Summary

In this chapter, we saw that it's good to have solid and reliable patterns to build software to be sure that we stand over the shoulder of tested decisions that we can use to shape new designs. For web services living in the cloud, we can use the Twelve-Factor App methodology as a guideline for a lot of useful advice.

We discussed how the Twelve-Factor App is aligned with two main ideas – CI and scalability.

CI is the practice of constantly validating any new code by running tests automatically after the code is shared. This creates a safety net that enables developers to move quickly, although it requires discipline to properly add automated tests as new features are being developed.

We also discussed the concept of scalability, or the capacity for software to allow more load by adding more resources. We talked about why it is important to allow the software to grow and reduce based on the load, even to the point to be able to adjust dynamically. We...