modules: wire tool-runtime app credentials as own-secrets

The six modules that run a mesh-<mod> tool-runtime sidecar read an app
credential from an env var the manifest never provided, so the sidecar
crash-looped in the whole-mesh dry-run (e.g. "no Plex token — set
MESH_PLEX_TOKEN"). These are operator-set app secrets, so deliver them the
same way cloudflare-dns delivers its API token: an own-secret file mounted
read-only, with a MESH_<APP>_*_FILE env pointing at the mount, and the
runtime code preferring that file (falling back to the existing env so
nothing regresses).

- plex: own-secret token -> /run/secrets/token, MESH_PLEX_TOKEN_FILE
- bazarr: own-secret api-key -> /run/secrets/api-key, MESH_BAZARR_API_KEY_FILE
- ombi: own-secret api-key -> /run/secrets/api-key, MESH_OMBI_API_KEY_FILE
- home-assistant: own-secret token -> /run/secrets/token, MESH_HOMEASSISTANT_TOKEN_FILE
- nzbget: own-secret password -> /run/secrets/password, MESH_NZBGET_PASSWORD_FILE (URL stays plain env)
- qbittorrent: own-secret password -> /run/secrets/password, MESH_QBITTORRENT_PASSWORD_FILE (URL stays plain env)

The operator now completes each with `secret accept <node> <module> <name> --from <file>`.
tsc passes for all six.

modules/plex/client.ts

@@ -5,6 +5,17 @@
 import { existsSync, readFileSync } from "node:fs";
 import { join } from "node:path";
 
+/** Read a secret the mesh mounted at a file path (an own-secret); absent or unreadable yields
+ *  undefined, so callers can fall back rather than crash. */
+function readSecret(path: string | undefined): string | undefined {
+  if (!path) return undefined;
+  try {
+    return readFileSync(path, "utf8").trim();
+  } catch {
+    return undefined;
+  }
+}
+
 export interface PlexLibrary {
   key: string;
   title: string;
@@ -47,7 +58,9 @@ export class PlexClient {
   static fromEnv(env: NodeJS.ProcessEnv = process.env): PlexClient {
     const url = env.MESH_PLEX_URL ?? `http://127.0.0.1:${env.PLEX_PORT ?? "32400"}`;
     const dataDir = env.MESH_PLEX_DATA_DIR ?? "/var/lib/plex";
-    const token = env.MESH_PLEX_TOKEN ?? PlexClient.detectToken(dataDir);
+    // The operator-provided token is an own-secret the mesh mounts at MESH_PLEX_TOKEN_FILE (delivered
+    // by `secret accept`); prefer it, fall back to a bare env var, then to discovery from the data dir.
+    const token = readSecret(env.MESH_PLEX_TOKEN_FILE) ?? env.MESH_PLEX_TOKEN ?? PlexClient.detectToken(dataDir);
     if (!token) throw new Error("no Plex token — set MESH_PLEX_TOKEN or make the data dir readable");
     return new PlexClient(url, token);
   }

modules/plex/module.json

@@ -13,7 +13,8 @@
     "module.*.download.completed"
   ],
   "own-secrets": {
-    "broker": "/var/lib/mesh/plex/broker"
+    "broker": "/var/lib/mesh/plex/broker",
+    "token": "/var/lib/mesh/plex/token"
   },
   "listens": [
     {
@@ -95,11 +96,13 @@
       "network": "host",
       "volumes": [
         "/var/lib/mesh/plex/broker:/run/secrets/broker:ro",
+        "/var/lib/mesh/plex/token:/run/secrets/token:ro",
         "/services/plex/config:/var/lib/plex/config:ro"
       ],
       "env": {
         "MESH_BROKER_FILE": "/run/secrets/broker",
         "MESH_PLEX_URL": "http://127.0.0.1:32400",
+        "MESH_PLEX_TOKEN_FILE": "/run/secrets/token",
         "MESH_PLEX_DATA_DIR": "/var/lib/plex"
       }
     }