Application configuration and initialization are tangential to delivering business value, yet we frequently get bogged down by their incidental complexity. They crosscut various (Dev/QA/Prod etc.) environments and impact the workflow in subtle, disparate ways. In this session, I will discuss the experience of tackling this beast for several projects in a large team using an elegant functional programming approach. The approach was turned into a data-driven Clojure framework for applications to use. This success story is over two years old in production and it scales from a junior developer looking to learn the ropes to experienced folks focusing on advanced use cases. I will discuss the fundamentals of this approach, how it is used in production, in QA, and in development. I will also share the REPL-enabled development workflow and how it facilitates automated unit and integration testing.

Homoiconicity (code as data, data as code) is one of the hallmarks of Lisp. Clojure, a Lisp-1 language, has this wonderful feature too. In this talk I will discuss about performance optimization techniques that leverage homoiconicity.

No discussion on performance optimization can happen without discussing performance benchmarking. In this talk I will show how to do comparative benchmarking while trying to find performance bottlenecks. I will then proceed to showing techniques on using Clojure's homoiconicity to optimize performance. I will also show how to discover latency breakup of any Clojure code in a waterfall-chart model using homoiconicity.

Dependency inversion is an architectural cornerstone of well implemented Clojure applications. However, many Clojure applications start out with an ad-hoc, poorly abstracted initialization model - since application initialization needs to include dependency inversion in most cases, the latter is often omitted or not given the due attention it deserves.

Not treating dependency inversion as a first class concern has devastating consequences on testability (hence robustness), comprehension and maintainability of code, and causes a vicious circle of broken-windows effect.

In this talk I will go into the details of why and how such things happen, and how one can avoid those. I will discuss dependency injection as a flavour of dependency inversion and as a practical solution to achieve cleaner application design. I will illustrate the use of dependency injection mechanism through code examples and will share my experience of using the mechanism in real world projects.

This talk is about our experience of using Clojure in production at Concur for building a SaaS platform.

To set the perspective, Concur is a 22 years old, USD 8.3 billion enterprise, now a part of SAP. More than 70% of Fortune 500 companies use Concur for travel and expense solutions. Concur's SaaS platform serves 25,000 customers with 25 million users. The Concur SaaS platform was reaching its limits and needed "re-architecting". This talk is about why we chose Clojure at Concur and how we are building one of the world's largest B2B SaaS platforms in Clojure.

We will discuss the practices we established, experiments we did and the lessons learnt. We have now built a platform that follows open standards, is rigorously tested, tolerates failure and performs well. We will go over how we reached there, how we deployed the code to production and how we monitor those today.

If you are considering using Clojure in production or even simply interested in Clojure, you may get useful insights to take away from this talk.