Add docker-ip-addr-manager initial app

Apps/docker-ip-addr-manager/backend/app/config.py

@@ -0,0 +1,21 @@
+from __future__ import annotations
+
+from dataclasses import dataclass
+import os
+
+
+@dataclass(frozen=True)
+class Settings:
+    state_file: str
+    docker_api_url: str
+    docker_timeout_seconds: float
+    app_port: int
+
+
+def get_settings() -> Settings:
+    return Settings(
+        state_file=os.getenv("STATE_FILE", "/data/entries.json"),
+        docker_api_url=os.getenv("DOCKER_API_URL", "unix:///var/run/docker.sock"),
+        docker_timeout_seconds=float(os.getenv("DOCKER_TIMEOUT_SECONDS", "3")),
+        app_port=int(os.getenv("APP_PORT", "31810")),
+    )