In this chapter, we will look at the runtime environment that is offered by Google App Engine. Overall, a few details of the runtime environment pertaining to the infrastructure remain the same no matter which runtime environment—Java, Python, Go, or PHP—you opt for.

From all the available runtimes, Python is the most mature one. Therefore, in order to master Google App Engine, we will focus on Python alone. Many of the details vary a bit, but in general, runtimes have a commonality. Having said that, the other runtimes are catching up as well and all of them (including Java, PHP, and Go) are out of their respective beta stages.

Understanding the runtime environment will help you have a better grasp of the environment in which your code executes and you might be able to tweak code in accordance and understand why things behave the way they behave.

In this chapter, we will cover the following topics: