 2018

This interview originally appeared on the Blazemeter blog. We like it so much we’re cross-posting it here.

Blazemeter sat down recently to learn from Gil Tayar, who is both a senior software architect and an evangelist on the software engineering team at Applitools in Israel. He joined Applitools in 2017, and already has made some great contributions, having led the development of the ultrafast grid of hundreds of browsers on our cloud, enabling customers to capture screenshots of their application UIs on multiple types of browsers and screen resolutions, and find more bugs in less time.

Before Applitools, Gil started out in Mamram in the late ‘80s. He was a teacher at the Mamram School and taught PC courses like C, C++, Assembler, and Windows. Back then, PCs were so low-powered that the other developers laughed at him, telling him that he should leave the PC and come join them on “real” computers like the mainframes and the minicomputers. I told them to wait and see — PCs will conquer the world. And I was right!

This belief, that low-end computing would beat out high-end “upscale” environments, has led Gil’s thinking in all his career, and can be seen in his choice of the NodeJS platform, which people tend to think of as low-scale compared to “worthy” platforms such as the Java Virtual Machine. Well, just wait and see.

Besides working in various startups before and during the bubble of the late 90’s, Gil co-founded his own startup in the 2000s, which somehow managed to survive the collapse of 2001 and the one in 2008. After three years in Cloudshare, and three years at Wix, designing and building what is now known as Wix Code, Gil spent a year trying to build a software development bootcamp.

After that, he finally landed at Applitools, where he gave us this interview.

We sat down with Gil to learn more about him, his work style, and his career.

Software Development Habits

Hi Gil! You have ~30 of experience in startups and in high tech, so you have a really good perspective on development and deployment processes. Tell me, what is your company’s development and testing “flow”?

Each team is pretty independent, which is as it should be in an agile environment! First of all, and probably most important of all, we do not differentiate between development and testing. Testing, for us, is a part of development.

I checked a while back the percentage of development vs testing code, and found a 60-40 ratio between them, i.e. we write more test code than application code. (Do we do TDD? Well, no. We don’t care how you write your tests, as long as you do. It’s OK to do TDD, but it’s not obligatory.)

Why do we concentrate on that? In one word: fearlessness. We need to stop fear from entering into the development cycle. Fear of deployment and fear of refactoring are the #1 inhibitors to agile development. And the only cure for that fear is testing. Testing your code (non-manually, of course) is the only way to enable you to write the code for a feature and deploying it at the same day, without fear. And testing is the only way to enable you to refactor pieces of your code and deploy it immediately without fear.

Microservices & Micro-deploys

It’s interesting that you associate release with fear. What else do you do?

The second most important principle is that we do not have releases, and we do not have feature branches (except for extreme cases). The trunk is always in a state that is ready for deployment, and it is deployed a few times a day. This does not mean that a developer hoards the code for a feature locally until that feature is ready. On the contrary, he writes the code for the feature piecemeal and pushes and deploys each piece, even if the feature is not yet ready.

Why is writing code in small increments so important?

Because this means that each deploy only contains a few changes and not big ones at that. Which means that there is less risk involved in deploying, and if that deploy breaks the system, less risk and time involved in rolling that change back.

After all, development is all about managing risk. Because there is always risk, even if you do testing. Small changes, deployed daily, mitigate risk.

Deploying a few times a day—that’s impressive! How does that reflect on sprints?

No sprints! Features are deployed as they come out of the development oven. We manage the backlog in a simple manner, assign features/bugs to a developer, and when they’re done, we deploy. We feel that this decreases the pressure felt by the developers at the end of the sprint to ensure that they “finish the features”. Yes, we still have timelines, which the developer should abide by, but it’s okay if it’s not on the day. (And, yes, sometimes we have those hard deadlines).

I wonder what developers think of that. Anything else we can learn from?

The third thing we do—which superficially is more of an architecture decision, rather than a process decision—is to use microservices. People tend to think of using microservices as something that is needed for projects that need large scale.

And while this is true, I believe that most other projects can benefit from this architecture. Why? Because it reflects a lot on the development process, and on the two principles above: testing and small changes deployed daily.

How are microservices connected to testing?

Microservices are, by definition, small in nature. And because they are small, they are easy to test. And making testing easy is critical in an environment that emphasizes testing as ours does. Finally, due to the fact that the unit of deployment is a small microservice, deploying a microservice, and rolling it back if necessary, is less of a deal than deploying a big monolithic application.

Gil Tayar, Sr. Architect and Evangelist @ Applitools

Blending Development & Testing

So heading back to the topic of developers and testing, you said that development is interconnected with testing. How does that affect the relations of developers and testers?

Our teams are built only of developers. They deal with all aspects of product development: from writing the code, writing and executing the tests, manual QA if that is needed, building the production infrastructure, writing the deployment scripts, and deploying to, maintaining and monitoring production.

There is no specialization: each team member is required to participate in all these aspects. And agility benefits too — it enables us to create features in a minimum amount of time, without being bound by the timelines and restrictions of other teams. If you don’t have QA, and you don’t need to throw your code over the wall to be tested, then you can write the feature in a day, and deploy it in the next.

And you can do that because you wrote the tests that ensure that everything is OK, and because your change is small enough that you can allow yourself to deploy it, and roll it back if something bad happens.

And if we need changes in production infrastructure? Well, we just implement them.

Toolchain Recommendations

Let’s talk a bit about the tools you use. Which tools do you recommend, and for what?

I am extremely satisfied with NodeJS and with Kubernetes, and the simplicity in which I can build a microservices infrastructure with both of them continues to astound me. As for the other tools, my guiding principle has always been to choose the simplest tool that can possibly work.

So, while I could have used, for example, JFrog Artifactory, to store both my npm packages and Docker images, using the standard npmjs registry and Docker Hub is simple and good enough for my purposes.

And while I could use Jenkins for all my building and deployment needs, a combination of CircleCI and deployment scripts I store in Git is much simpler and easier to maintain.

And Applitools Eyes, for visual testing, is obviously the best there is!

How to go Agile

What do you recommend to companies who are trying to go agile?

The first thing I recommend: don’t turn it into a “project”. It will take its time—probably a couple of years. So don’t rush it. Trying to make it happen faster just ensures that it won’t happen at all.

The second thing: make your teams product-oriented, and mostly independent from one another. This is the most difficult to do, especially in large companies, as the immediate response to that is, “we can’t do that because we’re a big company and we want control”.

But control is anathema to agility. Keep those teams independent! Let them choose their development and production environment, even if that means losing control.

The third thing: once that team is independent, insist on an automated CI/CD pipeline with no feature branches. They can develop that pipeline themselves (it’s easy to do today with all the tooling that exists), but it has to be there.

The fourth thing: developers should write their own tests and not rely on QA gating their code before deployment. This is because they should be deploying their code daily. Insist on that, otherwise your move to an agile development process will be a hollow one. Some people call this “Shift Left“.

Last but not least, please share a valuable lesson you learned.

  • Write the rollback script before the first rollback is needed, not during.
  • Logging everything in an orderly way is crucial. It enabled us to troubleshoot problems in production in a nice and simple way, without the need to use a debugger on production code.
  • Logging performance is crucial and enables you to figure out where your performance problems are without any of the newfangled distributed tracing tools.
  • Microservices’ benefits are also for non-internet-scale projects: testing and deployment benefit from them tremendously, regardless of their benefits for scaling.

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