The Nexus Docker Environment

I work as a developer for Nexus. One of the things I’ve done to make it easier for new developers to come on board and start contributing code was to create a Docker image that contains a pre-built development environment containing everything a new developer might need. It also helps with being able to reproduce each other’s bugs, as our environments are all very similar. I’ve been using it myself every day now for about a month, so I figured it’s time I write a post introducing it.

The image contains an installation of the Solidity compiler, the Go Ethereum client, Dapple, and a few other things. The Docker image is up on Docker Hub as ryepdx/nexus_dev, available for anyone to pull down. The Dockerfile itself, along with a README detailing the installation instructions, can be found on Github.

The image requires some configuration for enabling key-based SSH login and for setting up any Github SSH keys you might have. The configuration steps are outlined in detail in the README on Github. An abbreviated version of the installation instructions can also be found below. Note that it is assumed you already have an SSH key pair you can use for logging in to the Docker image. If you don’t, Atlassian has a guide to generating SSH keys that covers Windows, Linux, and OS X.

$ git clone https://github.com/NexusDevelopment/devenv-docker.git
$ cd devenv-docker
$ ./docker-run --name nexus ryepdx/nexus_dev
$ ifconfig

...
docker0 Link encap:Ethernet HWaddr 02:42:2A:19:B8:B2
 inet addr:172.17.42.1 Bcast:0.0.0.0 Mask:255.255.0.0
...

$ ftp 172.17.42.1 2121

Name: dev
Password:

230 OK. Current directory is /home/dev
Remote system type is UNIX.
Using binary mode to transfer files.

ftp> put ~/.ssh/docker.pub .ssh/authorized_keys
local: /home/ryepdx/.ssh/docker.pub remote: .ssh/authorized_keys
200 PORT command successful
150 Connecting to port 42773
226-File successfully transferred

ftp> put ~/.ssh/github.key .ssh/github.key
local: /home/ryepdx/.ssh/github.key remote: .ssh/github.key
200 PORT command successful
150 Connecting to port 42773
226-File successfully transferred

ftp> put ~/.ssh/github.pub .ssh/github.pub
local: /home/ryepdx/.ssh/github.pub remote: .ssh/github.pub
200 PORT command successful
150 Connecting to port 54191
226-File successfully transferred

ftp> bye
221 Goodbye.

$ ssh -i ~/.ssh/docker.key -p 2222 [email protected]

(nexus)[email protected]:~$ passwd
Changing password for dev.
(current) UNIX password: 
Enter new UNIX password: 
Retype new UNIX password: 
passwd: password updated successfully
(nexus)[email protected]:~$ chmod 400 ~/.ssh/*.key*

If you already have an Ethereum chain synced up on your host machine, you might also consider mounting the ~/.ethereum directory on your host machine to /home/dev/.ethereum in your Docker container using Dockers “-v” flag during the “./docker-run” step. This prevents duplication of data and saves you some hard drive space.

Once your Docker container is all configured, you can opt to write your code using an external IDE over FTP, or you can use the copy of vim included in the image. I personally use vim and keep all my vim configuration files on Github so all I have to do to get vim set up the way I like it is to just pull them down.

One of the really nice things about having my development environment in a Docker image has been the ease with which I can tear everything down and bring everything back up again. If I do something that borks my environment, I don’t have to spend a bunch of time debugging it. I can just delete my Docker container and start again. I’ve also successfully leveraged Unison and a Digital Ocean droplet running CoreOS to provide myself with a remote development environment that stays synchronized with my local environment. This allows me to SSH into my Digital Ocean server with my phone or a tablet to write some code or run some tests whenever the mood strikes me. It’s like using a cloud-based IDE, except I have more control over my experience and my data.

Hopefully you find this Docker image useful. If you have any questions or need help, get in contact with me and I’ll do what I can.