adamalex/docker-urlarchiver

Use Docker to package a Node.js script with all its dependencies, including Node.

This repo serves double-duty as:

1. An example of using Docker to package a Node.js script with all dependencies, including Node. I hope both that this is useful to someone and that I hear some suggestions for improvement from those more experienced with Docker.

2. If you happen to need to save a URL's response body to Amazon S3, a useful script that can be executed with Docker or directly with Node.

What is Docker?

If you're unfamiliar with Docker, please read The Whole Story if you have a few minutes. In short, it is a powerful new way to think about deploying software that decouples an application and its dependencies from the various types of environments where it may be deployed.

Example files

• app.js is a single-purpose Node.js script that takes its configuration from environment variables and saves the response from a configurable URL to a configurable place on Amazon S3. It knows nothing about Docker.

• Dockerfile allows you to bundle app.js with all Node.js dependencies and OS dependencies, including Node itself! With Docker, you can run this image even on a machine that doesn't have Node installed. The Dockerfile doesn't care what's happening inside app.js, so it serves as a basic example of using Docker to create an image that contains the desired version of Node to be used to execute a script.

Configuration

In case you are interested in the example logic that saves a URL's response to Amazon S3, the following environment variables are used for configuration:

• AWS_ACCESS_KEY Your IAM access key, for saving content to your S3 account. Familiarize yourself with the IAM Best Practices to limit your exposure when using these credentials.

• AWS_SECRET_KEY The secret associated with the above key

• S3_BUCKET The target S3 bucket

• S3_OBJECT The target filename

• TARGET_URL The URL from which to download the response that will be saved in the above S3 location

• SUCCESS_URL An optional URL to GET when the script completes successfully. This is great if you use a service like Dead Man's Snitch to alert you when your scheduled tasks stop working.

Usage

Run using Docker

As the primary use case, this is how you use Docker to run the example script. Note that the only dependency for this is Docker itself.

# Pull the preconfigured image to speed things up the first time you run
$ docker pull adamalex/urlarchiver

# Execute the example script within a Docker container
$ docker run \
  -e "AWS_ACCESS_KEY=..." \
  -e "AWS_SECRET_KEY=..." \
  -e "S3_BUCKET=..." \
  -e "S3_OBJECT=..." \
  -e "TARGET_URL=..." \
  -e "SUCCESS_URL=..." \
  adamalex/urlarchiver

Build a custom Docker image

Should you want to customize the Dockerfile or the script itself, or just feel safer using your own Docker image, you can follow the below instructions to build your own image.

# Build the image
$ docker build -t="yourname/imagename" .

# Run the image. The environment variables will of course be different
# if you have replaced the example script with your own logic.

$ docker run \
  -e "AWS_ACCESS_KEY=..." \
  -e "AWS_SECRET_KEY=..." \
  -e "S3_BUCKET=..." \
  -e "S3_OBJECT=..." \
  -e "TARGET_URL=..." \
  -e "SUCCESS_URL=..." \
  yourname/imagename

Run using Node.js

Although this example logic is not the primary focus of this repository, this is how you would run the script outside of Docker by using Node.js directly.

$ npm install
$ export AWS_ACCESS_KEY="..."
$ export AWS_SECRET_KEY="..."
$ export S3_BUCKET="..."
$ export S3_OBJECT="..."
$ export TARGET_URL="..."
$ export SUCCESS_URL="..."
$ node app.js

Next Steps

• Learn more about Docker
• Tweet at me or File an issue if you have questions or comments