Merge pull request #5731 from chef/tm/versioned_api

Beginning of automatic API version detection

7 files changed, 381 insertions, 0 deletions

diff --git a/lib/chef/http/api_versions.rb b/lib/chef/http/api_versions.rb
new file mode 100644
index 0000000000..e164da262d
--- /dev/null
+++ b/lib/chef/http/api_versions.rb
@@ -0,0 +1,50 @@
+#--
+# Copyright:: Copyright 2017, 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 "chef/server_api_versions"
+
+class Chef
+  class HTTP
+    # An HTTP middleware to retrieve and store the Chef Server's minimum
+    # and maximum supported API versions.
+    class APIVersions
+
+      def initialize(options = {})
+      end
+
+      def handle_request(method, url, headers = {}, data = false)
+        [method, url, headers, data]
+      end
+
+      def handle_response(http_response, rest_request, return_value)
+        if http_response.key?("x-ops-server-api-version")
+          ServerAPIVersions.instance.set_versions(http_response["x-ops-server-api-version"])
+        end
+        [http_response, rest_request, return_value]
+      end
+
+      def stream_response_handler(response)
+        nil
+      end
+
+      def handle_stream_complete(http_response, rest_request, return_value)
+        [http_response, rest_request, return_value]
+      end
+
+    end
+  end
+end
diff --git a/lib/chef/mixin/versioned_api.rb b/lib/chef/mixin/versioned_api.rb
new file mode 100644
index 0000000000..9c2f2f4cdb
--- /dev/null
+++ b/lib/chef/mixin/versioned_api.rb
@@ -0,0 +1,69 @@
+#--
+# Copyright:: Copyright 2017, 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.
+#
+
+class Chef
+  module Mixin
+    module VersionedAPI
+
+      def minimum_api_version(version = nil)
+        if version
+          @minimum_api_version = version
+        else
+          @minimum_api_version
+        end
+      end
+
+    end
+
+    module VersionedAPIFactory
+
+      def versioned_interfaces
+        @versioned_interfaces ||= []
+      end
+
+      def add_versioned_api_class(klass)
+        versioned_interfaces << klass
+      end
+
+      def versioned_api_class
+        versioned_interfaces.select do |klass|
+          version = klass.send(:minimum_api_version)
+          # min and max versions will be nil if we've not made a request to the server yet,
+          # in which case we'll just start with the highest version and see what happens
+          ServerAPIVersions.instance.min_server_version.nil? || (version >= ServerAPIVersions.instance.min_server_version && version <= ServerAPIVersions.instance.max_server_version)
+        end
+          .sort { |a, b| a.send(:minimum_api_version) <=> b.send(:minimum_api_version) }
+          .last
+      end
+
+      def def_versioned_delegator(method)
+        line_no = __LINE__; str = %{
+          def self.#{method}(*args, &block)
+            versioned_api_class.__send__(:#{method}, *args, &block)
+          end
+        }
+        module_eval(str, __FILE__, line_no)
+      end
+
+      def new(*args)
+        object = versioned_api_class.allocate
+        object.send(:initialize, *args)
+        object
+      end
+    end
+  end
+end
diff --git a/lib/chef/server_api.rb b/lib/chef/server_api.rb
index d233d25232..2bdc5d9fe8 100644
--- a/lib/chef/server_api.rb
+++ b/lib/chef/server_api.rb
@@ -24,6 +24,7 @@ require "chef/http/json_input"
 require "chef/http/json_output"
 require "chef/http/remote_request_id"
 require "chef/http/validate_content_length"
+require "chef/http/api_versions"
 
 class Chef
   class ServerAPI < Chef::HTTP
@@ -42,6 +43,7 @@ class Chef
     use Chef::HTTP::Decompressor
     use Chef::HTTP::Authenticator
     use Chef::HTTP::RemoteRequestID
+    use Chef::HTTP::APIVersions
 
