1 files changed, 69 insertions, 0 deletions
diff --git a/src/weed/topology/node_list.go b/src/weed/topology/node_list.go
new file mode 100644
index 000000000..17ab1e0dc
--- /dev/null
+++ b/src/weed/topology/node_list.go
@@ -0,0 +1,69 @@
+package topology
+
+import (
+	"fmt"
+	"math/rand"
+	"weed/storage"
+)
+
+type NodeList struct {
+	nodes  map[NodeId]Node
+	except map[string]Node
+}
+
+func NewNodeList(nodes map[NodeId]Node, except map[string]Node) *NodeList {
+	m := make(map[NodeId]Node, len(nodes)-len(except))
+	for _, n := range nodes {
+		if except[n.String()] == nil {
+			m[n.Id()] = n
+		}
+	}
+	nl := &NodeList{nodes: m}
+	return nl
+}
+
+func (nl *NodeList) FreeSpace() int {
+	freeSpace := 0
+	for _, n := range nl.nodes {
+		freeSpace += n.FreeSpace()
+	}
+	return freeSpace
+}
+
+func (nl *NodeList) RandomlyPickN(n int, min int) ([]Node, bool) {
+	var list []Node
+	for _, n := range nl.nodes {
+		if n.FreeSpace() >= min {
+			list = append(list, n)
+		}
+	}
+	if n > len(list) {
+		return nil, false
+	}
+	for i := n; i > 0; i-- {
+		r := rand.Intn(i)
+		t := list[r]
+		list[r] = list[i-1]
+		list[i-1] = t
+	}
+	return list[len(list)-n:], true
+}
+
+func (nl *NodeList) ReserveOneVolume(randomVolumeIndex int, vid storage.VolumeId) (bool, *DataNode) {
+	for _, node := range nl.nodes {
+		freeSpace := node.FreeSpace()
+		if randomVolumeIndex >= freeSpace {
+			randomVolumeIndex -= freeSpace
+		} else {
+			if node.IsDataNode() && node.FreeSpace() > 0 {
+				fmt.Println("vid =", vid, " assigned to node =", node, ", freeSpace =", node.FreeSpace())
+				return true, node.(*DataNode)
+			}
+			children := node.Children()
+			newNodeList := NewNodeList(children, nl.except)
+			return newNodeList.ReserveOneVolume(randomVolumeIndex, vid)
+		}
+	}
+	return false, nil
+
+}