core: Vagrant.installer_embedded_dir

lib/vagrant/shared_helpers.rb

@@ -8,6 +8,15 @@ module Vagrant
   # @return [String]
   DEFAULT_SERVER_URL = "https://www.vagrantcloud.com"
 
+  # Returns the path to the embedded directory of the Vagrant installer,
+  # if there is one (if we're running in an installer).
+  #
+  # @return [String]
+  def self.installer_embedded_dir
+    return nil if !Vagrant.in_installer?
+    ENV["VAGRANT_INSTALLER_EMBEDDED_DIR"]
+  end
+
   # This returns whether or not 3rd party plugins should be loaded.
   #
   # @return [Boolean]

test/unit/vagrant/shared_helpers_test.rb

@@ -8,6 +8,21 @@ describe Vagrant do
 
   subject { described_class }
 
+  describe "#installer_embedded_dir" do
+    it "returns nil if not in an installer" do
+      Vagrant.stub(in_installer?: false)
+      expect(subject.installer_embedded_dir).to be_nil
+    end
+
+    it "returns the set directory" do
+      Vagrant.stub(in_installer?: true)
+
+      with_temp_env("VAGRANT_INSTALLER_EMBEDDED_DIR" => "/foo") do
+        expect(subject.installer_embedded_dir).to eq("/foo")
+      end
+    end
+  end
+
   describe "#plugins_enabled?" do
     it "returns true if the env is not set" do
       with_temp_env("VAGRANT_NO_PLUGINS" => nil) do