(c) Cleuton Sampaio 2018

GO LAMBDA!

FaaS or Function as a Service is a way to expose a service function without the complexity of dealing with servers, platforms. and protocols. In fact, I have a dedicated blog about it: faas.guru.

If we want to expose a business function using standard technologies such as: REST, gRPC or even [Services Choreography] (https://github.com/cleuton/servicechoreography ), we’ll have a lot of boilerplate code in our project, ie: accidental complexity. This code does not add value to the function, but it is not harmless! It can generate big losses!

FaaS or Serverless is an alternative to focusing on what really matters, and that will bring us profit, leaving the infrastructure entirely to the cloud provider.

AWS Lambda

The AWS lambda service allows us to create code in various languages ​​(Java, Python, javascript, Go etc) and get on the platform without to worry about the infrastructure part.

Let’s create a very simple example, actually based on AWS’s own example. See the source file:

package main

import (
	"fmt"
	"context"
	"github.com/aws/aws-lambda-go/lambda"
)

type MyEvent struct {
	Name string `json:"name"`
}

func HandleRequest(ctx context.Context, name MyEvent) (string, error) {
	return fmt.Sprintf("Hello %s!", name.Name ), nil
}

func main() {
	lambda.Start(HandleRequest)
}

The code initiates a HandleRequest() function that simply gets a struct containing a JSON string. It just returns a greeting. But you could do anything, for example: Access a DynamoDB database for example.

Compiling

First, you need to install the aws-lambda-go package:

go get github.com/aws/aws-lambda-go/lambda

Then you must compile the project:

GOOS=linux go build awshello.go

Finally, you need to create a ZIP with your project. The ZIP name must be the name of the generated executable (in our case “awshello”):

zip function.zip awshello

Exporting

To deploy the package, you have two options: use AWS CLI or AWS Console. Unless you are using some kind of Continuous Delivery, the Console is simpler. Access the console and search for AWS Lambda service. Create a function using Runtime Go:

Then upload the zip file:

And configure a new JSON test event:

Now, just test your function:

You can then configure an AWS Services Event to trigger your function, or you can create a route using the AWS API Gateway.