fix shadowing issue in logger (#5830)

cmd/logger/reqinfo.go

@@ -0,0 +1,99 @@
+/*
+ * Minio Cloud Storage, (C) 2018 Minio, Inc.
+ *
+ * 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 logger
+
+import (
+	"context"
+	"fmt"
+	"sync"
+)
+
+// Key used for Get/SetReqInfo
+type contextKeyType string
+
+const contextLogKey = contextKeyType("miniolog")
+
+// KeyVal - appended to ReqInfo.Tags
+type KeyVal struct {
+	Key string
+	Val string
+}
+
+// ReqInfo stores the request info.
+type ReqInfo struct {
+	RemoteHost string   // Client Host/IP
+	UserAgent  string   // User Agent
+	RequestID  string   // x-amz-request-id
+	API        string   // API name - GetObject PutObject NewMultipartUpload etc.
+	BucketName string   // Bucket name
+	ObjectName string   // Object name
+	tags       []KeyVal // Any additional info not accommodated by above fields
+	sync.RWMutex
+}
+
+// NewReqInfo :
+func NewReqInfo(remoteHost, userAgent, requestID, api, bucket, object string) *ReqInfo {
+	req := ReqInfo{}
+	req.RemoteHost = remoteHost
+	req.UserAgent = userAgent
+	req.API = api
+	req.RequestID = requestID
+	req.BucketName = bucket
+	req.ObjectName = object
+	return &req
+}
+
+// AppendTags - appends key/val to ReqInfo.tags
+func (r *ReqInfo) AppendTags(key string, val string) *ReqInfo {
+	if r == nil {
+		return nil
+	}
+	r.Lock()
+	defer r.Unlock()
+	r.tags = append(r.tags, KeyVal{key, val})
+	return r
+}
+
+// GetTags - returns the user defined tags
+func (r *ReqInfo) GetTags() []KeyVal {
+	if r == nil {
+		return nil
+	}
+	r.RLock()
+	defer r.RUnlock()
+	return append([]KeyVal(nil), r.tags...)
+}
+
+// SetReqInfo sets ReqInfo in the context.
+func SetReqInfo(ctx context.Context, req *ReqInfo) context.Context {
+	if ctx == nil {
+		LogIf(context.Background(), fmt.Errorf("context is nil"))
+		return nil
+	}
+	return context.WithValue(ctx, contextLogKey, req)
+}
+
+// GetReqInfo returns ReqInfo if set.
+func GetReqInfo(ctx context.Context) *ReqInfo {
+	if ctx != nil {
+		r, ok := ctx.Value(contextLogKey).(*ReqInfo)
+		if ok {
+			return r
+		}
+	}
+	return nil
+}