From 73d0ab8b70f22cab78e92b2712cb8fd4da944848 Mon Sep 17 00:00:00 2001
From: Robin <robin.braemer@web.de>
Date: Tue, 22 Aug 2023 12:56:46 +0200
Subject: [PATCH] fix(connect): Ensure Connect instance runs only once

---
 .web/docs/guide/config/reload.md |  9 ++++---
 pkg/gate/connect.go              | 45 ++++++++++++++++++++++++--------
 2 files changed, 39 insertions(+), 15 deletions(-)

diff --git a/.web/docs/guide/config/reload.md b/.web/docs/guide/config/reload.md
index 5f8b40f5..ab0a8be2 100644
--- a/.web/docs/guide/config/reload.md
+++ b/.web/docs/guide/config/reload.md
@@ -1,6 +1,6 @@
 # Auto Config Reload
 
-_Gate watches your file for updates._
+_Gate watches your config file for updates._
 
 ---
 
@@ -36,6 +36,7 @@ This feature is always enabled by default, given that you have a config file.
 
 ## How to disable it
 
-This can not be disabled.
-If you feel like you need to disable it, please [open an issue](
-https://github.com/minekube/gate/issues/new?title=Disable%20auto%20config%20reload&body=I%20want%20to%20disable%20auto%20config%20reload%20because%20...).
+Please note that the auto config reload feature cannot be disabled.
+If you feel a compelling need to do so, please don't hesitate to [open an issue](
+https://github.com/minekube/gate/issues/new?title=Disable%20auto%20config%20reload&body=I%20want%20to%20disable%20auto%20config%20reload%20because%20...)
+on our GitHub repository.
diff --git a/pkg/gate/connect.go b/pkg/gate/connect.go
index 01c13669..591bd1e5 100644
--- a/pkg/gate/connect.go
+++ b/pkg/gate/connect.go
@@ -1,7 +1,10 @@
 package gate
 
 import (
+	"bytes"
 	"context"
+	"crypto/sha1"
+	"encoding/json"
 	"sync"
 
 	"github.com/go-logr/logr"
@@ -26,29 +29,38 @@ func setupConnect(
 		var (
 			mu          sync.Mutex
 			stopConnect context.CancelFunc
-			name        string
+			// keep track of current config hash to avoid unnecessary restarts when config didn't change
+			currentConfigHash []byte
 		)
 		trigger := func(c *config.Config) {
-			cfg := c.Connect
-			if cfg.Enabled && !c.Editions.Java.Enabled {
+			connect := c.Connect
+			if connect.Enabled && !c.Editions.Java.Enabled {
 				log.Info("Connect is only supported for Java edition")
 				return
 			}
 
+			newConfigHash, err := jsonHash(connect)
+			if err != nil {
+				log.Error(err, "error hashing Connect config")
+				return
+			}
+
 			mu.Lock()
 			defer mu.Unlock()
-			if (!cfg.Enabled && stopConnect != nil) ||
-				(cfg.Enabled && (stopConnect == nil || cfg.Name != name)) {
 
-				if stopConnect != nil {
-					stopConnect()
-					stopConnect = nil
-				}
+			// check if config changed
+			if bytes.Equal(newConfigHash, currentConfigHash) {
+				return // no change
 			}
+			currentConfigHash = newConfigHash
 
-			name = cfg.Name
+			// stop current Connect if running
+			if stopConnect != nil {
+				stopConnect()
+				stopConnect = nil
+			}
 
-			runnable, err := connectcfg.New(cfg, instance)
+			runnable, err := connectcfg.New(connect, instance)
 			if err != nil {
 				log.Error(err, "error setting up Connect")
 				return
@@ -58,6 +70,7 @@ func setupConnect(
 			runCtx, stopConnect = context.WithCancel(ctx)
 
 			go func() {
+				defer stopConnect()
 				if err = runnable.Start(runCtx); err != nil {
 					log.Error(err, "error with Connect")
 					return
@@ -76,3 +89,13 @@ func setupConnect(
 		return nil
 	}))
 }
+
+// jsonHash returns the sha1 hash of the JSON representation of v.
+func jsonHash(v any) ([]byte, error) {
+	j, err := json.Marshal(v)
+	if err != nil {
+		return nil, err
+	}
+	h := sha1.Sum(j)
+	return h[:], nil
+}