As Google currently allows coding only with JavaScript, we will be using Node.js throughout this book, with examples and demos. Google terms its serverless functions as Cloud Functions, so we will be using this term throughout this chapter. So, Cloud Functions are to be written in JavaScript and executed in Node.js v6.11.5 (at the time of writing this book) and the cloud function source must be exported in a Node.js module. The module will be loaded using a require() call. So, functions are contained within an index.js file. We can invoke the function from HTTP request methods such as GET, POST, PUT, OPTIONS, and DELETE. The deployment can be done through a command-line tool provided by Google Cloud CLI, through the cloud function UI on a GCP console, and can also be done through a serverless framework. We will be looking into each way throughout this chapter. The deployable is a ZIP file, which has functions packaged into it, and it is deployed on the Google Cloud storage bucket. Functions source code can be directly put into Cloud Functions as well, or we can reference it by uploading to the Google Cloud storage bucket. Let's look at various way to deploy function and further automate it through the Jenkins pipeline.