Differentiate between returning a Twirp::Error and raising a Twirp::Exception

lib/twirp.rb

@@ -1,3 +1,4 @@
 require_relative 'twirp/version'
 require_relative 'twirp/error'
-require_relative 'twirp/service'
+require_relative 'twirp/exception'
+require_relative 'twirp/service'

lib/twirp/error.rb

@@ -29,7 +29,7 @@ module Twirp
   ERROR_CODES = ERROR_CODES_TO_HTTP_STATUS.keys
 
   # Twirp::Error represents a valid error from a Twirp service
-	class Error < StandardError
+	class Error
 
     # Wrap an arbitrary error as a Twirp :internal
     def self.InternalWith(err)

lib/twirp/exception.rb

@@ -0,0 +1,21 @@
+require_relative "./error"
+
+module Twirp
+
+  class Exception < StandardError
+
+    def initialize(code, msg, meta=nil)
+      @twerr = Twirp::Error.new(code, msg, meta)
+    end
+
+    def message
+      "#{code}: #{msg}"
+    end
+
+    def code; @twerr.code; end
+    def msg; @twerr.msg; end
+    def meta; @twerr.meta; end
+    def to_json; @twerr.to_json; end
+    def as_json; @twerr.as_json; end
+  end
+end

lib/twirp/service.rb

@@ -96,11 +96,8 @@ module Twirp
         resp = @handler.send(rpc[:handler_method], proto_req)
         return rack_response_from_handler(rpc, content_type, resp)
 
-      rescue Twirp::Error => twerr
+      rescue Twirp::Exception => twerr
         error_response(twerr)
-      rescue StandardError => err
-        puts err.backtrace
-        error_response(Twirp::Error.InternalWith(err))
       end
     end
 

test/service_test.rb

@@ -180,8 +180,8 @@ class ServiceTest < Minitest::Test
     assert_equal Example::Hat.new(inches: 0, color: ""), Example::Hat.decode(body[0])
   end
 
-  # Handler should be able to return Twirp::Exception values, that will trigger error responses
-  def test_handler_returns_twirp_exception
+  # Handler should be able to return Twirp::Error values, that will trigger error responses
+  def test_handler_returns_twirp_error
     svc = Example::Haberdasher.new(HaberdasherHandler.new do |size|
       return Twirp::Error.new(:invalid_argument, "I don't like that size")
     end)
@@ -199,7 +199,7 @@ class ServiceTest < Minitest::Test
   # Handler should be able to raise a Twirp::Exception, that will trigger error responses
   def test_handler_raises_twirp_exception
     svc = Example::Haberdasher.new(HaberdasherHandler.new do |size|
-      raise Twirp::Error.new(:invalid_argument, "I don't like that size")
+      raise Twirp::Exception.new(:invalid_argument, "I don't like that size")
     end)
 
     env = proto_req "/twirp/example.Haberdasher/MakeHat", Example::Size.new(inches: 666)