docker-tinynode

A small buildroot-based image for Docker, with NodeJS installed. It clocks in around 30MB.

The following useful modules/frameworks are installed:

• NodeJS version 0.10.30
• Express version 4.9.8
• CoffeeScript version 1.8.0
• Socket IO version 1.1.0
• Underscore.js version 1.7.0
• forever version 0.11.1

Currently using buildroot 2014.08

If you want to install different frameworks or specific versions, edit the tinynode_defconfig file, specifically the BR2_PACKAGE_NODEJS_MODULES_ADDITIONAL parameter. Everything there just gets passed to npm as-is, so you can specify things like forever@0.11.1 if you want that specific version.

What do I do with this?

It's pretty much up to you! I'm assuming you're already familiar with Docker -- if you aren't, I suggest you read up on the Docker documentation. https://docs.docker.com/userguide/

Here's a few ideas/pointers.

Bind-mount a volume with your script (easy)

So let's say your nodejs app is in a folder at /data/myapp - replace that with wherever your actual script is. And let's say your script is named app.js, and I'm going to assume your script is running something on port 8080.

You can mount the app's folder into the container with the -v parameter. You can place it anywhere you want, but the image is using /home/default as its working directory, so I recommend placing it somewhere in there.

The image's ENTRYPOINT parameter is forever - meaning when you start a container, anything you write out after the image name will be passed to forever. So at the minimum, you'll need the path to the script you want to run, but you can also pass options to forever - they're all listed in forever's readme

The one action you do not want to pass to forever is start - that causes forever to fork and detach and run as a daemon. Docker expects programs to not do that, so the container will just immediately exit if you use start

So putting it all together, you can run a command line:

docker run -p 8080:8080 -v /data/myapp:/home/default/myapp jprjr/tinynode myapp/app.js

• The -p 8080:8080 means to connect your host machine's port 8080 to the container port 8080.
• the -v /data/myapp:/home/default/myapp will mount /data/myapp (on your host) to /home/default/myapp (in the container)
• jprjr/tinynode is the name of the image
• myapp/app.js is the argument you're passing to forever - since the image's working directory is /home/default you can use a relative path.

If you need more ports, you can just add more -p arguments, and if you need to mount more folders, just add more -v arguments, etc. You could replace myapp/app.js with -w myapp/app.js and forever will autoreload the script when the file changes.

Build a new image from this one (less easy)

Just create a Dockerfile and begin with

FROM jprjr/tinynode

And do whatever you want. Your image will inherit a few things by default, like the ENTRYPOINT, WORKDIR, and USER parameters. Then in your Dockerfile, you can use commands like ADD to place your script into your new image, but then you'd have to rebuild the image anytime you update/change your app. This is why I recommend mounting a volume instead.

You can overwrite any of those parameters if you want, and you could add a CMD parameter if you want a default command to get passed to forever, etc.

Making your own stuff like this

This repo has a handy script for downloading buildroot and compiling the image, tinynode_build.sh

Here's the breakdown of what it's doing, so you can make similar images:

• Download + extract buildroot, and cd into it

• Copy "tinyfs_defconfig" from https://raw.githubusercontent.com/jprjr/docker-tinyfs/master/tinyfs_defconfig to the 'configs' folder inside your extracted buildroot folder.

• Run 'make tinyfs_defconfig' - this will setup a .config inside of buildroot with the bare minimum for compiling packages setup.

• If you want to create users, make a file named 'users' in that extracted buildroot folder with lines like:

  # syntax: username <uid> groupname <gid> <password> <home> <shell> <groups - optional> <comment - optional>
  default 1000 default 1000 ! /home/default -
  # ^ username default, uid 1000, group default, gid 1000, no password, homedir=/home/default, no shell
  john 1001 john 1001 changeme /home/john /bin/sh
  # ^ username john, uid 1001, group john, gid 1001, password "changeme", homedir=/home/john, shell=/bin/sh

• Run 'make menuconfig' - this will bring up an interactive menu for selecting packages, turning features on and off, etc

  • Generally speaking, you don't want to change the toolchain options, host options, etc, unless a package requires it (they'll tell you if that's the case)

• Once you're done, you can save your own defconfig by running make savedefconfig

  • The file will just be named defconfig, I recommend naming it projectname_defconfig under the configs folder.
  • This allows you to run make <projectname>_defconfig in the future.

• Once everything's setup, just type make - buildroot will download and setup cross-compilers, then build your packages.

• under output/images, you'll have a rootfs.tar file - this is your new filesystem!

• Copy rootfs.tar to some folder, and make a Dockerfile in that folder like:

  FROM scratch
  ADD rootfs.tar /