Why? 🤷

Deploying Lambda functions manually involves quite a few steps.
Manually clicking buttons to upload zip files is fine the first few times but gets old pretty quickly.
There is an easier way!

What? 💭

Simplify the process of deploying a AWS Lambda Function without having to adopt a build tool/system.

How? ✅

There are 5 Steps to setup deployment for your Lambda Function:

1. install the dpl package from NPM 📦

npm install dpl --save-dev

2. Ensure that the required AWS Environment Variables are set: 🔐

In order to use dpl to deploy your Lambda function, you need to have a few environment variables defined. e.g: AWS_REGION and AWS_IAM_ROLE.

We have created a .env_sample file that shows you exactly which environment variables you need.

Simply copy it into your project. e.g:

cp node_modules/dpl/.env_sample .env && echo ".env\n" >> .gitignore

And then update the values with the real ones for your project.

Note: You need to have your AWS Credentials set to use the aws-sdk
if you have not yet done this, see below for instructions.

3. Add the list of files_to_deploy entry to your package.json 📝

In your package.json file, add the list of files & directories you want to be included in this zip that gets uploaded to AWS.

Example:

"files_to_deploy": [ "package.json", "index.js", "lib/" ]

Sample: package.json#L14-L17

4. Add a deployment script to the scripts section in package.json 📜

Example:

"scripts": {
    "deploy": "dpl"
}

5. Use the script to Deploy! 🚀

npm run deploy

Congratulations your Lambda Function is Deployed! 🎉

Troubleshooting 🙅‍

If you see an error message in your console, read the message and resolve it by correcting your setup. you have either not set your AWS Credentials or not defined the required environment variables. If you get stuck or have questions, ping us!

Implementation Detail 👷‍

Required Environment Variables 🔐

Deploying your Lambda function requires a few Environment Variables to be set.

AWS Credentials 🕸

As with all node.js code which uses the aws-sdk, it expects to have your AWS credentials stored locally. Your credentials are expected to be at: ~/.aws/credentials (e.g: if your username is alex, your AWS credentials will be stored at /Users/alex/.aws/credentials) If you have not yet set your AWS credentials on your machine do this now. Read about the AWS credential format.

AWS_IAM_ROLE

The script needs to know which AWS_IAM_ROLE you want to use to deploy/run the function.

Example:

export AWS_IAM_ROLE=arn:aws:iam::123456789:role/LambdaExecRole

AWS_REGION (where your lambda function will be deployed)

Example:

export AWS_REGION=eu-west-1

Optionally you can define a TMPDIR Environment Variable

To make the deployment script's run faster, and avoid forcing people to add entries into their .gitignore file, we store the /dist directory and resulting .zip file in your OS's Temporary storage.

e.g:

export TMPDIR=/path/to/where/you/want/dist/

Two things to add to your package.json

For the deploy scrip to do its job, we need to add two lines to our package.json

List of files_to_deploy

In your package.json file, add the list of files & directories you want to be included in your distribution.

Example:

"files_to_deploy": [ "package.json", "index.js", "lib/", ".env" ]

This tells dpl to copy these files and directory (with all contents) to the /dist which will be zipped and sent to AWS.

Check our package.json#L14-L17 file if in doubt.

Explanation of the Steps 👩‍🏫

dpl ("Deploy Lambda") performs the following 5 tasks

1. Create the /dist (distribution) directory 📁

Instead of uploading all the files in a project to S3/Lambda we upload only the required files. e.g: /src or /lib and ./index.js. While we are preparing this package, these required files are copied to the (temporary) /dist directory which will be zipped in Step 5.

Why a temporary directory? see: http://stackoverflow.com/questions/17946360/what-are-the-benefits-of-using-the-official-temp-directory-for-the-os

2. Copy required files into /dist directory ☕️

This typically includes the following:

• lib/ - the directory containing custom code your lambda function uses.
• package.json - the "manifest" file for your project, includes the Lambda function name, any configuration and dependencies.
• index.js - the "main" handler of your Lambda function.

3. Install (only production) node_modules in /dist directory 📥

We only need the "production" dependencies to be zipped and shipped. so instead of copying all the devDependencies in node_modules, we simply install a fresh set using the --production flag.

4. Zip the contents of the /dist folder to {function_name}.zip 📦

Once the /dist directory has been created with the necessary files and the dependencies have been installed in /dist/node_modules we zip the "distribution" ready for uploading to AWS.

This can take a few seconds depending on how many dependencies your Lambda function has.

5. Upload 🚀

Once the zip has been packaged we upload it to AWS using the aws-sdk. Your Lambda function will be named according to the "name" in the package.json file for your project.

Note: We are using the latest stable version of Node.js when deploying packages. see: https://aws.amazon.com/blogs/compute/node-js-4-3-2-runtime-now-available-on-lambda/
If for any reason you prefer/need to use the "Old" (legacy) version, please let us know: https://github.com/dwyl/aws-lambda-deploy/issues/33

Advantages of using dpl to deploy your Lambdas 💡

• Minial Dependencies - Our solution to the deployment task uses only one core dependency: the aws-sdk.

• Small Code - The entire dpl ("Deploy Lambda") module is fewer lines than our original
  gulpfile.js and uses only node.js core modules (you know and love) and your OS-native zip command.

• A beginner can read and understand all the code used in dpl in a few minutes; our code has both JavaDoc and in-line comments and we are here to help if you have any questions!

• No assumptions about your code style. e.g if you need any custom processing simply add a task in your scripts section of your package.json and run that task before deploying.

• No Global packages required or implied, just one dev Dependency.

 Optional configuration

Want to specify the MemorySize or Timeout settings for your Lambda function?

• "lambda_memory" - maximum memory allocation for your lambda function.
• "lambda_timeout" - maximum execution time.

In your package.json add:

"lambda_memory":"512",
"lambda_timeout": "30",

Environment Variables?

Unlike other AWS Lambda deployment methods, dpl lets you use environment variables in your Lambda Functions!

Simply add .env to your list of "files_to_deploy" in your package.json

Example:

"files_to_deploy": [ "package.json", "index.js", "lib/", ".env" ]

And an .env file will included in your .zip file that gets uploaded to AWS. This means you can use an Environment Variable loader e.g env2 in your Lambda function:

require('env2')('.env');

exports.handler = (event, context) => {
  if (event.hello === 'world') {
    return context.fail(JSON.stringify({
      statusCode: 500,
      message: 'sorry'
    }));
  } else {
    return context.succeed({
      statusCode: 200,
      message: process.env.HELLO  // or how ever you use environment variables!
    });
  }
};

Suggested Reading 👀

• Using NPM as a build tool: http://blog.keithcirkel.co.uk/how-to-use-npm-as-a-build-tool/ (you don't need gulp/grunt/etc...)