From caa6cb32801ea0875040877674084983049303ac Mon Sep 17 00:00:00 2001
From: Marc Barry <4965634+marc-barry@users.noreply.github.com>
Date: Fri, 10 Nov 2023 12:14:14 -0500
Subject: [PATCH] Exit and error if a domain lookup for TO_DOMAIN fails.

---
 docker-entrypoint.sh | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/docker-entrypoint.sh b/docker-entrypoint.sh
index 99da509..e8b1c2e 100755
--- a/docker-entrypoint.sh
+++ b/docker-entrypoint.sh
@@ -2,8 +2,23 @@
 
 set -e
 
+# Function to resolve domain to IP
+resolve_domain_to_ip() {
+    local domain=$1
+    local ip
+
+    ip=$(dig +short "$domain" | head -n 1)
+    if [[ -z "$ip" ]]; then
+        echo "Error: Failed to resolve domain $domain"
+        exit 1
+    fi
+
+    echo "$ip"
+}
+
+# If provided resolve TO_DOMAIN to IP and set it to TO_ADDR
 if [[ -n "$TO_DOMAIN" ]]; then
-    TO_ADDR=$(dig +short "$TO_DOMAIN" | head -n 1)
+    TO_ADDR=$(resolve_domain_to_ip "$TO_DOMAIN")
 fi
 
 # Default values for ACCEPT_UIDS and ACCEPT_GIDS