1 files changed, 117 insertions, 0 deletions
diff --git a/lib/gitlab/pages_client.rb b/lib/gitlab/pages_client.rb
new file mode 100644
index 00000000000..7b358a3bd1b
--- /dev/null
+++ b/lib/gitlab/pages_client.rb
@@ -0,0 +1,117 @@
+module Gitlab
+  class PagesClient
+    class << self
+      attr_reader :certificate, :token
+
+      def call(service, rpc, request, timeout: nil)
+        kwargs = request_kwargs(timeout)
+        stub(service).__send__(rpc, request, kwargs) # rubocop:disable GitlabSecurity/PublicSend
+      end
+
+      # This function is not thread-safe. Call it from an initializer only.
+      def read_or_create_token
+        @token = read_token
+      rescue Errno::ENOENT
+        # TODO: uncomment this when omnibus knows how to write the token file for us
+        # https://gitlab.com/gitlab-org/omnibus-gitlab/merge_requests/2466
+        #
+        # write_token(SecureRandom.random_bytes(64))
+        #
+        # # Read from disk in case someone else won the race and wrote the file
+        # # before us. If this fails again let the exception bubble up.
+        # @token = read_token
+      end
+
+      # This function is not thread-safe. Call it from an initializer only.
+      def load_certificate
+        cert_path = config.certificate
+        return unless cert_path.present?
+
+        @certificate = File.read(cert_path)
+      end
+
+      def ping
+        request = Grpc::Health::V1::HealthCheckRequest.new
+        call(:health_check, :check, request, timeout: 5.seconds)
+      end
+
+      private
+
+      def request_kwargs(timeout)
+        encoded_token = Base64.strict_encode64(token.to_s)
+        metadata = {
+          'authorization' => "Bearer #{encoded_token}"
+        }
+
+        result = { metadata: metadata }
+
+        return result unless timeout
+
+        # Do not use `Time.now` for deadline calculation, since it
+        # will be affected by Timecop in some tests, but grpc's c-core
+        # uses system time instead of timecop's time, so tests will fail
+        # `Time.at(Process.clock_gettime(Process::CLOCK_REALTIME))` will
+        # circumvent timecop
+        deadline = Time.at(Process.clock_gettime(Process::CLOCK_REALTIME)) + timeout
+        result[:deadline] = deadline
+
+        result
+      end
+
+      def stub(name)
+        stub_class(name).new(address, grpc_creds)
+      end
+
+      def stub_class(name)
+        if name == :health_check
+          Grpc::Health::V1::Health::Stub
+        else
+          # TODO use pages namespace
+          Gitaly.const_get(name.to_s.camelcase.to_sym).const_get(:Stub)
+        end
+      end
+
+      def address
+        addr = config.address
+        addr = addr.sub(%r{^tcp://}, '') if URI(addr).scheme == 'tcp'
+        addr
+      end
+
+      def grpc_creds
+        if address.start_with?('unix:')
+          :this_channel_is_insecure
+        elsif @certificate
+          GRPC::Core::ChannelCredentials.new(@certificate)
+        else
+          # Use system certificate pool
+          GRPC::Core::ChannelCredentials.new
+        end
+      end
+
+      def config
+        Gitlab.config.pages.admin
+      end
+
+      def read_token
+        File.read(token_path)
+      end
+
+      def token_path
+        Rails.root.join('.gitlab_pages_secret').to_s
+      end
+
+      def write_token(new_token)
+        Tempfile.open(File.basename(token_path), File.dirname(token_path),  encoding: 'ascii-8bit') do |f|
+          f.write(new_token)
+          f.close
+          File.link(f.path, token_path)
+        end
+      rescue Errno::EACCES => ex
+        # TODO stop rescuing this exception in GitLab 11.0 https://gitlab.com/gitlab-org/gitlab-ce/issues/45672
+        Rails.logger.error("Could not write pages admin token file: #{ex}")
+      rescue Errno::EEXIST
+        # Another process wrote the token file concurrently with us. Use their token, not ours.
+      end
+    end
+  end
+end