Add context to the object-interface methods.

Make necessary changes to xl fs azure sia

cmd/logger/log.go

@@ -0,0 +1,61 @@
+/*
+ * 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"
+
+// Key used for ContextSet/Get
+const contextKey = "reqInfo"
+
+// 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 accomodated by above fields
+}
+
+// AppendTags - appends key/val to ReqInfo.Tags
+func (r *ReqInfo) AppendTags(key string, val string) {
+	if r == nil {
+		return
+	}
+	r.Tags = append(r.Tags, KeyVal{key, val})
+}
+
+// ContextSet sets ReqInfo in the context.
+func ContextSet(ctx context.Context, req *ReqInfo) context.Context {
+	return context.WithValue(ctx, contextKey, req)
+}
+
+// ContextGet returns ReqInfo if set.
+func ContextGet(ctx context.Context) *ReqInfo {
+	r, ok := ctx.Value(contextKey).(*ReqInfo)
+	if ok {
+		return r
+	}
+	return nil
+}