try to show error page on fatal errors

src/commands.ts

@@ -56,7 +56,7 @@ export async function loadCommandModule(cmd: string) {
 let sysCmdWatcher
 let usrCmdWatcher
 function startWatchers() {
-  expectDir(NOSE_BIN)
+  if (!expectDir(NOSE_BIN)) return
 
   sysCmdWatcher = watch(NOSE_SYS_BIN, async (event, filename) =>
     sendAll({ type: "commands", data: await commands() })

src/dns.ts

@@ -44,7 +44,7 @@ export function publishAppDNS(app: string) {
 
 let wwwWatcher
 function startWatcher() {
-    expectDir(NOSE_WWW)
+    if (!expectDir(NOSE_WWW)) return
 
     wwwWatcher = watch(NOSE_WWW, (event, filename) => {
         const www = apps()

src/fatal.ts

@@ -0,0 +1,10 @@
+////
+// We want to show a blue screen of death if NOSE has a fatal error.
+
+export let fatal: string | undefined
+
+export function setFatal(error: string) {
+    console.error(error)
+    if (!fatal)
+        fatal = error
+}

src/html/error.tsx

@@ -0,0 +1,60 @@
+import type { FC } from "hono/jsx"
+import { css, js } from "../helpers"
+
+export const Error: FC = async ({ error }) => (
+    <>
+        {css`
+            :root {
+                --letterbox: #CC8800;
+                --text: #FFBF40;
+                --bg: #201600;
+            }
+            * { color: var(--text); text-align: center; }
+            html { background: var(--letterbox); }
+            #content { background-color: var(--bg); }
+
+            h1 { max-width: 38%; margin: 0 auto; margin-top: 100px; }
+            h2 { max-width: 80%; margin: 0 auto; margin-top: 10px; }
+            p { max-width: 90%; margin: 0 auto; margin-top: 150px; }
+
+            .restart { max-width: 35%;  }
+            .restart button {
+                font-size: 30px;
+                background: var(--letterbox);
+                color: var(--red);
+            }
+
+            h1 { animation: glow 3s ease-in-out infinite alternate; }
+
+            @keyframes glow {
+                0% {
+                    text-shadow: none;
+                }
+                100% {
+                    text-shadow:
+                        0 0 2px #FFAA33,
+                        0 0 4px #FF8800,
+                        0 0 6px #FF6600;
+                }
+            }
+
+        `}
+
+        {js`
+            window.addEventListener("click", async e => {
+                if (!e.target || !e.target.matches("button")) return
+                e.target.textContent = "[RESTARTING...]"
+                await fetch("/cmd/restart")
+                setTimeout(() => window.location.reload(), 3000)
+            })
+        `}
+
+        <h1>Fatal Error</h1>
+        <h2>NOSE failed to start properly.</h2>
+        <br />
+        <p>{error}</p>
+        <p class="restart">
+            <button>[RESTART]</button>
+        </p>
+    </>
+)

src/nosedir.ts

@@ -3,12 +3,13 @@
 
 import { $ } from "bun"
 import { NOSE_DIR } from "./config"
-import { isDir } from "./utils"
+import { expectDir } from "./utils"
 
 // Make NOSE_DIR if it doesn't exist
 export async function initNoseDir() {
-  if (isDir(NOSE_DIR)) return
+  if (expectDir(NOSE_DIR)) return
 
   await $`cp -r ./nose ${NOSE_DIR}`
+  expectDir(NOSE_DIR)
 }
 

src/server.tsx

@@ -8,17 +8,20 @@ import color from "kleur"
 
 import type { Message } from "./shared/types"
 import { NOSE_ICON, NOSE_BIN, NOSE_WWW, NOSE_DATA, NOSE_DIR } from "./config"
-import { transpile, isFile, tilde } from "./utils"
+import { transpile, isFile, tilde, isDir } from "./utils"
 import { serveApp } from "./webapp"
-import { initDNS } from "./dns"
 import { commands, commandPath, loadCommandModule } from "./commands"
 import { runCommandFn } from "./shell"
 import { send, addWebsocket, removeWebsocket, closeWebsockets } from "./websocket"
+import { initSneakers, disconnectSneakers } from "./sneaker"
+import { dispatchMessage } from "./dispatch"
+import { fatal } from "./fatal"
 
 import { Layout } from "./html/layout"
 import { Terminal } from "./html/terminal"
-import { dispatchMessage } from "./dispatch"
-import { initSneakers, disconnectSneakers } from "./sneaker"
+import { Error } from "./html/error"
+
+import { initDNS } from "./dns"
 import { initNoseDir } from "./nosedir"
 import { initCommands } from "./commands"
 
@@ -43,6 +46,16 @@ app.use("*", async (c, next) => {
     console.log(fn(`${c.res.status} ${c.req.method} ${c.req.url} (${end - start}ms)`))
 })
 
+app.use("*", async (c, next) => {
+    const error = fatal ? fatal : !isDir(NOSE_DIR) ? `NOSE_DIR doesn't exist: ${NOSE_DIR}` : undefined
+
+    if (!error || (["/cmd/restart", "/cmd/reboot"].includes(c.req.path))) {
+        await next()
+    } else {
+        return c.html(<Layout><Error error={error} /></Layout>, 500)
+    }
+})
+
 app.on("GET", ["/js/:path{.+}", "/shared/:path{.+}"], async c => {
     let path = "./src/" + c.req.path.replace("..", ".")
 

src/utils.tsx

@@ -2,7 +2,7 @@
 // Shell utilities and helper functions.
 
 import { statSync } from "fs"
-import { basename } from "path"
+import { setFatal } from "./fatal"
 import { stat } from "fs/promises"
 
 // Convert /Users/$USER or /home/$USER to ~ for simplicity
@@ -17,11 +17,13 @@ export function untilde(path: string): string {
 }
 
 // End the process with an instructive error if a directory doesn't exist.
-export function expectDir(path: string) {
+export function expectDir(path: string): boolean {
     if (!isDir(path)) {
-        console.error(`No ${basename(path)} directory detected.`)
-        process.exit(1)
+        setFatal(`Missing critical directory: ${path}`)
+        return false
     }
+
+    return true
 }
 
 // Is the given `path` a file?