iPaaS@ORACLE.CLOUD: 2020

Introduction

From the Oracle website -

Oracle Cloud Functions is a serverless platform that lets developers create, run, and scale applications without managing any infrastructure. Functions integrate with Oracle Cloud Infrastructure, platform services and SaaS applications. Because Functions is based on the open source Fn Project, developers can create applications that can be easily ported to other cloud and on-premises environments. Code based on Functions typically runs for short durations, and customers pay only for the resources they use.

These Functions can be written in a variety of languages - Java, Python, Node etc. You write and deploy the code, Oracle takes care of provisioning, scaling etc.

Think of blocks of code that generally do one thing, e.g. applying a discount to an order. These are stored as Docker images in a docker registry. They can be executed via CLI or HTTP request. We will be using the latter in our example.

So how do Functions enhance the OIC experience?

Here's one use case - Say you are porting SOA Composites to OIC and you make use of Java Embedding in your BPEL process. Where shall I put that code in OIC?

Net, net - Functions can be leveraged to implement business logic that cannot be defined using the standard OIC actions. I realise that we do have the ability to upload Javascript libraries to OIC and then call the functions within, from an OIC process; however, that also has its limitations.

So let's implement a simple example -

Here is my Java class -

I realise the above is banal, but we can all extrapolate, correct?

Functions: creating an Application

Starting point is access to Oracle Functions -

Here I create an application - So what is an application?

Essentially a bucket for your functions e.g. HCM Functions, ERP Functions etc. It is also a unit at which resources can be allocated and configured. These resources can include subnet(s) allocated, whether logging is enabled etc.

Functions: creating a Function

I click on Getting Started

Launch Cloud Shell -

Note the initial setup cmds - you only need to do this once.

I do a fn list apps command and see my 3 apps, including oic-discount-app.

I now enter a cmd to create a Java function skeleton - fn init --runtime java oicdiscount-java

So what has been generated?

Let's look at the /src directory structure -

Let's look at main -

So here it has generated an example Hello World java -

I make a copy of this file, calling it OICDiscountFunction.java

I vi the result -

I can now delete the HelloWorld function -

So now I have my Java code defined, what about the other directory - /test?

As you can see, a tester class that invokes HelloWorld.

I could get remove the /test directory, but for the moment, let's amend to call our OICDiscountFunction. Same procedure- copy the existing Java file and amend as necessary.