From 4158f7f9464d7af86610c4558bf7d50c999fefbc Mon Sep 17 00:00:00 2001
From: ston1th <ston1th@giftfish.de>
Date: Wed, 10 Jun 2020 01:22:35 +0200
Subject: [PATCH] added first scheduler

---
 node.go | 52 +++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 39 insertions(+), 13 deletions(-)

diff --git a/node.go b/node.go
index e6b05a5..7a8f89e 100644
--- a/node.go
+++ b/node.go
@@ -12,6 +12,7 @@ var (
 	ErrNodesOffline     = errors.New("one or more nodes are offline")
 	ErrNodesNotSearched = errors.New("one or more nodes could not be searched")
 	ErrEmptyID          = errors.New("id is empty")
+	ErrUnschedulable    = errors.New("no schedulable node found")
 )
 
 type NodeStatus string
@@ -31,17 +32,25 @@ type Node struct {
 	MaxMem     int64      `json:"maxmem"`
 	Disk       int64      `json:"disk"`
 	MaxDisk    int64      `json:"maxdisk"`
-	ServerList ServerList `json:"-"`
+	serverList ServerList `json:"-"`
 }
 
-func (n *Node) MemFreePercent() float64 {
+func (n *Node) memFreePercent() float64 {
 	return float64(n.Mem) / float64(n.MaxMem) * 100
 }
 
+func (n *Node) memUsedPercent() float64 {
+	return float64(n.MaxMem-n.Mem) / float64(n.MaxMem) * 100
+}
+
+func (n *Node) weight() int {
+	return int(n.memUsedPercent()) + (len(n.serverList) * 10)
+}
+
 type NodeList []*Node
 
-func (nl NodeList) sortByFreeMem() {
-	sort.Sort(memSorter(nl))
+func (nl NodeList) sortByWeight() {
+	sort.Sort(weightSorter(nl))
 }
 
 func (nl *NodeList) remove(i int) {
@@ -49,26 +58,28 @@ func (nl *NodeList) remove(i int) {
 	*nl = (*nl)[:len(*nl)-1]
 }
 
-func (nl *NodeList) Filter(filters ...NodeFilter) {
+func (nl *NodeList) filter(filters ...NodeFilter) {
 	for _, f := range filters {
 		f(nl)
 	}
 }
 
-func (nl *NodeList) GetServerList(ctx context.Context, c *NodeClient) (err error) {
+func (nl *NodeList) getServerList(ctx context.Context, c *NodeClient) (err error) {
 	for _, n := range *nl {
-		n.ServerList, err = c.ListServers(ctx, n)
+		n.serverList, err = c.ListServers(ctx, n)
 		if err != nil {
 			return
 		}
 	}
 }
 
-type memSorter NodeList
+type weightSorter NodeList
 
-func (m memSorter) Len() int           { return len(m) }
-func (m memSorter) Less(i, j int) bool { return m[i].MemFreePercent() < m[j].MemFreePercent() }
-func (m memSorter) Swap(i, j int)      { m[i], m[j] = m[j], m[i] }
+func (s weightSorter) Len() int { return len(s) }
+func (s weightSorter) Less(i, j int) bool {
+	return s.weight() < s[j].weight()
+}
+func (s weightSorter) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
 
 type NodeFilter func(*NodeList)
 
@@ -136,7 +147,7 @@ func FilterVMAntiAffinity(url string) NodeFilter {
 			return
 		}
 		for i, n := range *nl {
-			for _, s := range n.ServerList {
+			for _, s := range n.serverList {
 				if s.ID == id {
 					nl.remove(i)
 					return
@@ -150,7 +161,22 @@ type NodeClient struct {
 	client *Client
 }
 
-func (c *NodeClient) Schedule(ctx context.Context) (n *Node, err error) {
+func (c *NodeClient) Schedule(ctx context.Context, filters ...NodeFilter) (n *Node, err error) {
+	nl, err := c.List(ctx)
+	if err != nil {
+		return
+	}
+	err = nl.getServerList(ctx, c)
+	if err != nil {
+		return
+	}
+	nl.filter(filters)
+	nl.sortByWeight()
+	if len(nl) == 0 {
+		err = ErrUnschedulable
+		return
+	}
+	n = nl[0]
 	return
 }