Rework use of context

context/context.go

@@ -0,0 +1,22 @@
+package context
+
+import (
+	"golang.org/x/net/context"
+)
+
+type key int
+
+const (
+	mdKey = key(0)
+)
+
+type MetaData map[string]string
+
+func GetMetaData(ctx context.Context) (MetaData, bool) {
+	md, ok := ctx.Value(mdKey).(MetaData)
+	return md, ok
+}
+
+func WithMetaData(ctx context.Context, md MetaData) context.Context {
+	return context.WithValue(ctx, mdKey, md)
+}