     # ValidateContentLength should come after Decompressor
     # because the order of middlewares is reversed when handling
diff --git a/lib/chef/server_api_versions.rb b/lib/chef/server_api_versions.rb
new file mode 100644
index 0000000000..68dfd5ac90
--- /dev/null
+++ b/lib/chef/server_api_versions.rb
@@ -0,0 +1,40 @@
+#--
+# Copyright:: Copyright 2017, 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 "singleton"
+
+class Chef
+  class ServerAPIVersions
+    include Singleton
+
+    def set_versions(versions)
+      @versions ||= versions
+    end
+
+    def min_server_version
+      !@versions.nil? ? @versions["min_version"] : nil
+    end
+
+    def max_server_version
+      !@versions.nil? ? @versions["max_version"] : nil
+    end
+
+    def reset!
+      @versions = nil
+    end
+  end
+end
diff --git a/spec/unit/http/api_versions_spec.rb b/spec/unit/http/api_versions_spec.rb
new file mode 100644
index 0000000000..79c97a1b69
--- /dev/null
+++ b/spec/unit/http/api_versions_spec.rb
@@ -0,0 +1,69 @@
+#
+# Copyright:: Copyright 2017, 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::HTTP::APIVersions do
+  class TestVersionClient < Chef::HTTP
+    use Chef::HTTP::APIVersions
+  end
+
+  before do
+    Chef::ServerAPIVersions.instance.reset!
+  end
+
+  let(:method) { "GET" }
+  let(:url) { "http://dummy.com" }
+  let(:headers) { {} }
+  let(:data) { false }
+
+  let(:request) {}
+  let(:return_value) { "200" }
+
+  # Test Variables
+  let(:response_body) { "Thanks for checking in." }
+  let(:response_headers) do
+    {
+      "x-ops-server-api-version" => { "min_version" => 0, "max_version" => 2 },
+    }
+  end
+
+  let(:response) do
+    m = double("HttpResponse", :body => response_body)
+    allow(m).to receive(:key?).with("x-ops-server-api-version").and_return(true)
+    allow(m).to receive(:[]) do |key|
+      response_headers[key]
+    end
+
+    m
+  end
+
+  let(:middleware) do
+    client = TestVersionClient.new(url)
+    client.middlewares[0]
+  end
+
+  def run_api_version_handler
+    middleware.handle_request(method, url, headers, data)
+    middleware.handle_response(response, request, return_value)
+  end
+
+  it "correctly stores server api versions" do
+    run_api_version_handler
+    expect(Chef::ServerAPIVersions.instance.min_server_version).to eq(0)
+  end
+end
diff --git a/spec/unit/mixin/versioned_api_spec.rb b/spec/unit/mixin/versioned_api_spec.rb
new file mode 100644
index 0000000000..4f2418ca24
--- /dev/null
+++ b/spec/unit/mixin/versioned_api_spec.rb
@@ -0,0 +1,107 @@
+#
+# Copyright:: Copyright 2015-2017, 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"
+require "chef/mixin/versioned_api"
+
+describe Chef::Mixin::VersionedAPI do
+  let(:dummy_class) { Class.new { extend Chef::Mixin::VersionedAPI } }
+
+  it "allows a class to declare the minimum supported API version" do
+    dummy_class.minimum_api_version 3
+    expect(dummy_class.minimum_api_version).to eq(3)
+  end
+end
+
+describe Chef::Mixin::VersionedAPIFactory do
+  class V1Class; extend Chef::Mixin::VersionedAPI; minimum_api_version 1; end
+  class V2Class; extend Chef::Mixin::VersionedAPI; minimum_api_version 2; end
+  class V3Class; extend Chef::Mixin::VersionedAPI; minimum_api_version 3; end
+
+  let(:factory_class) { Class.new { extend Chef::Mixin::VersionedAPIFactory } }
+
+  before do
+    Chef::ServerAPIVersions.instance.reset!
+  end
+
+  describe "#add_versioned_api_class" do
+    it "adds a target class" do
+      factory_class.add_versioned_api_class V1Class
+      expect(factory_class.versioned_interfaces).to eq([V1Class])
+    end
