fix: recover mempool frontend after backend address changes

2026-09-15 02:49:06 -04:00
parent 700d39c425
commit b35409ca74
9 changed files with 244 additions and 149 deletions
@@ -0,0 +1,29 @@
+# Mempool frontend DNS recovery
+
+The stock v3.3.1 nginx configuration resolves `mempool-api` only when workers
+start. Recreating the backend can change its Podman address while the frontend
+continues to serve its static page, leaving all API/WebSocket requests offline.
+
+Build and test the derived image before publishing:
+
+```sh
+podman build --pull=never -t source.archipelago-foundation.org/lfg2025/mempool-frontend:v3.3.1-archy1 docker/mempool-frontend
+python3 scripts/test-mempool-dns-recovery.py
+```
+
+The base is pinned by digest. The wrapper preserves upstream runtime options,
+then repairs all four local API/WebSocket routes after placeholder rendering.
+DNS is cached for five seconds using the container network resolver. Explicit
+rewrites preserve API prefixes and query arguments; backend absence does not
+prevent nginx startup. An unexpected upstream configuration fails startup
+instead of silently omitting the fix.
+
+Use an Archipelago-specific image tag. Do not replace it with a stock upstream
+mirror when updating mempool. Every upstream update must rebuild this wrapper
+and pass the recovery test (backend absent, changed IP, HTTP and WebSocket
+mapping, repeated repair, and frontend restart).
+
+Publish the tested image before publishing the signed app catalog. Both the
+mempool umbrella image mapping and the archy-mempool-web embedded manifest must
+point at the patched image. Keep scripts/image-versions.sh in sync. The frontend
+health check must reach `/api/v1/backend-info` through nginx, not only `/`.