Use Umbrel DNS for Datum polling

docker-compose.yml

@@ -1,7 +1,7 @@
 # gashboard — deploy as a Portainer Stack on the same Umbrel host that runs Datum.
 #
-# Uses the Docker socket to discover Datum's current IP on Umbrel's shared
-# Docker network, avoiding stale hard-coded container IPs.
+# Joins Umbrel's shared Docker network so the API can reach Datum through
+# Docker DNS instead of a changing container IP.
 
 services:
   gashboard:
@@ -21,11 +21,9 @@ services:
       PORT: "1337"
       LOG_LEVEL: "${LOG_LEVEL:-info}"
       CORS_ORIGIN: "${CORS_ORIGIN:-}"
-      # Fallback URL. With DATUM_DOCKER_* set below, the API resolves Datum's
-      # current container IP before polling.
-      DATUM_URL: "${DATUM_URL:-http://datum_datum_1:21000}"
-      DATUM_DOCKER_CONTAINER: "${DATUM_DOCKER_CONTAINER:-datum_datum_1}"
-      DATUM_DOCKER_NETWORK: "${DATUM_DOCKER_NETWORK:-umbrel_main_network}"
+      # Datum's service alias on Umbrel's shared app network. Override this if
+      # your Umbrel install exposes a different DNS name.
+      DATUM_URL: "${DATUM_URL:-http://datum:21000}"
       DATUM_ADMIN_USER: "${DATUM_ADMIN_USER:-admin}"
       DATUM_ADMIN_PASSWORD: "${DATUM_ADMIN_PASSWORD?must be set}"
       DATUM_POLL_INTERVAL_MS: "${DATUM_POLL_INTERVAL_MS:-5000}"
@@ -33,13 +31,17 @@ services:
       NOSTR_ALLOWED_NPUBS: "${NOSTR_ALLOWED_NPUBS?must be set}"
       JWT_SECRET: "${JWT_SECRET?must be set}"
       JWT_TTL_SECONDS: "${JWT_TTL_SECONDS:-86400}"
-    network_mode: host
-    user: "0:0"
-    volumes:
-      - /var/run/docker.sock:/var/run/docker.sock:ro
+    ports:
+      - "${PORT:-1337}:1337"
+    networks:
+      - umbrel_main_network
     healthcheck:
       test: ["CMD", "wget", "-qO-", "http://127.0.0.1:1337/healthz"]
       interval: 30s
       timeout: 5s
       retries: 3
       start_period: 15s
+
+networks:
+  umbrel_main_network:
+    external: true