gscho/webmock_cookbook

A Chef custom resource for mocking HTTP requests

webmock cookbook

This cookbook will enable the webmock resource in any cookbooks that depend on it.

What can you do with this cookbook?

This cookbook is a simple wrapper around the webmock gem. This gem allows you to mock any HTTP request and return a value for test purposes. Doing so allows you to decouple external HTTP services from testing the logic of your cookbook.

Use cases:

• testing a chef library helper that makes HTTP requests to an external service
• mocking responses from services that are not accessible locally

This cookbooks just gives you convenient access to the webmock gem. All webmock APIs are documented here: https://github.com/bblimke/webmock

How to use

This resource is meant for testing. That means you should only call these resources when testing a cookbook! If you're already using test kitchen, you could include this recipe when running test-kitchen tests or using an attribute.

# A webmock resource enables mocking of http requests from within a recipe

webmock 'registering a stub' do
  block               block
  allow_net_connect   true, false
  allow_localhost     true, false
  allowed_hosts       []
end

where:

- block is a block of ruby code to execute with the webmock api
- allow_net_connect is a boolean to allow outbound http requests
- allow_localhost disables outbound http requests except localhost
- allowed_hosts disables all outbound http requests except these hosts

Mocking for a chef resource

# Everything inside the block is using the webmock documentation
webmock 'stub example.com' do
  block do
    stub_request(:get, "http://example.com/index.html").
     with(
       headers: {
      'Accept'=>'*/*',
      'Accept-Encoding'=>'gzip;q=1.0,deflate;q=0.6,identity;q=0.3',
      'Host'=>'example.com',
      'User-Agent'=>'Chef Infra Client Knife/16.10.17 (ruby-2.7.2-p137; ohai-16.10.6; x86_64-linux; +https://chef.io)',
      'X-Chef-Version'=>'16.10.17'
       }).
      to_return(status: 200, body: "<h1>Hello World!</h1>", headers: {})
  end
  action :run
end

# This will be mocked
remote_file '/tmp/index.html' do
  source 'http://example.com/index.html'
end

Mocking for a chef library

The order is important! You must also make sure run_action(:run) is specified to make sure the resouce executes at compile time

# Everything inside the block is using the webmock documentation
webmock 'stub google.com' do
  block do
    stub_request(:get, "http://google.com/foo/bar").
      with(
        headers: {
        'Accept'=>'*/*',
        'Accept-Encoding'=>'gzip;q=1.0,deflate;q=0.6,identity;q=0.3',
        'User-Agent'=>'Ruby'
        }).
      to_return(status: 200, body: "It worked!", headers: {})
  end
  action :run
end.run_action(:run)

# This will be mocked
data = third_party_http_request "google.com", '/foo/bar'
file '/tmp/data.txt' do
  content data
end