Use opentracing_grpc_propagate_context when necessary

internal/ingress/controller/template/template.go

@@ -159,6 +159,7 @@ var (
 		"stripLocationModifer":         stripLocationModifer,
 		"buildCustomErrorDeps":         buildCustomErrorDeps,
 		"collectCustomErrorsPerServer": collectCustomErrorsPerServer,
+		"opentracingPropagateContext":  opentracingPropagateContext,
 	}
 )
 
@@ -954,3 +955,17 @@ func collectCustomErrorsPerServer(input interface{}) []int {
 
 	return uniqueCodes
 }
+
+func opentracingPropagateContext(loc interface{}) string {
+	location, ok := loc.(*ingress.Location)
+	if !ok {
+		glog.Errorf("expected a '*ingress.Location' type but %T was returned", loc)
+		return "opentracing_propagate_context"
+	}
+
+	if location.BackendProtocol == "GRPC" || location.BackendProtocol == "GRPCS" {
+		return "opentracing_grpc_propagate_context"
+	}
+
+	return "opentracing_propagate_context"
+}

internal/ingress/controller/template/template_test.go

@@ -834,3 +834,21 @@ func TestEscapeLiteralDollar(t *testing.T) {
 		t.Errorf("Expected %v but returned %v", expected, escapedPath)
 	}
 }
+
+func Test_opentracingPropagateContext(t *testing.T) {
+	tests := map[interface{}]string{
+		&ingress.Location{BackendProtocol: "HTTP"}:  "opentracing_propagate_context",
+		&ingress.Location{BackendProtocol: "HTTPS"}: "opentracing_propagate_context",
+		&ingress.Location{BackendProtocol: "GRPC"}:  "opentracing_grpc_propagate_context",
+		&ingress.Location{BackendProtocol: "GRPCS"}: "opentracing_grpc_propagate_context",
+		&ingress.Location{BackendProtocol: "AJP"}:   "opentracing_propagate_context",
+		"not a location": "opentracing_propagate_context",
+	}
+
+	for loc, expectedDirective := range tests {
+		actualDirective := opentracingPropagateContext(loc)
+		if actualDirective != expectedDirective {
+			t.Errorf("Expected %v but returned %v", expectedDirective, actualDirective)
+		}
+	}
+}