At DeliveryConf 2020, I facilitated a discussion about local development environments after Patrick Gray’s session Localdev And A Tight Feedback Loop.

I’ve participated in several discussions over the years. Why are local development environments so hard?

I have spent countless hours diagnosing various people’s environments. Then I had the epiphany: Treat localdev as you would production.

And what do I mean by that? Use the same tools that you are familiar with and use for production and apply that to local dev.

We use inspec to validate configuration on our production servers. For local dev, we need various things configured. Why not use inspec to verify required configuration.

For example, we want to pull gems from our artifactory instance instead of

control 'gemrc' do
  title 'Verify $HOME/.gemrc'

  path = "#{ENV['HOME']}/.gemrc"

  describe file(path) do
    it { should be_readable }

  describe yaml(path) do
    describe ':sources' do
      subject { YAML.load(file(path).content)[:sources] }
      it { should_not be_empty }
      it { should_not include(/ }
      it { should include(/ }

Now instead of a back and forth or slack, “What does your .gemrc file look like?” you can just have them run easily verify their environment with inspec.

$ inspec exec localdev.rb

Profile: tests from localdev.rb
Version: (not specified)
Target:  local://

  ✔  gemrc: Verify $HOME/.gemrc
     ✔  File /Users/joe.nuspl/.gemrc should be readable
     ✔  YAML /Users/joe.nuspl/.gemrc :sources should not be empty
     ✔  YAML /Users/joe.nuspl/.gemrc :sources should not include /
     ✔  YAML /Users/joe.nuspl/.gemrc :sources should include /

Profile Summary: 1 successful, 0 failures, 0 skipped
Test Summary: 4 successful, 0 failures, 0 skipped

At first, I was hesitant to use .gemrc as the example because :sources is a symbol key in .gemrc. inspec does not handle symbol keys so I had to override the subject of the block. In the end I thought others might has similar set ups so providing a working example for this corner case would be helpful.

As a chef shop, we have controls for .gemrc, bundler, Berkshelf, docker, and various other configurations. The controls grew organically. We started with a few things and whenever we encountered a new issue, we wrote a new control to verify a configuration. Actually, a lot of the tests are of the should_not variety. For example, certain versions of gems were known to be buggy so we verified those were not installed.

This work was inspired by the brew doctor command from Homebrew.

Stayed tuned for part two where we tackle the question: Are you running the latest version?