swarm: nats and matrix OIDC fetch units fail until the secret is published

An unpublished or empty secret in swarm-bao-nats-auth-oidc and
swarm-bao-matrix-oidc now exits 1 instead of 0, the shape
swarm-bao-forwarder-oidc already uses. storeRetry then re-fetches every 30s
until swarm-secret-publish has written the secret, and refresh_consumer
starts the responder / tuwunel once the file lands. Before, a fresh swarm's
first fetch found nothing, exited 0, and neither consumer started until the
unit was restarted by hand.

nix/host-modules/hive-matrix.nix

@@ -585,9 +585,9 @@ in
 
     # The homeserver's OIDC client secret, out of the swarm secret store under
     # matrix-ctl's leaf — the one route, wherever authelia runs. Same shape as
-    # ./swarm-grafana.nix's `swarm-bao-grafana-oidc`: a login that fails
-    # loudly, since a retry fixes every state it fails on, then a read that
-    # degrades quietly, since an absent value is "not published yet".
+    # ./swarm-bao.nix's `swarm-bao-forwarder-oidc`: the login and the read both
+    # fail loudly, and `storeRetry` retries until the publisher on authelia's
+    # host has written the secret, because tuwunel does not start without it.
     #
     # ⚠️ tuwunel requires the file to exist and be non-empty, and its
     # `LoadCredential` source must exist for the unit to start, so a host with
@@ -669,12 +669,12 @@ in
               else
                 echo "bao failed without writing a diagnostic." >&2
               fi
-              exit 0
+              exit 1
             fi
 
             if [ -z "$secret" ]; then
-              echo "swarm-bao returned an empty ${storeSecretPath}; leaving the file as it is." >&2
-              exit 0
+              echo "swarm-bao returned an empty ${storeSecretPath}; the homeserver has no OIDC client secret yet." >&2
+              exit 1
             fi
 
             # Root-owned 0400: tuwunel runs under `DynamicUser`, so there is no

nix/host-modules/swarm-nats.nix

@@ -921,9 +921,10 @@ in
 
     # The responder's OIDC client secret, out of the swarm secret store under
     # the responder's own leaf — the one route, wherever authelia runs. Same
-    # shape as ./swarm-grafana.nix's `swarm-bao-grafana-oidc`: a login that
-    # fails loudly, since a retry fixes every state it fails on, then a read
-    # that degrades quietly, since an absent value is "not published yet".
+    # shape as ./swarm-bao.nix's `swarm-bao-forwarder-oidc`: the login and the
+    # read both fail loudly, and `storeRetry` retries until the publisher on
+    # authelia's host has written the secret, because the responder has no
+    # mode that runs without it.
     #
     # ⚠️ Without the secret the responder does not start (its `LoadCredential`
     # source is missing), and `auth_callout` with no responder refuses every
@@ -1008,12 +1009,12 @@ in
               else
                 echo "bao failed without writing a diagnostic." >&2
               fi
-              exit 0
+              exit 1
             fi
 
             if [ -z "$secret" ]; then
-              echo "swarm-bao returned an empty ${storeSecretPath}; leaving the file as it is." >&2
-              exit 0
+              echo "swarm-bao returned an empty ${storeSecretPath}; the queue responder has no OIDC client secret yet." >&2
+              exit 1
             fi
 
             # Root-owned 0400: `LoadCredential` reads it as root before the

nix/module-eval/matrix-core.nix

@@ -90,6 +90,8 @@ let
         && lib.hasInfix "bao kv get -field=value secret/swarm/services/tuwunel/oidc/client" u.script
         && lib.hasInfix "/var/lib/nixos-containers/hive-matrix/var/lib/tuwunel-oidc/tuwunel.secret" u.script
         && lib.hasInfix "refresh_consumer hive-matrix tuwunel.service" u.script
+        # An unpublished or empty secret fails the unit, so `storeRetry` retries it.
+        && !(lib.hasInfix "exit 0" u.script)
         && lib.elem "container@hive-matrix.service" u.before
         && !(s ? hive-matrix-oidc-secret);
     }

nix/module-eval/nats-authelia.nix

@@ -209,6 +209,8 @@ let
         && lib.hasInfix "bao kv get -field=value secret/swarm/services/swarm-nats/oidc/client" fetch.script
         && lib.hasInfix "/var/lib/nixos-containers/swarm-nats/var/lib/swarm-nats-auth/oidc-client.secret" fetch.script
         && lib.hasInfix "refresh_consumer swarm-nats swarm-nats-auth.service" fetch.script
+        # An unpublished or empty secret fails the unit, so `storeRetry` retries it.
+        && !(lib.hasInfix "exit 0" fetch.script)
         && lib.elem "container@swarm-nats.service" fetch.before
         && !(lib.hasInfix "oidc-client" copy)
         && !(lib.hasInfix "authelia" copy);