Allow emulators to work offline (MOTD fail)

src/fetchMOTD.ts

@@ -5,6 +5,7 @@ import { Client } from "./apiv2";
 import { configstore } from "./configstore";
 import { realtimeOrigin } from "./api";
 import * as utils from "./utils";
+import { FirebaseError } from "./error";
 
 const pkg = require("../package.json"); // eslint-disable-line @typescript-eslint/no-var-requires
 
@@ -43,10 +44,26 @@ export function fetchMOTD(): void {
   } else {
     const origin = utils.addSubdomain(realtimeOrigin, "firebase-public");
     const c = new Client({ urlPrefix: origin, auth: false });
-    c.get("/cli.json").then((res) => {
-      motd = Object.assign({}, res.body);
-      configstore.set("motd", motd);
-      configstore.set("motd.fetched", Date.now());
-    });
+    c.get("/cli.json")
+      .then((res) => {
+        motd = Object.assign({}, res.body);
+        configstore.set("motd", motd);
+        configstore.set("motd.fetched", Date.now());
+      })
+      .catch((err) => {
+        const args = process.argv.slice(2);
+
+        if (args.findIndex((arg) => arg.startsWith("emulators:")) === -1) {
+          throw new FirebaseError(
+            "Unable to fetch the CLI version check configuration. Make sure that you are online and try again.",
+            { original: err }
+          );
+        }
+
+        utils.logLabeledWarning(
+          "emulators",
+          "Unable to fetch the CLI version check configuration, emulator functionality may be incorrect."
+        );
+      });
   }
 }