images

README

ContainerSSH Container Image Repository

This repository contains the scripts that build the ContainerSSH container images.

⚠⚠⚠ Warning: This is a developer repository. ⚠⚠⚠
The user documentation for ContainerSSH is located at containerssh.io.

How this repository works

This repository contains a build script in Go called build.go. It can be invoked by running go run build.go. This script will read build.yaml and build the container image based on that revision. It uses the GitHub API to download release artifacts, so it may need the GITHUB_TOKEN environment variable set. The optional --push flag can be set to push the images to the corresponding registries.

Under the hood the build uses docker-compose to build, test, and push the images. The build steps can be performed manually.

Before you begin you must set several environment variables. These are the following:

Variable	Required	Description
CONTAINERSSH_VERSION	Yes	Sets the ContainerSSH version to download.
CONTAINERSSH_TAG_VERSION	Yes	Sets the container image tag suffix to create. (See the Versioning section below.)
REGISTRY	No	Sets the registry prefix to push to. For example, quay.io/. Defaults to the Docker hub.
GITHUB_TOKEN	No	Sets the GitHub access token to work around anonymous rate limits.
SOURCE_REPO	No	Sets the source URL for downloads. Defaults to https://github.com/ContainerSSH/ContainerSSH.

For example, on Linux/MacOS:

CONTAINERSSH_VERSION="0.3.1"
CONTAINERSSH_TAG="0.3.1"

On Windows/PowerShell:

$env:CONTAINERSSH_VERSION="0.3.1"
$env:CONTAINERSSH_TAG="0.3.1"

Build

The build step requires build arguments to function. At the very least it should contain the CONTAINERSSH_VERSION variable so that the build knows which ContainerSSH release to download.

Optionally, you can also specify a GITHUB_TOKEN to work around GitHub rate limits and SOURCE_REPO to point the build to a different source URL.

docker-compose build

Test

Testing is done via a container called sut. This container will wait for ContainerSSH to come up and then run a simple SSH connection to it to test that it works correctly. This is not a comprehensive test, but checks if the image build was successful.

docker-compose up --abort-on-container-exit --exit-code-from=sut

Clean up after test

docker-compose down

Push

Finally, pushing container images can also be done from docker-compose. After a docker login command this can be simply done using the following command:

docker-compose push

Versioning

ContainerSSH container images are versioned independently of ContainerSSH. This allows for more frequent rebuilds of the image than we have ContainerSSH releases. This is important because we want our users to have frequent security updates. Therefore, the build script creates multiple tags for the image.

Let's take version 0.4.0, for example. Let's say the build.yaml contains the following configuration:

revision: 20200318
versions:
  0.4.0:
   - latest
   - 0.4
   - 0.4.0

In this case the build script would create the following tags:

• latest
• 0.4
• 0.4-20200318
• 0.4.0
• 0.4.0-20200318

Users can safely rely on the tag with the ContainerSSH version, or can specify a very specific build version should they need to pin to an immutable version.