From 880f93ea6c1dda9a439295d8d12459483947f8f0 Mon Sep 17 00:00:00 2001
From: Garet Halliday <me@garet.holiday>
Date: Mon, 31 Jul 2023 11:59:51 -0600
Subject: [PATCH] fix races
---
lib/gat/pool.go | 57 +++++++++++++++++++++++++++++++++++--------------
1 file changed, 41 insertions(+), 16 deletions(-)
diff --git a/lib/gat/pool.go b/lib/gat/pool.go
index 71ec57df..0c89faf7 100644
--- a/lib/gat/pool.go
+++ b/lib/gat/pool.go
@@ -26,12 +26,13 @@ type RawPool interface {
type recipeWithConns struct {
recipe Recipe
- conns []uuid.UUID
- mu sync.Mutex
+ removed bool
+ conns []uuid.UUID
+ mu sync.Mutex
}
func (T *recipeWithConns) scaleUp(pool *Pool, currentScale int) bool {
- if currentScale >= T.recipe.GetMaxConnections() {
+ if currentScale >= T.recipe.GetMaxConnections() || T.removed {
return false
}
@@ -57,7 +58,7 @@ func (T *recipeWithConns) scaleUp(pool *Pool, currentScale int) bool {
}
func (T *recipeWithConns) scaleDown(pool *Pool, currentScale int) bool {
- if currentScale <= T.recipe.GetMinConnections() {
+ if currentScale <= T.recipe.GetMinConnections() || T.removed {
return false
}
@@ -76,6 +77,10 @@ func (T *recipeWithConns) scaleDown(pool *Pool, currentScale int) bool {
}
func (T *recipeWithConns) scale(pool *Pool, currentScale int, amount int) int {
+ if T.removed {
+ return amount
+ }
+
if amount > 0 {
for amount > 0 {
if T.scaleUp(pool, currentScale) {
@@ -99,6 +104,10 @@ func (T *recipeWithConns) scale(pool *Pool, currentScale int, amount int) int {
}
func (T *recipeWithConns) currentScale(pool *Pool) int {
+ if T.removed {
+ return 0
+ }
+
i := 0
for j := 0; j < len(T.conns); j++ {
if pool.raw.GetServer(T.conns[j]) != nil {
@@ -122,14 +131,17 @@ func (T *recipeWithConns) Scale(pool *Pool, amount int) int {
T.mu.Lock()
defer T.mu.Unlock()
+ if T.removed {
+ return amount
+ }
currentScale := T.currentScale(pool)
return T.scale(pool, currentScale, amount)
}
-func (T *recipeWithConns) SetScale(pool *Pool, scale int) {
- T.mu.Lock()
- defer T.mu.Unlock()
-
+func (T *recipeWithConns) setScale(pool *Pool, scale int) {
+ if T.removed {
+ return
+ }
target := maths.Clamp(scale, T.recipe.GetMinConnections(), T.recipe.GetMaxConnections())
currentScale := T.currentScale(pool)
target -= currentScale
@@ -137,14 +149,27 @@ func (T *recipeWithConns) SetScale(pool *Pool, scale int) {
T.scale(pool, currentScale, target)
}
+func (T *recipeWithConns) SetScale(pool *Pool, scale int) {
+ T.mu.Lock()
+ defer T.mu.Unlock()
+
+ T.setScale(pool, scale)
+}
+
func (T *recipeWithConns) Added(pool *Pool) {
- T.SetScale(pool, 0)
+ T.mu.Lock()
+ defer T.mu.Unlock()
+
+ T.removed = false
+ T.setScale(pool, 0)
}
func (T *recipeWithConns) Removed(pool *Pool) {
T.mu.Lock()
defer T.mu.Unlock()
+ T.removed = true
+
for _, conn := range T.conns {
pool.raw.RemoveServer(conn)
}
@@ -186,23 +211,23 @@ func (T *Pool) Serve(client zap.ReadWriter) {
func (T *Pool) CurrentScale() int {
T.mu.Lock()
- recipes := make([]string, 0, len(T.recipes))
- for recipe := range T.recipes {
+ recipes := make([]*recipeWithConns, 0, len(T.recipes))
+ for _, recipe := range T.recipes {
recipes = append(recipes, recipe)
}
T.mu.Unlock()
scale := 0
for _, recipe := range recipes {
- scale += T.recipes[recipe].CurrentScale(T)
+ scale += recipe.CurrentScale(T)
}
return scale
}
func (T *Pool) Scale(amount int) {
T.mu.Lock()
- recipes := make([]string, 0, len(T.recipes))
- for recipe := range T.recipes {
+ recipes := make([]*recipeWithConns, 0, len(T.recipes))
+ for _, recipe := range T.recipes {
recipes = append(recipes, recipe)
}
T.mu.Unlock()
@@ -213,13 +238,13 @@ outer:
for i := 0; i < len(recipes); i++ {
recipe := recipes[i]
if amount > 0 {
- if T.recipes[recipe].Scale(T, 1) == 0 {
+ if recipe.Scale(T, 1) == 0 {
amount--
recipes[j] = recipes[i]
j++
}
} else if amount < 0 {
- if T.recipes[recipe].Scale(T, -1) == 0 {
+ if recipe.Scale(T, -1) == 0 {
amount++
recipes[j] = recipes[i]
j++
--
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