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

gateway/src/cli.ts

@@ -4,14 +4,17 @@
 
 import { loadConfig } from "./config.ts";
 import { openDb } from "./db.ts";
+import { hostUrls } from "./hub.ts";
 import { ORCHESTRATION_PROTOCOL_VERSION, type EnvironmentDescriptor } from "./t3/types.ts";
 
 const USAGE = `wristcode <command>
 
-  host add <url> <pairing-credential> [--label <name>]
+  host add <url> <pairing-credential> [--label <name>] [--alt-url <url>]...
       Connect a T3 Code server. Make the credential on that host with:
       t3 auth pairing create --scope orchestration:read --scope orchestration:operate --label "WristCode gateway"
       Run it again with a fresh credential to renew the gateway's token.
+      --alt-url adds a fallback route to the same server, such as a VPN address, tried in order
+      when <url> does not answer. Repeat it for more.
   host list
   host remove <id or label>
   pair
@@ -39,7 +42,7 @@ async function run() {
       return hostAdd(rest);
     case "host list":
       for (const host of db.hosts.list()) {
-        console.log(`${host.label}\t${host.url}\t${host.id}\ttoken expires ${host.token_expires_at ?? "unknown"}`);
+        console.log(`${host.label}\t${hostUrls(host).join(" ")}\t${host.id}\ttoken expires ${host.token_expires_at ?? "unknown"}`);
       }
       return;
     case "host remove":
@@ -69,9 +72,16 @@ async function run() {
 
 /** Exchanges a T3 pairing credential for a bearer session and saves the host. */
 async function hostAdd(args: string[]) {
-  const labelFlag = args.indexOf("--label");
-  const label = labelFlag === -1 ? undefined : args[labelFlag + 1];
-  const [rawUrl, credential] = args.filter((_, index) => labelFlag === -1 || (index !== labelFlag && index !== labelFlag + 1));
+  const positional: string[] = [];
+  const altUrls: string[] = [];
+  let label: string | undefined;
+  for (let index = 0; index < args.length; index++) {
+    const arg = args[index]!;
+    if (arg === "--label") label = args[++index];
+    else if (arg === "--alt-url") altUrls.push(new URL(args[++index] ?? "").origin);
+    else positional.push(arg);
+  }
+  const [rawUrl, credential] = positional;
   if (!rawUrl || !credential) throw new Error(USAGE);
   const url = new URL(rawUrl).origin;
 
@@ -104,6 +114,7 @@ async function hostAdd(args: string[]) {
     id: descriptor.environmentId,
     label: label ?? descriptor.label,
     url,
+    alt_urls: altUrls.length > 0 ? JSON.stringify(altUrls) : null,
     environment_id: descriptor.environmentId,
     token: token.access_token,
     token_expires_at: token.expires_in ? new Date(Date.now() + token.expires_in * 1000).toISOString() : null,