Summary

Docker image for go development with SSH server. This image is the golang official plus a SSH server that let us connect to the container and build projects. The codes of your projects are stored in a volume.

As the image is for development purpose, git is installed and usable. The git email address and name recorded in any commits could be given in environment variables when running the image. The git (ssh) key with it passphrase and hosts where are located remote repositories could also be given in environment variables.

Build the image

To create this image, execute the following command in the docker-golang-dev folder.

docker build \
    -t cburki/golang-dev \
    .

Configure the image

The following environment variables could be used to configure the users.

• SSH_PASSWORD : The password for root and given user. No password is set when not specified.
• SSH_AUTHORIZED_KEY : Your public key that will be added to the authorized key file of the root and given user.
• SSH_USER : An optional user that will be created.
• GIT_EMAIL : The git email address recorded in any commits.
• GIT_NAME : The git name recorded in any commits.
• GIT_KEY_PASSPHRASE : The passphrase to protect the git key. A passphrase will be created for you if none is given.
• GIT_HOSTS : The list of git hosts to connect to (user1@host1:port1,user2@host2:port2,...).

You will not be able to log into this container if you do not provide at least SSH_PASSWORD or SSH_AUTHORIZED_KEY. Be careful to set a strong password for the users because they have full access to the volumes you specify to mount when running the container. When the user SSH_USER is created, the SSH_PASSWORD and SSH_AUTHORIZED_KEY are also set for this user. If no SSH_PASSWORD is given when creating the user, a password will be created for you. The new password is written to the logs during the first startup.

If you do not want to use git simply do not fill the GIT_* variables. Otherwise you need to fill them appropriately. If the use SSH_USER is created, the git settings are pushed for this user too. Be careful to set a strong passphrase for the git key because the key is used to push onto the remote repositories. The generated key must be added into your repositories settings (github or gitlab). To get the key you could execute the following command when the image is running.

docker exec \
    -i \
	-t \
	golang-dev \
	/bin/cat /root/.ssh/id_rsa-git.pub

Run the image

To access the SSH server you need to bind the port 22. The directory where your projects files reside could be mounted as a data volume.

docker run \
    --name golang-dev \
    -v <projects folder>:/data \
    -e SSH_PASSWORD=<your secret password> \
    -e SSH_AUTHORIZED_KEY=<your ssh public key> \
	-e GIT_EMAIL="<your git email address> \
	-e GIT_NAME="<your git name> \
	-e GIT_KEY_PASSPHRASE=<your secret passphrase> \
	-e GIT_HOSTS=user@host:port \
    -p <external port>:22 \
	-d \
    cburki/golang-dev:latest

When I'm not developping on my laptop, my development container is running on a server and I'm using a data volume container where my codes are synchronized with Google Drive using Insync (see cburki/insync image). You could also run your development container and attach a data volume container where your codes are stored.

docker run \
    --name golang-dev \
    --volumes-from golang-dev-data \
    -e SSH_PASSWORD=<your secret password> \
    -e SSH_AUTHORIZED_KEY=<your ssh public key> \
	-e GIT_EMAIL="<your git email address> \
	-e GIT_NAME="<your git name> \
	-e GIT_KEY_PASSPHRASE=<your secret passphrase> \
	-e GIT_HOSTS=user@host:port \
    -p <external port>:22 \
	-d \
    cburki/golang-dev:latest

Note that any other synchronization technology like dropbox, bittorrent sync, etc can be used to synchronize your project files. Just embed your synchronization tools in another container and attach the data volume container.