Add a health checker service implementation.

- adds the code-generated health service classes to the pb along with
  a README explaining how to regenerate the generated code

- adds an implementation of the Health Checker Service along with unit
  tests and an integration test

Also:
- adds a pb folder
  : in a follow-up PR, all ruby pbs + generated code will be moved to it

1 files changed, 185 insertions, 0 deletions

diff --git a/src/ruby/spec/pb/health/checker_spec.rb b/src/ruby/spec/pb/health/checker_spec.rb
new file mode 100644
index 0000000000..0aeae444fc
--- /dev/null
+++ b/src/ruby/spec/pb/health/checker_spec.rb
@@ -0,0 +1,185 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+require 'grpc'
+require 'grpc/health/v1alpha/health'
+require 'grpc/health/checker'
+
+describe Grpc::Health::Checker do
+  StatusCodes = GRPC::Core::StatusCodes
+  ServingStatus = Grpc::Health::V1alpha::HealthCheckResponse::ServingStatus
+  HCResp = Grpc::Health::V1alpha::HealthCheckResponse
+  HCReq = Grpc::Health::V1alpha::HealthCheckRequest
+  success_tests =
+    [
+      {
+        desc: 'neither host or service are specified',
+        host: '',
+        service: ''
+      }, {
+        desc: 'only the host is specified',
+        host: 'test-fake-host',
+        service: ''
+      }, {
+        desc: 'the host and service are specified',
+        host: 'test-fake-host',
+        service: 'fake-service-1'
+      }, {
+        desc: 'only the service is specified',
+        host: '',
+        service: 'fake-service-2'
+      }
+    ]
+
+  context 'initialization' do
+    it 'can be constructed with no args' do
+      expect(subject).to_not be(nil)
+    end
+  end
+
+  context 'method `add_status` and `check`' do
+    success_tests.each do |t|
+      it "should succeed when #{t[:desc]}" do
+        subject.add_status(t[:host], t[:service], ServingStatus::NOT_SERVING)
+        got = subject.check(HCReq.new(host: t[:host], service: t[:service]),
+                            nil)
+        want = HCResp.new(status: ServingStatus::NOT_SERVING)
+        expect(got).to eq(want)
+      end
+    end
+  end
+
+  context 'method `check`' do
+    success_tests.each do |t|
+      it "should fail with NOT_FOUND when #{t[:desc]}" do
+        blk = proc do
+          subject.check(HCReq.new(host: t[:host], service: t[:service]), nil)
+        end
+        expected_msg = /#{StatusCodes::NOT_FOUND}/
+        expect(&blk).to raise_error GRPC::BadStatus, expected_msg
+      end
+    end
+  end
+
+  context 'method `clear_status`' do
+    success_tests.each do |t|
+      it "should fail after clearing status when #{t[:desc]}" do
+        subject.add_status(t[:host], t[:service], ServingStatus::NOT_SERVING)
+        got = subject.check(HCReq.new(host: t[:host], service: t[:service]),
+                            nil)
+        want = HCResp.new(status: ServingStatus::NOT_SERVING)
+        expect(got).to eq(want)
+
+        subject.clear_status(t[:host], t[:service])
+        blk = proc do
+          subject.check(HCReq.new(host: t[:host], service: t[:service]),
+                        nil)
+        end
+        expected_msg = /#{StatusCodes::NOT_FOUND}/
+        expect(&blk).to raise_error GRPC::BadStatus, expected_msg
+      end
+    end
+  end
+
+  context 'method `clear_all`' do
+    it 'should return NOT_FOUND after being invoked' do
+      success_tests.each do |t|
+        subject.add_status(t[:host], t[:service], ServingStatus::NOT_SERVING)
+        got = subject.check(HCReq.new(host: t[:host], service: t[:service]),
+                            nil)
+        want = HCResp.new(status: ServingStatus::NOT_SERVING)
+        expect(got).to eq(want)
+      end
+
+      subject.clear_all
+
+      success_tests.each do |t|
+        blk = proc do
+          subject.check(HCReq.new(host: t[:host], service: t[:service]), nil)
+        end
+        expected_msg = /#{StatusCodes::NOT_FOUND}/
+        expect(&blk).to raise_error GRPC::BadStatus, expected_msg
+      end
+    end
+  end
+
+  describe 'running on RpcServer' do
+    RpcServer = GRPC::RpcServer
+    StatusCodes = GRPC::Core::StatusCodes
+    CheckerStub = Grpc::Health::Checker.rpc_stub_class
+
+    before(:each) do
+      @server_queue = GRPC::Core::CompletionQueue.new
+      server_host = '0.0.0.0:0'
+      @server = GRPC::Core::Server.new(@server_queue, nil)
+      server_port = @server.add_http2_port(server_host)
+      @host = "localhost:#{server_port}"
+      @ch = GRPC::Core::Channel.new(@host, nil)
+      @client_opts = { channel_override: @ch }
+      server_opts = {
+        server_override: @server,
+        completion_queue_override: @server_queue,
+        poll_period: 1
+      }
+      @srv = RpcServer.new(**server_opts)
+    end
+
+    after(:each) do
+      @srv.stop
+    end
+
+    it 'should receive the correct status', server: true do
+      @srv.handle(subject)
+      subject.add_status('', '', ServingStatus::NOT_SERVING)
+      t = Thread.new { @srv.run }
+      @srv.wait_till_running
+
+      stub = CheckerStub.new(@host, **@client_opts)
+      got = stub.check(HCReq.new)
+      want = HCResp.new(status: ServingStatus::NOT_SERVING)
+      expect(got).to eq(want)
+      @srv.stop
+      t.join
+    end
+
+    it 'should fail on unknown services', server: true do
+      @srv.handle(subject)
+      t = Thread.new { @srv.run }
+      @srv.wait_till_running
+      blk = proc do
+        stub = CheckerStub.new(@host, **@client_opts)
+        stub.check(HCReq.new(host: 'unknown', service: 'unknown'))
+      end
+      expected_msg = /#{StatusCodes::NOT_FOUND}/
+      expect(&blk).to raise_error GRPC::BadStatus, expected_msg
+      @srv.stop
+      t.join
+    end
+  end
+end