From 2bbb89c53ff29700aa29f979f2d03dbf7e114379 Mon Sep 17 00:00:00 2001
From: Dorian <dorian@Dorians-MacBook-Air.local>
Date: Sat, 9 May 2026 16:26:18 +0100
Subject: [PATCH] Stabilize Datum container networking

---
 .env.example                 |  8 +++-----
 README.md                    | 13 +++++++------
 apps/api/src/datum/poller.ts |  2 +-
 docker-compose.yml           | 23 +++++++++++++----------
 4 files changed, 24 insertions(+), 22 deletions(-)

diff --git a/.env.example b/.env.example
index 9e80cc9..1a96368 100644
--- a/.env.example
+++ b/.env.example
@@ -13,11 +13,9 @@ LOG_LEVEL=info
 # STATIC_DIR=
 
 # ---- Datum gateway (the Umbrel app we're polling) ----
-# Umbrel/Portainer stacks cannot reliably resolve Datum's container name.
-# Use Datum's current IP on umbrel_main_network and refresh it if Umbrel
-# recreates the Datum container:
-# docker inspect -f '{{.NetworkSettings.Networks.umbrel_main_network.IPAddress}}' datum_datum_1
-DATUM_URL=http://10.21.0.11:21000
+# Use Docker DNS on umbrel_main_network so Datum can be recreated without
+# changing a stale container IP.
+DATUM_URL=http://datum_datum_1:21000
 DATUM_ADMIN_USER=admin
 DATUM_ADMIN_PASSWORD=
 # How often to scrape /clients (ms). Datum updates per-worker hashrate every
diff --git a/README.md b/README.md
index e203dca..98d4498 100644
--- a/README.md
+++ b/README.md
@@ -46,12 +46,13 @@ Allowlist of npubs is set via `NOSTR_ALLOWED_NPUBS`. Anything else is rejected b
    - Repository URL: `https://git.tx1138.com/lfg2025/gashboard`
    - Compose path: `docker-compose.yml`
    - Add env vars (see `.env.example`)
-   - Set `DATUM_URL` to Datum's current container IP:
-     ```bash
-     docker inspect -f '{{.NetworkSettings.Networks.umbrel_main_network.IPAddress}}' datum_datum_1
-     ```
-   - Use it as `DATUM_URL=http://<that-ip>:21000`.
-   - If Datum/Umbrel recreates the container, refresh this IP in Portainer and redeploy.
+   - Remove any old `DATUM_URL=http://10.21...` value from the stack env vars.
+     Leave `DATUM_URL` unset unless your Datum container name is different. By
+     default the stack uses `http://datum_datum_1:21000` on Umbrel's
+     `umbrel_main_network`, so Datum can be recreated without changing a stale
+     IP address.
+   - If your Umbrel install uses a different Datum container name, set
+     `DATUM_URL=http://<container-name>:21000`.
 
 4. Open the dashboard, log in with one of the allowed npubs, watch your boards lose at hashing in style.
 
diff --git a/apps/api/src/datum/poller.ts b/apps/api/src/datum/poller.ts
index ad5c8b7..a6265d6 100644
--- a/apps/api/src/datum/poller.ts
+++ b/apps/api/src/datum/poller.ts
@@ -64,7 +64,7 @@ function formatErr(err: unknown): string {
       const datumHost = new URL(config.datum.url).hostname;
       const hint =
         hostname === datumHost
-          ? "; check DATUM_NETWORK or set DATUM_URL to a hostname/IP reachable from the gashboard API container"
+          ? "; make sure gashboard is attached to Umbrel's Docker network or set DATUM_URL to a hostname/IP reachable from the API container"
           : "";
       return `${err.message}: DNS could not resolve ${hostname} (${code})${hint}`;
     }
diff --git a/docker-compose.yml b/docker-compose.yml
index b0cc00c..bfc5901 100644
--- a/docker-compose.yml
+++ b/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