Propagate metadata in BadStatus

- allow BadStatus to contain metadata that's populated by keyword args
- on servers, convert raised BadStatus metadata to trailers
- on clients, convert trailers to BadStatus metadata when raising BadStatus

2 files changed, 15 insertions, 8 deletions

diff --git a/src/ruby/lib/grpc/generic/active_call.rb b/src/ruby/lib/grpc/generic/active_call.rb
index 8d63de4145..274372e4d5 100644
--- a/src/ruby/lib/grpc/generic/active_call.rb
+++ b/src/ruby/lib/grpc/generic/active_call.rb
@@ -39,7 +39,10 @@ class Struct
       return nil if status.nil?
       fail GRPC::Cancelled if status.code == GRPC::Core::StatusCodes::CANCELLED
       if status.code != GRPC::Core::StatusCodes::OK
-        fail GRPC::BadStatus.new(status.code, status.details)
+        # raise BadStatus, propagating the metadata if present.
+        md = status.metadata
+        with_sym_keys = Hash[md.each_pair.collect { |x, y| [x.to_sym, y] }]
+        fail GRPC::BadStatus.new(status.code, status.details, **with_sym_keys)
       end
       status
     end
@@ -192,9 +195,13 @@ module GRPC
     # @param details [String] details
     # @param assert_finished [true, false] when true(default), waits for
     # FINISHED.
-    def send_status(code = OK, details = '', assert_finished = false)
+    #
+    # == Keyword Arguments ==
+    # any keyword arguments are treated as metadata to be sent to the server
+    # if a keyword value is a list, multiple metadata for it's key are sent
+    def send_status(code = OK, details = '', assert_finished = false, **kw)
       ops = {
-        SEND_STATUS_FROM_SERVER => Struct::Status.new(code, details)
+        SEND_STATUS_FROM_SERVER => Struct::Status.new(code, details, kw)
       }
       ops[RECV_CLOSE_ON_SERVER] = nil if assert_finished
       @call.run_batch(@cq, self, INFINITE_FUTURE, ops)
diff --git a/src/ruby/lib/grpc/generic/rpc_desc.rb b/src/ruby/lib/grpc/generic/rpc_desc.rb
index 3e48b8e51d..22b80d8938 100644
--- a/src/ruby/lib/grpc/generic/rpc_desc.rb
+++ b/src/ruby/lib/grpc/generic/rpc_desc.rb
@@ -82,10 +82,10 @@ module GRPC
       end
       send_status(active_call, OK, 'OK')
     rescue BadStatus => e
-      # this is raised by handlers that want GRPC to send an application
-      # error code and detail message.
+      # this is raised by handlers that want GRPC to send an application error
+      # code and detail message and some additional app-specific metadata.
       logger.debug("app err: #{active_call}, status:#{e.code}:#{e.details}")
-      send_status(active_call, e.code, e.details)
+      send_status(active_call, e.code, e.details, **e.metadata)
     rescue Core::CallError => e
       # This is raised by GRPC internals but should rarely, if ever happen.
       # Log it, but don't notify the other endpoint..
@@ -135,9 +135,9 @@ module GRPC
       "##{mth.name}: bad arg count; got:#{mth.arity}, want:#{want}, #{msg}"
     end
 
-    def send_status(active_client, code, details)
+    def send_status(active_client, code, details, **kw)
       details = 'Not sure why' if details.nil?
-      active_client.send_status(code, details, code == OK)
+      active_client.send_status(code, details, code == OK, **kw)
     rescue StandardError => e
       logger.warn("Could not send status #{code}:#{details}")
       logger.warn(e)