Stabilize Datum container networking

docker-compose.yml

@@ -1,10 +1,7 @@
-version: "3.9"
-
 # gashboard — deploy as a Portainer Stack on the same Umbrel host that runs Datum.
 #
-# Umbrel's Portainer setup cannot reliably resolve Umbrel app container names
-# from repository stacks. Use host networking and point DATUM_URL at Datum's
-# current container IP on umbrel_main_network.
+# Join Umbrel's shared Docker network so the API can reach Datum by container
+# DNS name instead of a changing container IP.
 
 services:
   gashboard:
@@ -24,10 +21,9 @@ services:
       PORT: "1337"
       LOG_LEVEL: "${LOG_LEVEL:-info}"
       CORS_ORIGIN: "${CORS_ORIGIN:-}"
-      # Reach the Datum gateway container directly. Refresh this IP if Umbrel
-      # recreates Datum:
-      # docker inspect -f '{{.NetworkSettings.Networks.umbrel_main_network.IPAddress}}' datum_datum_1
-      DATUM_URL: "${DATUM_URL?must be set, e.g. http://10.21.0.11:21000}"
+      # Reach the Datum gateway container through Docker DNS on Umbrel's shared
+      # network. This avoids hard-coding Datum's changing container IP.
+      DATUM_URL: "${DATUM_URL:-http://datum_datum_1:21000}"
       DATUM_ADMIN_USER: "${DATUM_ADMIN_USER:-admin}"
       DATUM_ADMIN_PASSWORD: "${DATUM_ADMIN_PASSWORD?must be set}"
       DATUM_POLL_INTERVAL_MS: "${DATUM_POLL_INTERVAL_MS:-5000}"
@@ -35,10 +31,17 @@ services:
       NOSTR_ALLOWED_NPUBS: "${NOSTR_ALLOWED_NPUBS?must be set}"
       JWT_SECRET: "${JWT_SECRET?must be set}"
       JWT_TTL_SECONDS: "${JWT_TTL_SECONDS:-86400}"
-    network_mode: host
+    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