Gateway: fallback routes per host, for the laptop's VPN address

gateway/src/db.ts

@@ -8,6 +8,8 @@ export interface HostRow {
   id: string;
   label: string;
   url: string;
+  /** Fallback routes to the same server, as a JSON array, tried in order after `url`. */
+  alt_urls: string | null;
   environment_id: string;
   token: string;
   token_expires_at: string | null;
@@ -61,17 +63,19 @@ export function openDb(path: string) {
   db.run("pragma journal_mode = wal");
   db.run("pragma busy_timeout = 5000");
   db.run(SCHEMA);
+  const hostColumns = db.query<{ name: string }, []>("pragma table_info(hosts)").all().map((column) => column.name);
+  if (!hostColumns.includes("alt_urls")) db.run("alter table hosts add column alt_urls text");
 
   return {
     hosts: {
       list: () => db.query<HostRow, []>("select * from hosts order by created_at").all(),
       upsert(host: Omit<HostRow, "created_at">) {
         db.query(
-          `insert into hosts (id, label, url, environment_id, token, token_expires_at, created_at)
-           values ($id, $label, $url, $environment_id, $token, $token_expires_at, $created_at)
+          `insert into hosts (id, label, url, alt_urls, environment_id, token, token_expires_at, created_at)
+           values ($id, $label, $url, $alt_urls, $environment_id, $token, $token_expires_at, $created_at)
            on conflict(environment_id) do update set
-             label = excluded.label, url = excluded.url, token = excluded.token,
-             token_expires_at = excluded.token_expires_at`,
+             label = excluded.label, url = excluded.url, alt_urls = excluded.alt_urls,
+             token = excluded.token, token_expires_at = excluded.token_expires_at`,
         ).run({ ...host, created_at: now() });
       },
       remove: (idOrLabel: string) =>