An AWS lambda function that sends you an SMS (using Twilio) with today exchange rate for a give currency pair
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README.md

lambda-currency-exchange-sms

This a simple AWS lambda written in Node.js (>= 6.10) that allows you to monitor the exchange rate of a given currency pair and get an SMS every day (through Twilio APIs).

Sample message received every day (Today you get 1.12 EUR for 1 GBP)

Requirements

In order to test and deploy this lambda you will need to have:

  • An AWS account (and a user created in it)
  • the last version of AWS CLI tool installed and configured to use your AWS account
  • Node.js (version >= 6.10) and NPM installed in your machine
  • Lambda-local package installed globally in your machine (optional, only for local testing)
  • A Twilio account, an Api Key and a source phone number for SMS (free plan should be enough)

Configuration

Before being able to test and deploy this lambda you need to provided the needed configuration.

Configuration needs to be stored in a .env file (you can copy a template from the .env~SAMPLE sample file) that will look like this:

export BUCKET=your-unique-bucket-name
export STACK_NAME=currency-exchange-lambda
export CURRENCY_FROM="GBP"
export CURRENCY_TO="EUR"
export TWILIO_ACCOUNT="abcdefghijklmnopqrstuxywz123456789"
export TWILIO_API_KEY="1234567890abcdef1234567890abcdef"
export SEND_SMS_FROM="+3530123456789"
export SEND_SMS_TO="+3530234567890"

Where:

  • BUCKET: is the name of your S3 bucket that will contain the code to be deployed to AWS Lambda
  • STACK_NAME: the stack name for this project as it will appear in your cloudformation console
  • CURRENCY_FROM: The currency code from which you want to fetch the exchanges
  • CURRENCY_TO: The currency code to which you want to fetch the exchanges
  • TWILIO_ACCOUNT: Your Twilio account id
  • TWILIO_API_KEY: Your Twilio api key
  • SEND_SMS_FROM: Your Twilio source phone number
  • SEND_SMS_TO: Your destination phone number

Install dependencies

To install all the needed dependencies you simply need to run the following commands:

cd src
npm install

Local testing

With lambda-local installed and your shell in the root folder of this project, run:

source .env # will load the current configuration through env variables
lambda-local -l src/index.js -h handler -e event.json

Package and Deploy

Pre-requisites

Before being able to package and deploy the application you must have created an s3 bucket in your own account. You can do that with:

aws s3 mb "s3://your-unique-bucket-name"

Note: Your bucket needs to have a unique name, so you might need to spend sometime to find a unique one that works for you.

Once you have created your own bucket, be sure to update the BUCKET variable in your .env file

Package

The package process will generate a zip file containing the project source code all its dependencies and it will upload it on S3. The output of this operation will be a new cloudformation template (stored in .cloudformation) that can be used to deploy the application in your AWS account.

To package the application you can use the package script contained in this project:

./package.sh

Deploy

Once your app is packaged you are ready to deploy it on AWS with the deploy command:

./deploy.sh

License

Licensed under MIT License. © Luciano Mammino.

Contributing

Everyone is very welcome to contribute to this repository. Feel free to raise issues or to submit Pull Requests.