fix(genapi): uint64 fields failing to be unmarshalled (#2492)

uint64 fields get marshalled into json by protobuf as strings, so we
have to tell the json parser to look for strings when unmarshalling.

internal/api/genapi/input.go

@@ -58,6 +58,7 @@ type fieldInfo struct {
 	SubtypeNames      []string
 	Query             bool
 	SkipDefault       bool
+	JsonTags          []string // Appended to a field's `json` tag (comma separated)
 }
 
 type structInfo struct {
@@ -832,6 +833,13 @@ var inputStructs = []*structInfo{
 	{
 		inProto: &sessions.Connection{},
 		outFile: "sessions/connection.gen.go",
+		fieldOverrides: []fieldInfo{
+			// uint64 fields get marshalled by protobuf as strings, so we have
+			// to tell the json parser that their json representation is a
+			// string but they go into Go uint64 types.
+			{Name: "BytesUp", JsonTags: []string{"string"}},
+			{Name: "BytesDown", JsonTags: []string{"string"}},
+		},
 	},
 	{
 		inProto: &sessions.Session{},