dockerfiles

Repository contains multiple image projects. Image project can contain template files which will be used to generate resulting dockerfiles. For template automation procedures there are two scripts available:

• update.py - generates dockerfiles from given template files.
• publish.py - builds and publishes containers to a docker registry hub, such as https://registry.hub.docker.com or https://quay.io.

A short intro to templating

Let's start with dockerfiles layout first:

.
├── buildpack
│   ├── centos6
│   │   ├── curl
│   │   │   └── Dockerfile
│   │   ├── Dockerfile
│   │   └── scm
│   │       └── Dockerfile
│   ├── centos7
│   │   ├── curl
│   │   │   └── Dockerfile
│   │   ├── Dockerfile
│   │   └── scm
│   │       └── Dockerfile
│   ├── Dockerfile.template
│   ├── Dockerfile.template-curl
│   ├── Dockerfile.template-scm
│   ├── fedora21
│   │   ├── curl
│   │   │   └── Dockerfile
│   │   ├── Dockerfile
│   │   └── scm
│   │       └── Dockerfile
│   ├── fedora22
│   │   ├── curl
│   │   │   └── Dockerfile
│   │   ├── Dockerfile
│   │   └── scm
│   │       └── Dockerfile
│   └── suite.yml
├── dist.yml

Dockerfiles contains multiple image projects such as buildpack. Each project contains source templates supporting jinja2 templating.

Inside image project you need to create suites, update.py automatically populates each of the suites. Suite is basically a name reflecting distribution, version or maybe both. Going a level deeper we meet variants which correspond to the same suite but a different image project.

When you run update.py generation of the described hierarchy takes place. For example the script creates fedora21/Dockerfile, fedora21/scm/Dockerfile which correspond to buildpack:fedora21 and buildpack:fedora21-scm images. So as you can see generated images name represents the following pattern {{image}}:{{suite}}[-{{variant}}].

Configuration

dist.yml

Let's look at dist.yml, it contains patterns which map distribution names to suites.

fedora:
  - !regexp fedora([0-9.]+)
centos:
  - !regexp centos([0-9.]+)
ubuntu-debootstrap:
  - precise
  - trusty
debian:
  - wheezy
  - jessie

From the above example we can clearly see that debian has two suites: wheezy and jessie. Notable feature of this format is that it supports regex, so fedora distribution maps to suites described by regular expression. The first group match here makes particular sense it defines a version group. This is done because we say it generate fedora21 suite but the upstream image doesn't have such a tag, versioning however helps you to inherit from fedora:21.

suite.yml

Let's look at suite.yml of droneunit image project:

registry: quay.io/dennybaa/
variants:
  - upstart:
    - trusty
    - precise 
  - null
latest: trusty

The registry prefix sets registry prefix which means that when image is build (ex. droneunit) it will get name for example such as quay.io/dennybaa/droneunit:trusty.

Variants define what variants are available for particular suites, so for the upstart variant there are only two suites, but for the default variant Dockerfiles are generated for all of the suites. In other words when you don't expand variant as a list and all suites will be generated for this variant.

update.py and publish.py help

But first do pip -r requirements.txt.

update.py:

usage: update.py [-h] [image] [suite [suite ...]]

Generate Dockerfile(s) from suite template files.

positional arguments:
  image       Path to an image directory containing Dockerfile.template.
  suite       Specifies a list of suites to work on.

optional arguments:
  -h, --help  show this help message and exit

publish.py:

usage: publish.py [-h] [--rm] [--no-cache] [--no-push]
                  [image] [suite [suite ...]]

Generate Dockerfile(s) from suite template files.

positional arguments:
  image       Path to an image directory containing Dockerfile.template.
  suite       Specifies a list of suites to work on.

optional arguments:
  -h, --help  show this help message and exit
  --rm        Remove intermediate containers after a successful build.
  --no-cache  Do not use cache when building the image.
  --no-push   Do not use cache when building the image.