Merge branch 'plugin-manifest'

Fixes CHEF-4909

2 files changed, 117 insertions, 3 deletions

diff --git a/lib/chef/knife/core/subcommand_loader.rb b/lib/chef/knife/core/subcommand_loader.rb
index f18bc6619e..0489c726b3 100644
--- a/lib/chef/knife/core/subcommand_loader.rb
+++ b/lib/chef/knife/core/subcommand_loader.rb
@@ -60,9 +60,13 @@ class Chef
       # subcommand loader has been modified to load the plugins by using Kernel.load
       # with the absolute path.
       def gem_and_builtin_subcommands
-        # search all gems for chef/knife/*.rb
-        require 'rubygems'
-        find_subcommands_via_rubygems
+        if have_plugin_manifest?
+          find_subcommands_via_manifest
+        else
+          # search all gems for chef/knife/*.rb
+          require 'rubygems'
+          find_subcommands_via_rubygems
+        end
       rescue LoadError
         find_subcommands_via_dirglob
       end
@@ -71,6 +75,36 @@ class Chef
         @subcommand_files ||= (gem_and_builtin_subcommands.values + site_subcommands).flatten.uniq
       end
 
+      # If the user has created a ~/.chef/plugin_manifest.json file, we'll use
+      # that instead of inspecting the on-system gems to find the plugins. The
+      # file format is expected to look like:
+      #
+      #   { "plugins": {
+      #       "knife-ec2": {
+      #         "paths": [
+      #           "/home/alice/.rubymanagerthing/gems/knife-ec2-x.y.z/lib/chef/knife/ec2_server_create.rb",
+      #           "/home/alice/.rubymanagerthing/gems/knife-ec2-x.y.z/lib/chef/knife/ec2_server_delete.rb"
+      #         ]
+      #       }
+      #     }
+      #   }
+      #
+      # Extraneous content in this file is ignored. This intentional so that we
+      # can adapt the file format for potential behavior changes to knife in
+      # the future.
+      def find_subcommands_via_manifest
+        # Format of subcommand_files is "relative_path" (something you can
+        # Kernel.require()) => full_path. The relative path isn't used
+        # currently, so we just map full_path => full_path.
+        subcommand_files = {}
+        plugin_manifest["plugins"].each do |plugin_name, plugin_manifest|
+          plugin_manifest["paths"].each do |cmd_path|
+            subcommand_files[cmd_path] = cmd_path
+          end
+        end
+        subcommand_files.merge(find_subcommands_via_dirglob)
+      end
+
       def find_subcommands_via_dirglob
         # The "require paths" of the core knife subcommands bundled with chef
         files = Dir[File.expand_path('../../../knife/*.rb', __FILE__)]
@@ -93,6 +127,18 @@ class Chef
         subcommand_files.merge(find_subcommands_via_dirglob)
       end
 
+      def have_plugin_manifest?
+        ENV["HOME"] && File.exist?(plugin_manifest_path)
+      end
+
+      def plugin_manifest
+        Chef::JSONCompat.from_json(File.read(plugin_manifest_path))
+      end
+
+      def plugin_manifest_path
+        File.join(ENV['HOME'], '.chef', 'plugin_manifest.json')
+      end
+
       private
 
       def find_files_latest_gems(glob, check_load_path=true)
diff --git a/spec/unit/knife/core/subcommand_loader_spec.rb b/spec/unit/knife/core/subcommand_loader_spec.rb
index b630f4a958..08e6a0bbc1 100644
--- a/spec/unit/knife/core/subcommand_loader_spec.rb
+++ b/spec/unit/knife/core/subcommand_loader_spec.rb
@@ -20,6 +20,7 @@ require 'spec_helper'
 
 describe Chef::Knife::SubcommandLoader do
   before do
+
     @home = File.join(CHEF_SPEC_DATA, 'knife-home')
     @env = {'HOME' => @home}
     @loader = Chef::Knife::SubcommandLoader.new(File.join(CHEF_SPEC_DATA, 'knife-site-subcommands'), @env)
@@ -71,4 +72,71 @@ describe Chef::Knife::SubcommandLoader do
     expected_command = File.join(CHEF_SPEC_DATA, 'knife-site-subcommands', 'plugins', 'knife', 'example_subcommand.rb')
     @loader.site_subcommands.should include(expected_command)
   end
+
+  describe "finding 3rd party plugins" do 
+    let(:env_home) { "/home/alice" }
+    let(:manifest_path) { env_home + "/.chef/plugin_manifest.json" }
+
+    before do
+      env_dup = ENV.to_hash
+      ENV.stub(:[]).and_return { |key| env_dup[key] }
+      ENV.stub(:[]).with("HOME").and_return(env_home)
+    end
+
+    context "when there is not a ~/.chef/plugin_manifest.json file" do
+      before do
+        File.stub(:exist?).with(manifest_path).and_return(false)
+      end
+
+      it "searches rubygems for plugins" do
+        Gem::Specification.should_receive(:latest_specs).and_call_original
+        @loader.subcommand_files.each do |require_path|
+          require_path.should match(/chef\/knife\/.*|plugins\/knife\/.*/)
+        end
+      end
+
+      context "and HOME environment variable is not set" do
+        before do
+          ENV.stub(:[]).with("HOME").and_return(nil)
+        end
+
+        it "searches rubygems for plugins" do
+          Gem::Specification.should_receive(:latest_specs).and_call_original
+          @loader.subcommand_files.each do |require_path|
+            require_path.should match(/chef\/knife\/.*|plugins\/knife\/.*/)
+          end
+        end
+      end
+
+    end
+
+    context "when there is a ~/.chef/plugin_manifest.json file" do
+      let(:ec2_server_create_plugin) { "/usr/lib/ruby/gems/knife-ec2-0.5.12/lib/chef/knife/ec2_server_create.rb" }
+
+      let(:manifest_content) do
+        { "plugins" => {
+            "knife-ec2" => {
+              "paths" => [
+                ec2_server_create_plugin
+              ]
+            }
+          }
+        }
+      end
+
+      let(:manifest_json) { Chef::JSONCompat.to_json(manifest_content) }
+
+      before do
+        File.stub(:exist?).with(manifest_path).and_return(true)
+        File.stub(:read).with(manifest_path).and_return(manifest_json)
+      end
+
+      it "uses paths from the manifest instead of searching gems" do
+        Gem::Specification.should_not_receive(:latest_specs).and_call_original
+        @loader.subcommand_files.should include(ec2_server_create_plugin)
+      end
+
+    end
+  end
+
 end