Add chef_handler resource from chef_handler cookbookhandler_resource

Merges the helper library into the action_class, but otherwise this is
the same as the cookbook.

Signed-off-by: Tim Smith <tsmith@chef.io>

2 files changed, 165 insertions, 0 deletions

diff --git a/lib/chef/resource/chef_handler.rb b/lib/chef/resource/chef_handler.rb
new file mode 100644
index 0000000000..2c80a1a9c9
--- /dev/null
+++ b/lib/chef/resource/chef_handler.rb
@@ -0,0 +1,130 @@
+#
+# Author:: Seth Chisamore <schisamo@chef.io>
+# Copyright:: 2011-2018, Chef Software, Inc <legal@chef.io>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+class Chef
+  class Resource
+    class ChefHandler < Chef::Resource
+      resource_name :chef_handler
+      provides :chef_handler
+
+      description "Use the chef_handler resource to install or uninstall Chef reporting/exception handlers."
+      introduced "14.0"
+
+      property :class_name, String,
+               description: "The name of the handler class (can be module name-spaced).",
+               name_property: true
+
+      property :source, String,
+               description: "The full path to the handler file. Can also be a gem path if the handler ships as part of a Ruby gem."
+
+      property :arguments, [Array, Hash],
+               description: "Arguments to pass the handler's class initializer.",
+               default: []
+
+      property :type, Hash,
+               description: "The type of Chef Handler to register as, i.e. :report, :exception or both.",
+               default: { report: true, exception: true }
+
+      # supports means a different thing in chef-land so we renamed it but
+      # wanted to make sure we didn't break the world
+      alias_method :supports, :type
+
+      # This action needs to find an rb file that presumably contains the indicated class in it and the
+      # load that file. It then instantiates that class by name and registers it as a handler.
+      action :enable do
+        description "Enables the Chef handler for the current Chef run on the current node"
+
+        class_name = new_resource.class_name
+        new_resource.type.each do |type, enable|
+          next unless enable
+
+          unregister_handler(type, class_name)
+        end
+
+        handler = nil
+
+        require new_resource.source unless new_resource.source.nil?
+
+        _, klass = get_class(class_name)
+        handler = klass.send(:new, *collect_args(new_resource.arguments))
+
+        new_resource.type.each do |type, enable|
+          next unless enable
+          register_handler(type, handler)
+        end
+      end
+
+      action :disable do
+        description "Disables the Chef handler for the current Chef run on the current node"
+
+        new_resource.type.each_key do |type|
+          unregister_handler(type, new_resource.class_name)
+        end
+      end
+
+      action_class do
+        # Registers a handler in Chef::Config.
+        #
+        # @param handler_type [Symbol] such as :report or :exception.
+        # @param handler [Chef::Handler] handler to register.
+        def register_handler(handler_type, handler)
+          Chef::Log.info("Enabling #{handler.class.name} as a #{handler_type} handler.")
+          Chef::Config.send("#{handler_type}_handlers") << handler
+        end
+
+        # Removes all handlers that match the given class name in Chef::Config.
+        #
+        # @param handler_type [Symbol] such as :report or :exception.
+        # @param class_full_name [String] such as 'Chef::Handler::ErrorReport'.
+        def unregister_handler(handler_type, class_full_name)
+          Chef::Config.send("#{handler_type}_handlers").delete_if do |v|
+            # avoid a bit of log spam
+            if v.class.name == class_full_name
+              Chef::Log.info("Disabling #{class_full_name} as a #{handler_type} handler.")
+              true
+            end
+          end
+        end
+
+        # Walks down the namespace heirarchy to return the class object for the given class name.
+        # If the class is not available, NameError is thrown.
+        #
+        # @param class_full_name [String] full class name such as 'Chef::Handler::Foo' or 'MyHandler'.
+        # @return [Array] parent class and child class.
+        def get_class(class_full_name)
+          ancestors = class_full_name.split("::")
+          class_name = ancestors.pop
+
+          # We need to search the ancestors only for the first/uppermost namespace of the class, so we
+          # need to enable the #const_get inherit paramenter only when we are searching in Kernel scope
+          # (see COOK-4117).
+          parent = ancestors.inject(Kernel) { |scope, const_name| scope.const_get(const_name, scope === Kernel) }
+          child = parent.const_get(class_name, parent === Kernel)
+          [parent, child]
+        end
+
+        def collect_args(resource_args = [])
+          if resource_args.is_a? Array
+            resource_args
+          else
+            [resource_args]
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/spec/unit/resource/chef_handler_spec.rb b/spec/unit/resource/chef_handler_spec.rb
new file mode 100644
index 0000000000..7cba0c7fe3
--- /dev/null
+++ b/spec/unit/resource/chef_handler_spec.rb
@@ -0,0 +1,35 @@
+#
+# Copyright:: Copyright 2018, Chef Software, Inc.
+# License:: Apache License, Version 2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+require "spec_helper"
+
+describe Chef::Resource::ChefHandler do
+
+  let(:resource) { Chef::Resource::ChefHandler.new("foo") }
+
+  it "has a resource name of :chef_handler" do
+    expect(resource.resource_name).to eql(:chef_handler)
+  end
+
+  it "has a default action of enable" do
+    expect(resource.action).to eql([:enable])
+  end
+
+  it "the class_name property is the name property" do
+    expect(resource.class_name).to eql("foo")
+  end
+end