Deploy Deno to AWS Lambda

Description of video Jump to heading#

Show how to deploy Deno applications to AWS Lambda (using a community runtime for Lambda).

Transcript and code Jump to heading#

Run Deno on AWS Lambda Jump to heading#

Running Deno on AWS Lambda? Sure, you can do that. With AWS lambda the serverless pricing can be cheaper than a VPS and can be easier to maintain because it can auto scale behind the scenes.

To make that work, we’re going to use the aws-lambda-adapter project to make sure that our Deno.serve function runs as we expect it to. This is a popular approach to deploying to AWS lambda due to control, flexibility, and consistency.

There’s a nice article on this on the blog if you want to learn more about these considerations.

Let’s take a look at the Dockerfile that we can use to make this work:

# Set up the base image
FROM public.ecr.aws/awsguru/aws-lambda-adapter:0.8.4 AS aws-lambda-adapter
FROM denoland/deno:bin-2.0.2 AS deno_bin
FROM debian:bookworm-20230703-slim AS deno_runtime
COPY --from=aws-lambda-adapter /lambda-adapter /opt/extensions/lambda-adapter
COPY --from=deno_bin /deno /usr/local/bin/deno
ENV PORT=8000
EXPOSE 8000
RUN mkdir /var/deno_dir
ENV DENO_DIR=/var/deno_dir

# Copy the function code
WORKDIR "/var/task"
COPY . /var/task

# Warmup caches
RUN timeout 10s deno -A main.ts || [ $? -eq 124 ] || exit 1

CMD ["deno", "-A", "main.ts"]

Then we’ll build the Docker image.

docker build -t my-deno-project .

Now we need to start interfacing with AWS. If this is your first time working with AWS, you can create an account: https://aws.amazon.com

And if you haven’t installed the AWS CLI, you can do that too. You know if it’s installed by typing aws into your Terminal or Command Prompt. If that returns an error you can install with homebrew or follow the instructions through the website: https://docs.aws.amazon.com/cli/latest/userguide/getting-started-install.html

brew install awscli

Then you’ll want to make sure that you’re set up with aws configure. Everything that it is looking for is in the Security Credentials section of the AWS Console.

Use the CLI to create an ECR Jump to heading#

The ECR is a registry service where we can push our docker container

aws ecr create-repository --repository-name my-deno-project --region us-east-1 | grep repositoryUri

This outputs a URI for the repo: `"repositoryUri": "<<myuserid>>.dkr.ecr.us-west-1.amazonaws.com/my-deno-project",`

Then log in using the URI that comes back

aws ecr get-login-password --region us-east-1 | docker login --username AWS --password-stdin <username>.dkr.ecr.us-east-1.amazonaws.com/my-deno-project

Tag the image

docker tag my-deno-project:latest <myProject>.dkr.ecr.us-east-1.amazonaws.com/my-deno-project:latest

Then Push the image to ECR

docker push <myproject>.dkr.ecr.us-west-1.amazonaws.com/my-deno-project:latest

Now we need to create a function that will host our app:

• https://us-east-1.console.aws.amazon.com/lambda/home?region=us-east-1#/begin
• Think of a function as being a place where the app is going to run
• Select Create a Function
• Select Container Image Radio Button
• Call the function tree-app
• Select the app from the Browse Containers button
• Halfway down the page select “Configuration”
• Select Function URL
• Create a URL
• Select None so the endpoint is public
• Select Save
• Check the app in the browser

One thing to keep in mind with Lambda functions is cold start performance. Cold starts happen when AWS needs to initialize your function, and it can cause slight delays. There’s a pretty cool blog here that goes through Deno vs. other tools.

Using Deno with AWS Lambda functions is a great way to stand up your app quickly in a familiar environment.