Update serving response proto (#2390)

* Add health metric field to online response

Signed-off-by: Terence Lim <terencelimxp@gmail.com>

* Update Go SDK

Signed-off-by: Terence Lim <terencelimxp@gmail.com>

go.mod

@@ -24,7 +24,7 @@ require (
 	go.opencensus.io v0.22.3 // indirect
 	golang.org/x/lint v0.0.0-20200302205851-738671d3881b // indirect
 	golang.org/x/net v0.0.0-20201021035429-f5854403a974
-	golang.org/x/tools v0.0.0-20201124005743-911501bfb504 // indirect
+	golang.org/x/tools v0.0.0-20201124165954-ed677e9dcd1e // indirect
 	google.golang.org/grpc v1.29.1
 	google.golang.org/protobuf v1.25.0 // indirect
 	gopkg.in/russross/blackfriday.v2 v2.0.0 // indirect

go.sum

@@ -506,6 +506,8 @@ golang.org/x/tools v0.0.0-20201017001424-6003fad69a88 h1:ZB1XYzdDo7c/O48jzjMkvIj
 golang.org/x/tools v0.0.0-20201017001424-6003fad69a88/go.mod h1:z6u4i615ZeAfBE4XtMziQW1fSVJXACjjbWkB/mvPzlU=
 golang.org/x/tools v0.0.0-20201124005743-911501bfb504 h1:jOKV2ysikH1GANB7t2LotmhyvkkPvl7HQoEXkV6slJA=
 golang.org/x/tools v0.0.0-20201124005743-911501bfb504/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
+golang.org/x/tools v0.0.0-20201124165954-ed677e9dcd1e h1:ieMpTyMW6BN9nTaG7Ucw9wEkBnlD/NuMUFo8TZ+H8SY=
+golang.org/x/tools v0.0.0-20201124165954-ed677e9dcd1e/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=

protos/feast/serving/ServingService.proto

@@ -112,6 +112,9 @@ message GetOnlineFeaturesResponse {
         // Values could be found for entity key, but field values are outside the maximum 
         // allowable range.
         OUTSIDE_MAX_AGE = 4;
+
+        // Values could be found for entity key, but are null and is due to ingestion failures
+        INGESTION_FAILURE = 5;
     }
 }