From 0d1fbef75109d807b64d2fae8b5939a95c276fab Mon Sep 17 00:00:00 2001
From: Harshavardhana <harsha@minio.io>
Date: Wed, 30 Aug 2023 07:27:45 -0700
Subject: [PATCH] fix: a possible crash in event target Close() (#17948)

these are possible crashes when the configured
target is still in init() state and never finished
- however a delete config was initiated.
---
 internal/event/target/mqtt.go       | 4 +++-
 internal/event/target/mysql.go      | 6 +++++-
 internal/event/target/postgresql.go | 6 +++++-
 internal/event/target/redis.go      | 5 ++++-
 4 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/internal/event/target/mqtt.go b/internal/event/target/mqtt.go
index 171486e25..aa2a2475e 100644
--- a/internal/event/target/mqtt.go
+++ b/internal/event/target/mqtt.go
@@ -219,7 +219,9 @@ func (target *MQTTTarget) Save(eventData event.Event) error {
 
 // Close - does nothing and available for interface compatibility.
 func (target *MQTTTarget) Close() error {
-	target.client.Disconnect(100)
+	if target.client != nil {
+		target.client.Disconnect(100)
+	}
 	close(target.quitCh)
 	return nil
 }
diff --git a/internal/event/target/mysql.go b/internal/event/target/mysql.go
index bc6c53c84..48966f4b9 100644
--- a/internal/event/target/mysql.go
+++ b/internal/event/target/mysql.go
@@ -312,7 +312,11 @@ func (target *MySQLTarget) Close() error {
 		_ = target.insertStmt.Close()
 	}
 
-	return target.db.Close()
+	if target.db != nil {
+		return target.db.Close()
+	}
+
+	return nil
 }
 
 // Executes the table creation statements.
diff --git a/internal/event/target/postgresql.go b/internal/event/target/postgresql.go
index 132b6d40c..736bafe33 100644
--- a/internal/event/target/postgresql.go
+++ b/internal/event/target/postgresql.go
@@ -308,7 +308,11 @@ func (target *PostgreSQLTarget) Close() error {
 		_ = target.insertStmt.Close()
 	}
 
-	return target.db.Close()
+	if target.db != nil {
+		target.db.Close()
+	}
+
+	return nil
 }
 
 // Executes the table creation statements.
diff --git a/internal/event/target/redis.go b/internal/event/target/redis.go
index ad8d2a917..cc483404c 100644
--- a/internal/event/target/redis.go
+++ b/internal/event/target/redis.go
@@ -273,7 +273,10 @@ func (target *RedisTarget) SendFromStore(eventKey string) error {
 // Close - releases the resources used by the pool.
 func (target *RedisTarget) Close() error {
 	close(target.quitCh)
-	return target.pool.Close()
+	if target.pool != nil {
+		return target.pool.Close()
+	}
+	return nil
 }
 
 func (target *RedisTarget) init() error {