+
+    it "can be called many times" do
+      factory_class.add_versioned_api_class V1Class
+      factory_class.add_versioned_api_class V2Class
+      expect(factory_class.versioned_interfaces).to eq([V1Class, V2Class])
+    end
+  end
+
+  describe "#versioned_api_class" do
+    describe "with no known versions" do
+      it "with one class it returns that class" do
+        factory_class.add_versioned_api_class V2Class
+        expect(factory_class.versioned_api_class.minimum_api_version).to eq(2)
+      end
+
+      it "with many classes it returns the highest minimum version" do
+        factory_class.add_versioned_api_class V1Class
+        factory_class.add_versioned_api_class V2Class
+        factory_class.add_versioned_api_class V3Class
+        expect(factory_class.versioned_api_class.minimum_api_version).to eq(3)
+      end
+    end
+
+    describe "with a known version" do
+      it "with one class it returns that class" do
+        Chef::ServerAPIVersions.instance.set_versions({ "min_version" => 0, "max_version" => 2 })
+        factory_class.add_versioned_api_class V2Class
+        expect(factory_class.versioned_api_class.minimum_api_version).to eq(2)
+      end
+
+      it "with a maximum version it returns the highest possible versioned class" do
+        Chef::ServerAPIVersions.instance.set_versions({ "min_version" => 0, "max_version" => 2 })
+        factory_class.add_versioned_api_class V1Class
+        factory_class.add_versioned_api_class V2Class
+        factory_class.add_versioned_api_class V3Class
+        expect(factory_class.versioned_api_class.minimum_api_version).to eq(2)
+      end
+    end
+
+    it "with no classes it returns nil" do
+      expect(factory_class.versioned_api_class).to be_nil
+    end
+  end
+
+  describe "#new" do
+    it "creates an instance of the versioned class" do
+      factory_class.add_versioned_api_class V2Class
+      expect { factory_class.new }.to_not raise_error
+      expect(factory_class.new.class).to eq(V2Class)
+    end
+  end
+
+  describe "#def_versioned_delegator" do
+    it "delegates the method to the correct class" do
+      factory_class.add_versioned_api_class V2Class
+      factory_class.def_versioned_delegator("test_method")
+      expect(V2Class).to receive(:test_method).with("test message").and_return(true)
+
+      factory_class.test_method("test message")
+    end
+  end
+end
diff --git a/spec/unit/server_api_versions_spec.rb b/spec/unit/server_api_versions_spec.rb
new file mode 100644
index 0000000000..43445eb825
--- /dev/null
+++ b/spec/unit/server_api_versions_spec.rb
@@ -0,0 +1,44 @@
+#
+# Copyright:: Copyright 2017, 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::ServerAPIVersions do
+  before do
+    Chef::ServerAPIVersions.instance.reset!
+  end
+
+  describe "#min_server_version" do
+    it "returns nil if no versions have been recorded" do
+      expect(Chef::ServerAPIVersions.instance.min_server_version).to be_nil
+    end
+    it "returns the correct value" do
+      Chef::ServerAPIVersions.instance.set_versions({ "min_version" => 0, "max_version" => 2 })
+      expect(Chef::ServerAPIVersions.instance.min_server_version).to eq(0)
+    end
+  end
+
+  describe "#max_server_version" do
+    it "returns nil if no versions have been recorded" do
+      expect(Chef::ServerAPIVersions.instance.max_server_version).to be_nil
+    end
+    it "returns the correct value" do
+      Chef::ServerAPIVersions.instance.set_versions({ "min_version" => 0, "max_version" => 2 })
+      expect(Chef::ServerAPIVersions.instance.max_server_version).to eq(2)
+    end
+  end
+end