Image Overview: node

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Minimal container image for running NodeJS apps

Download this Image

The image is available on cgr.dev:

docker pull cgr.dev/chainguard/node:latest

Compatibility Notes

The image specifies a default non-root node user (UID 65532), and a working directory at /app, owned by that node user, and accessible to all users.

It specifies NODE_PORT=3000 by default.

Node Application Example

This brief example is derived from our Getting Started with Node guide which is itself based on the Docker Node example. It involves setting up an example Node application, building the application into a container image using the Chainguard Node Image, and then testing the newly-built image.

Setting up an example application

You can set up our example Node application by cloning the node directory from our edu-images-demos repository.

git clone --sparse https://github.com/chainguard-dev/edu-images-demos.git

Because the Node demo application code is stored in a repository with other examples, we don’t need to pull down every file from this repository. For this reason, this command includes the --sparse option. This will initialize a sparse-checkout file, causing the working directory to contain only the files in the root of the repository until the sparse-checkout configuration is modified.

Navigate into the new directory.

cd edu-images-demos

To retrieve the files you need for this sample application, run the following git command.

git sparse-checkout set node

This modifies the sparse-checkout configuration initialized in the previous git clone command so that the checkout only consists of the repo’s node directory.

Navigate into the new node directory.

cd node/

From within this directory, run the following command to create a new package.json file:

npm init -y

Next, install the application dependencies. Specifically, you’ll need ronin-server and ronin-mocks. These will create a “mock” server that saves JSON data in memory and returns it in subsequent GET requests to the same endpoint.

npm install ronin-server ronin-mocks

Building the application image

After setting up the application, it can be built into a container image using the Dockerfile included in the example repository.

This Dockerfile will perform the following actions:

1. Start a new image based on the cgr.dev/chainguard/node:latest image;
2. Set the work dir to /app inside the container;
3. Copy application files from the current directory to the /app location in the container;
4. Run npm install to install production-only dependencies;
5. Set up additional arguments to the default entrypoint (node), specifying which script to run.

Build the application image with the following command:

docker build . -t wolfi-node-server

Testing the application

Once the build is finished, run the image:

docker run --rm -it -p 8000:8000 wolfi-node-server

Although the application is running from within a container, this command will cause it to block your terminal we set up a port redirect to receive requests on localhost:8000 as the application waits for connections on port 8000.

From a new terminal window, run the following command. This will make a POST request to your application sending a JSON payload:

curl --request POST \
  --url http://localhost:8000/test \
  --header 'content-type: application/json' \
  --data '{"msg": "testing node wolfi image" }'

If the connection is successful, you will receive output like this in the terminal where the application is running:

2023-02-07T15:48:54:2450  INFO: POST /test

You can now query the same endpoint to receive the data that was stored in memory when you run the previous command:

curl http://localhost:8000/test

{"code":"success","meta":{"total":1,"count":1},"payload":[{"msg":"testing node wolfi image","id":"6011f987-b9f8-4442-8253-d54166df5966","createDate":"2023-02-07T15:57:23.520Z"}]}

When you’re finished, you can close the application by pressing CTRL+C (CMD+C if you’re using macOS).