Fix certificate generation failure when SSL_ALT_NAME is empty

Co-Authored-By: Ryo Kobayashi <cuba6vst@gmail.com>

Author: devin-ai-integration[bot]

nginx/generate-ssl-cert.sh

@@ -9,7 +9,12 @@ SAN=$SSL_ALT_NAME
 if [ -f $KEY ] && [ -f $CERT ]; then
     echo "$ME: Server certificate already exists, do nothing."
 else
-    openssl req -x509 -newkey rsa:2048 -keyout $KEY \
-        -out $CERT -sha256 -days 3650 -nodes -subj "/CN=$CN" -addext "subjectAltName = $SAN"
+    if [ -n "$SAN" ]; then
+        openssl req -x509 -newkey rsa:2048 -keyout $KEY \
+            -out $CERT -sha256 -days 3650 -nodes -subj "/CN=$CN" -addext "subjectAltName = $SAN"
+    else
+        openssl req -x509 -newkey rsa:2048 -keyout $KEY \
+            -out $CERT -sha256 -days 3650 -nodes -subj "/CN=$CN"
+    fi
     echo "$ME: Server certificate has been generated."
 fi