vendor: update buildkit to 2943a0838

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/google.golang.org/grpc/internal/grpclog/prefixLogger.go

@@ -0,0 +1,63 @@
+/*
+ *
+ * Copyright 2020 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpclog
+
+// PrefixLogger does logging with a prefix.
+//
+// Logging method on a nil logs without any prefix.
+type PrefixLogger struct {
+	prefix string
+}
+
+// Infof does info logging.
+func (pl *PrefixLogger) Infof(format string, args ...interface{}) {
+	if pl != nil {
+		// Handle nil, so the tests can pass in a nil logger.
+		format = pl.prefix + format
+	}
+	Logger.Infof(format, args...)
+}
+
+// Warningf does warning logging.
+func (pl *PrefixLogger) Warningf(format string, args ...interface{}) {
+	if pl != nil {
+		format = pl.prefix + format
+	}
+	Logger.Warningf(format, args...)
+}
+
+// Errorf does error logging.
+func (pl *PrefixLogger) Errorf(format string, args ...interface{}) {
+	if pl != nil {
+		format = pl.prefix + format
+	}
+	Logger.Errorf(format, args...)
+}
+
+// Debugf does info logging at verbose level 2.
+func (pl *PrefixLogger) Debugf(format string, args ...interface{}) {
+	if Logger.V(2) {
+		pl.Infof(format, args...)
+	}
+}
+
+// NewPrefixLogger creates a prefix logger with the given prefix.
+func NewPrefixLogger(prefix string) *PrefixLogger {
+	return &PrefixLogger{prefix: prefix}
+}