fatal dep error

src/dns.ts

@@ -5,6 +5,7 @@ import { watch } from "fs"
 import { apps } from "./webapp"
 import { expectDir } from "./utils"
 import { NOSE_WWW } from "./config"
+import { expectShellCmd } from "./utils"
 
 export const dnsEntries: Record<string, any> = {}
 
@@ -17,6 +18,8 @@ let dnsInit = false
 
 export async function initDNS() {
     if (process.env.NODE_ENV !== "production") return
+    if (!await expectShellCmd("avahi-publish")) return
+
     dnsInit = true
 
     startWatcher()

src/utils.tsx

@@ -1,6 +1,7 @@
 ////
 // Shell utilities and helper functions.
 
+import { $ } from "bun"
 import { statSync } from "fs"
 import { setFatal } from "./fatal"
 import { stat } from "fs/promises"
@@ -16,7 +17,7 @@ export function untilde(path: string): string {
     return path.replace("~", `/${prefix}/${process.env.USER}`)
 }
 
-// End the process with an instructive error if a directory doesn't exist.
+// Cause a fatal error if a directory doesn't exist.
 export function expectDir(path: string): boolean {
     if (!isDir(path)) {
         setFatal(`Missing critical directory: ${path}`)
@@ -26,6 +27,18 @@ export function expectDir(path: string): boolean {
     return true
 }
 
+// Cause a fatal error if a system binary doesn't exist.
+export async function expectShellCmd(cmd: string): Promise<boolean> {
+    try {
+        await $`which ${cmd}`
+        console.log("WHICH", cmd)
+        return true
+    } catch {
+        setFatal(`Missing critical dependency: avahi-publish`)
+        return false
+    }
+}
+
 // Is the given `path` a file?
 export function isFile(path: string): boolean {
     try {