Implementing a Go-Based Serverless Application on OpenFaaS

Table of Contents

  1. Introduction
  2. Prerequisites
  3. Setup
  4. Creating a Serverless Function
  5. Deploying the Function
  6. Testing the Serverless Application
  7. Conclusion

Introduction

In this tutorial, we will learn how to implement a serverless application using Go and OpenFaaS. Serverless architecture allows developers to focus on writing code without worrying about infrastructure management. OpenFaaS is an open-source framework for building serverless functions. By the end of this tutorial, you will be able to create a Go-based serverless function, deploy it using OpenFaaS, and test the functionality.

Prerequisites

Before starting this tutorial, you should have the following prerequisites:

  • Basic understanding of Go programming language
  • Docker installed on your system
  • OpenFaaS installed and configured

Setup

To begin, let’s set up the required development environment.

  1. Install Docker on your system by following the instructions provided on the official Docker website.

  2. Install OpenFaaS by following the official OpenFaaS installation guide.

  3. Once you have Docker and OpenFaaS installed, you can proceed to the next steps.

Creating a Serverless Function

In this section, we will create a simple Go-based serverless function.

  1. Create a new directory for your project: bash mkdir serverless-app cd serverless-app

  2. Create a new file called handler.go and open it in a text editor: bash touch handler.go

  3. Add the following code to the handler.go file: ```go package main

    import (
    "fmt"
    "net/http"
)

func Handle(w http.ResponseWriter, r *http.Request) {
    fmt.Fprint(w, "Hello, World!")
}

func main() {
    http.HandleFunc("/", Handle)
    http.ListenAndServe(":8080", nil)
}
```

The code above defines an HTTP handler function `Handle()` that writes "Hello, World!" as the response. The `main` function sets up a server to handle incoming requests on port 8080.

  4. Save the file and exit the text editor.

Deploying the Function

Now that we have created the serverless function, let’s deploy it using OpenFaaS.

  1. Build a Docker image for the serverless function: bash docker build -t serverless-app .

  2. Log in to your OpenFaaS gateway: bash faas-cli login --gateway=http://<your-openfaas-ip>:<port> 

    Replace `<your-openfaas-ip>` and `<port>` with the appropriate values for your OpenFaaS installation.

  3. Deploy the serverless function: bash faas-cli up -f ./handler.yml 

    Create a file called `handler.yml` in the project directory with the following contents:
```yml
version: 1.0
provider:
  name: faas
  gateway: http://<your-openfaas-ip>:<port>
functions:
  serverless-app:
    lang: dockerfile
    handler: ./handler
    image: serverless-app
```

Replace `<your-openfaas-ip>` and `<port>` with the appropriate values for your OpenFaaS installation.

  4. Wait for the deployment to finish. Once it’s done, you will see a message confirming the successful deployment of the function.

Testing the Serverless Application

Now that the serverless function is deployed, let’s test its functionality.

  1. Access the OpenFaaS portal by visiting http://<your-openfaas-ip>:<port> in your web browser.

  2. Click on the “Functions” tab and find your deployed function (serverless-app).

  3. Click on the function name to open its details page.

  4. Click on the “Invoke” button to test the function. You should see the response “Hello, World!”.

    Congratulations! You have successfully implemented a Go-based serverless application on OpenFaaS.

Conclusion

In this tutorial, we learned how to create a serverless function using Go and deploy it using OpenFaaS. We also tested the functionality of our serverless application. By following this tutorial, you gained hands-on experience with Go-based serverless development and OpenFaaS deployment. Now you can explore more complex serverless applications and leverage the power of Go’s concurrency features to build scalable and efficient systems.

Remember to clean up any resources you no longer need to avoid incurring unnecessary costs.

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