Serverless EU VAT Checker using REST

A simple AWS Lambda function using Java to check EU VAT numbers via HTTP GET.

Build

It is required to build prior to deploying. You can build the deployment artifact using Gradle or Maven.

Gradle

In order to build using Gradle simply run

$ gradle wrapper # to build the gradle wrapper jar
$ ./gradlew build # to build the application jar

The expected result should be similar to:

Starting a Gradle Daemon, 1 incompatible Daemon could not be reused, use --status for details
:compileJava
:processResources
:classes
:jar
:assemble
:buildZip
:compileTestJava UP-TO-DATE
:processTestResources UP-TO-DATE
:testClasses UP-TO-DATE
:test UP-TO-DATE
:check UP-TO-DATE
:build

BUILD SUCCESSFUL

Total time: 8.195 secs

Maven

In order to build using Maven simply run

$ mvn clean package

Deploy using Serverless

After having built the deployment artifact using Gradle or Maven as described above you can deploy the serverless method running the following commands:

# Install serverless globally
npm install serverless -g

Then, check the version to make sure you are using V1.16.0, or later:

$ serverless -v

Login to the serverless platform (optional)

$ sls login

$ sls deploy

The expected result should be similar to:

Serverless: Packaging service...
Serverless: Creating Stack...
Serverless: Checking Stack create progress...
.....
Serverless: Stack create finished...
Serverless: Uploading CloudFormation file to S3...
Serverless: Uploading artifacts...
Serverless: Updating Stack...
Serverless: Checking Stack update progress...
.................................
Serverless: Stack update finished...
Service Information
service: aws-java-maven
stage: dev
region: us-east-1
api keys:
  None
endpoints:
  GET - https://XXXXXXX.execute-api.us-east-1.amazonaws.com/dev/vatNumber/isValid
functions:
  vatChecker: aws-java-maven-dev-vatChecker

More details on Serverless @ https://serverless.com/framework/docs/getting-started/

Usage

You can now invoke the Lambda function directly and even see the resulting log via

$ serverless invoke --function vatChecker --log

The expected result should be similar to:

{
    "statusCode": 400,
    "body": "{\"error\":\"Missing query string parameters {number} and {country}. The parameter {country} holds a two character EU country code, for example BE. And {number} holds the VAT number you want to validate.\"",
    "headers": {
        "X-Powered-By": "Stephan Janssen (sja@devoxx.com) AWS EU VAT Lambda",
        "Content-Type": "application/json"
    },
    "isBase64Encoded": false
}
--------------------------------------------------------------------
START RequestId: XXXXXXXXX Version: $LATEST
2017-04-27 14:09:25 <XXXXXXXXX> INFO  com.serverless.Handler:29 - received: {}
END RequestId: XXXXXXXXX
REPORT RequestId: XXXXXXXXX	Duration: 165.92 ms	Billed Duration: 200 ms 	Memory Size: 1024 MB	Max Memory Used: 48 MB

Finally you can send an HTTP request directly to the endpoint using a tool like curl

$ curl -X GET 'https://XXXXXXX.execute-api.us-east-1.amazonaws.com/dev/vatNumber/isValid?country=IE&number=63388047V'

The expected result should be similar to:

 {
"isValid": true,
"name": "GOOGLE IRELAND LIMITED",
"address": "3RD FLOOR ,GORDON HOUSE ,BARROW STREET ,DUBLIN 4"
}

Function timouts

Some VAT checks can take between 6 and 10 seconds. This means the default Lamba function timeout of 6 seconds should be increated to 10 seconds.