Test Drive Your Dockerfiles with RSpec and ServerSpec

Dockerfile

FROM ubuntu:14.04
MAINTAINER Mason Fischer <mason@thoughtbot.com>
RUN apt-get update && apt-get install -y nodejs

Dockerfile_spec.rb

require "serverspec"
require "docker"

describe "Dockerfile" do
  image = Docker::Image.build_from_dir('.')

  set :os, family: :debian
  set :backend, :docker
  set :docker_image, image.id

  it "installs the right version of Ubuntu" do
    expect(os_version).to include("Ubuntu 14")
  end

  it "installs required packages" do
    expect(package("nodejs")).to be_installed
  end

  def os_version
    command("lsb_release -a").stdout
  end
end

yo Vamsi you want to take a look over at my comment here.

Basically, you've got a newer version of specinfra which has a 'fix' for Containers with nil CMD. What that fix is actually doing is replacing your Dockerfile CMD and misusing an shell expression. This blows up, you end up getting the wrong object returned which doesn't give you an object with #stdout.

I'd recommend just watching that issue and see what happens, in the meantime, downgrade your serverspec and specinfra.

Hi @dekz,

Thanks for your reply.Can you recommend me the version to use for serverspec and specinfra.it will be great help so that i can see if this sort issue occurs again in my env

Thanks,
Vamsi KGR

Hm. I'm getting this error:

Failures:

  1) Dockerfile installs required packages
     Failure/Error: expect(package('ruby')).to be_installed
       expected Package "ruby" to be installed

     # ./spec/Dockerfile_spec.rb:25:in `block (2 levels) in <top (required)>'

  2) Dockerfile Package "ruby" should be installed
     Failure/Error: it { should be_installed }
       expected Package "ruby" to be installed

     # ./spec/Dockerfile_spec.rb:29:in `block (3 levels) in <top (required)>'

Finished in 1.68 seconds (files took 0.28967 seconds to load)
3 examples, 2 failures

Which is weird because it really is installed.

arioch to be honest I haven't had a look at how the internal of serverspecs works with regards to checking packages installed. But since yours is up and running unlike Vamsi's then I'd suggest digging in a bit further.

Vamsi, try v2.15.0 of specinfra. v2.15.1 is the release is the buggy release. Or try applying my commit here.

I didn't have any success getting this to work using latest serverspec and specinfra 2.15.0, 2.15.1, 2.15.2, nor 2.16.0 does a full example "project" exist, where i could just go git clone ... and rake spec?

I wonder if the problem is their in my setup or with the above spec file 😔

Here is what some thing i get after the specinfra v2.15.0 installed

 1) Dockerfile installs the right version of Ubuntu
     Failure/Error: command("lsb_release -a").stdout
     NoMethodError:
       undefined method `stdout' for #<Docker::Container:0x00000002541b20>

Here are some of my machine details

root@vagrant:/vagrant# ruby -v
ruby 1.9.3p484 (2013-11-22 revision 43786) [x86_64-linux]
root@vagrant:/vagrant# docker version
Client version: 1.5.0
Client API version: 1.17
Go version (client): go1.4.1
Git commit (client): a8a31ef
OS/Arch (client): linux/amd64
Server version: 1.5.0
Server API version: 1.17
Go version (server): go1.4.1
Git commit (server): a8a31ef

root@vagrant:/vagrant# gem list

*** LOCAL GEMS ***

archive-tar-minitar (0.5.2)
bundle (0.0.1)
bundler (1.8.2)
diff-lcs (1.2.5)
docker-api (1.19.0)
excon (0.44.2)
json (1.8.2)
multi_json (1.10.1)
net-scp (1.2.1)
net-ssh (2.9.2)
rspec (3.2.0)
rspec-core (3.2.0)
rspec-expectations (3.2.0)
rspec-its (1.2.0)
rspec-mocks (3.2.0)
rspec-support (3.2.1)
serverspec (2.7.1)
specinfra (2.15.0)

Btw the commit is more specific to the CMD inside the Dockerfile to check or with the cmd to execute in the spec file?
This really halts my work so badly 😫 #dekz or @dekz need you help on this

@masonforest great blog post! Any suggestions on how to go about removing the images after the tests get run? I've tried it this way, but this doesn't seem right (or to work!)

https://github.com/tfhartmann/docker-puppetserver/blob/73935b2a3aaedca27e3c0984823912b565f39546/spec/Dockerfile_spec.rb#L14-L16

Just calling out: it's important to specify that you should use the docker-api gem. The docker gem is not the right one to use. But confusingly, the require statement is correct!
require "docker"

@cjcjameson you just saved me a lot of time buddy, thx. and thx @masonforest !

Oh my! The docker-api gem! what a difference that makes! @masonforest - do you think you can update the article to call this out? it would have saved me a bunch of time!

@tfhartmann : I add this to my specs:

after(:all) do
    @image.remove(:force => true)
end

In the example you build the image only. I assume ServerSpec is starting the container and stopping by the end of the test. How can you pass arguments to the container such as environment variables, commands, volumes, etc?

Hello, this is my version of docker:

$ docker -v                                                                     
Docker version 1.11.1

I can't using rspec and always getting this message:

$ bundle exec rspec spec                                             
No examples found.


Finished in 0.00098 seconds (files took 1.23 seconds to load)
0 examples, 0 failures

this is my directory structure:

$ tree .                                                                          ‹ruby-2.3.0›
.
├── Dockerfile
├── run
└── spec
    └── Dockerfile_spec.rb

1 directory, 3 files