Install-path based install context detection

Signed-off-by: Clinton Wolfe <clintoncwolfe@gmail.com>

lib/inspec/globals.rb

@@ -1,9 +1,15 @@
+require_relative "utils/install_context"
+
 module Inspec
+
+  extend Inspec::InstallContextHelpers
+
   def self.config_dir
     ENV["INSPEC_CONFIG_DIR"] ? ENV["INSPEC_CONFIG_DIR"] : File.join(Dir.home, ".inspec")
   end
 
   def self.src_root
-    File.expand_path(File.join(__FILE__, "..", "..", ".."))
+    @src_root ||= File.expand_path(File.join(__FILE__, "..", "..", ".."))
   end
+
 end

lib/inspec/utils/install_context.rb

@@ -0,0 +1,55 @@
+module Inspec
+
+  # Hueristics to determine how InSpec was installed.
+  module InstallContextHelpers
+
+    def guess_install_context
+      # These all work by simple path recognition
+      return "chef-workstation" if chef_workstation_install?
+      return "omnibus" if omnibus_install?
+      return "chefdk" if chefdk_install?
+      return "habitat" if habitat_install?
+
+      # Order matters here - gem mode is easily mistaken for one of the above
+      return "docker" if docker_install?
+      return "rubygem" if rubygem_install?
+
+      return "source" if source_install?
+
+      "unknown"
+    end
+
+    def chef_workstation_install?
+      !!(src_root.start_with?("/opt/chef-workstation") || src_root.start_with?("C:/opscode/chef-workstation"))
+    end
+
+    def chefdk_install?
+      !!(src_root.start_with?("/opt/chef-dk") || src_root.start_with?("C:/opscode/chef-dk"))
+    end
+
+    def docker_install?
+      # Our docker image is based on alpine. This could be easily fooled.
+      !!(rubygem_install? && File.exist?("/etc/alpine-release"))
+    end
+
+    def habitat_install?
+      !!src_root.match(%r{hab/pkgs/chef/inspec/\d+\.\d+\.\d+/\d{14}})
+    end
+
+    def omnibus_install?
+      !!(src_root.start_with?("/opt/inspec") || src_root.start_with?("C:/opscode/inspec"))
+    end
+
+    def rubygem_install?
+      !!src_root.match(%r{gems/inspec-\d+\.\d+\.\d+})
+    end
+
+    def source_install?
+      # These are a couple of examples of dirs removed during packaging
+      %w{habitat test}.all? do |devdir|
+        Dir.exist?("#{src_root}/#{devdir}")
+      end
+    end
+
+  end
+end

test/unit/utils/install_context_test.rb

@@ -0,0 +1,86 @@
+require "helper"
+require "inspec/globals"
+require "inspec/utils/install_context"
+
+def check_install_contexts(test_expected_to_be_true, also_rubygem)
+  should_be_false = %w{chef-workstation chefdk docker
+                     habitat omnibus rubygem source}
+  should_be_false -= [test_expected_to_be_true]
+  should_be_false = should_be_false.map { |m| "#{m}_install?".tr("-", "_").to_sym }
+  should_be_false -= [:rubygem_install?] if also_rubygem
+  should_be_false.each { |m| expect(Inspec.method(m).call).must_equal false }
+
+  should_be_true   = ["#{test_expected_to_be_true}_install?".tr("-", "_").to_sym]
+  should_be_true  += [:rubygem_install?] if also_rubygem
+  should_be_true.each { |m| expect(Inspec.method(m).call).must_equal true }
+
+  expect(Inspec.guess_install_context).must_equal test_expected_to_be_true
+end
+
+describe Inspec::InstallContextHelpers do
+  describe "when it looks like a Docker installation" do
+    before do
+      Inspec.expects(:src_root).at_least_once.returns("/somewhere/gems/inspec-4.18.39")
+      File.expects(:exist?).at_least_once.with("/etc/alpine-release").returns(true)
+    end
+
+    it "should properly detect a Docker install" do
+      check_install_contexts("docker", true)
+    end
+  end
+
+  describe "when it looks like a Habitat installation" do
+    before do
+      Inspec.expects(:src_root).at_least_once.returns("/hab/pkgs/chef/inspec/4.18.61/20200121194907/lib/gems/inspec-4.18.61")
+    end
+
+    it "should properly detect a habitat install" do
+      check_install_contexts("habitat", true)
+    end
+  end
+
+  describe "when it looks like a gem installation" do
+    before do
+      Inspec.expects(:src_root).at_least_once.returns("/Users/alice/.rbenv/versions/2.6.5/lib/ruby/gems/2.6.0/gems/inspec-4.18.61")
+    end
+
+    it "should properly detect a rubygem install" do
+      check_install_contexts("rubygem", true)
+    end
+  end
+
+  describe "when it looks like a source installation" do
+    before do
+      fake_root = "/Users/alice/src/inspec"
+      Inspec.expects(:src_root).at_least_once.returns(fake_root)
+      Dir.expects(:exist?).with("#{fake_root}/habitat").at_least_once.returns(true)
+      Dir.expects(:exist?).with("#{fake_root}/test").at_least_once.returns(true)
+    end
+
+    it "should properly detect a source install" do
+      check_install_contexts("source", false)
+    end
+  end
+
+  {
+    "Windows" => "C:/opscode",
+    "Unix-like" => "/opt",
+  }.each do |os_name, inst_dir|
+    describe "when on #{os_name} machines" do
+      {
+        "chef-workstation" => "chef-workstation",
+        "chefdk" => "chef-dk",
+        "omnibus" => "inspec",
+      }.each do |inst_mode, inst_subdir|
+        describe "when it looks like a #{inst_mode} installation" do
+          before do
+            Inspec.expects(:src_root).at_least_once.returns("#{inst_dir}/#{inst_subdir}/embedded/lib/ruby/gems/2.6.0/gems/inspec-4.18.39")
+          end
+          it "should properly detect a #{os_name} #{inst_mode} install" do
+            check_install_contexts(inst_mode, true)
+          end
+        end
+      end
+    end
+  end
+end