From 2c43767bbe5573db5df158cb6f0023a53d8ecb1c Mon Sep 17 00:00:00 2001
From: "Grapette.L" <90967079+Lesereingrape@users.noreply.github.com>
Date: Thu, 24 Sep 2026 15:56:38 +0800
Subject: [PATCH] fix(gateway): treat a blank GATEWAY_HOST/GATEWAY_PORT as
 unset (#5801)
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os.getenv's default only covers an unset variable, so `docker run -e
GATEWAY_PORT=` — or `GATEWAY_PORT=${PORT}` with PORT unset — reached
int("") and aborted the create_app() import that both entry points run.
Blank now falls back to the declared default, while "0" stays a real port.
---
 backend/app/gateway/config.py             |  5 +++--
 backend/tests/test_gateway_docs_toggle.py | 25 +++++++++++++++++++++++
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/backend/app/gateway/config.py b/backend/app/gateway/config.py
index 06a7d5b1ac..7f9bb02c25 100644
--- a/backend/app/gateway/config.py
+++ b/backend/app/gateway/config.py
@@ -19,8 +19,9 @@ def get_gateway_config() -> GatewayConfig:
     global _gateway_config
     if _gateway_config is None:
         _gateway_config = GatewayConfig(
-            host=os.getenv("GATEWAY_HOST", "0.0.0.0"),
-            port=int(os.getenv("GATEWAY_PORT", "8001")),
+            # A blank means "unset" (`-e GATEWAY_PORT=`, or `${PORT}` with PORT unset); int("") would abort the create_app() import
+            host=os.getenv("GATEWAY_HOST") or "0.0.0.0",
+            port=int(os.getenv("GATEWAY_PORT") or "8001"),
             enable_docs=os.getenv("GATEWAY_ENABLE_DOCS", "true").lower() == "true",
         )
     return _gateway_config
diff --git a/backend/tests/test_gateway_docs_toggle.py b/backend/tests/test_gateway_docs_toggle.py
index 986370286a..24a7c7d02b 100644
--- a/backend/tests/test_gateway_docs_toggle.py
+++ b/backend/tests/test_gateway_docs_toggle.py
@@ -78,6 +78,31 @@ def test_enable_docs_unexpected_value_disables():
             assert config.enable_docs is False, f"Expected False for GATEWAY_ENABLE_DOCS={value}"
 
 
+def test_blank_host_and_port_fall_back_to_defaults():
+    """A blank GATEWAY_HOST/GATEWAY_PORT means unset, not a crash or an empty bind address.
+
+    ``docker run -e GATEWAY_PORT=`` and ``environment: [GATEWAY_PORT=${PORT}]`` with PORT
+    unset both reach us as an empty string, and create_app() reads this at import time.
+    """
+    with patch.dict(os.environ, {"GATEWAY_HOST": "", "GATEWAY_PORT": ""}):
+        _reset_gateway_config()
+        from app.gateway.config import get_gateway_config
+
+        config = get_gateway_config()
+        assert config.port == 8001
+        assert config.host == "0.0.0.0"
+
+
+def test_zero_port_is_not_treated_as_unset():
+    """GATEWAY_PORT=0 asks the OS for a free port, so it must survive the blank fallback."""
+    with patch.dict(os.environ, {"GATEWAY_PORT": "0"}):
+        _reset_gateway_config()
+        from app.gateway.config import get_gateway_config
+
+        config = get_gateway_config()
+        assert config.port == 0
+
+
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