Fix: stop register-super failing against a running app (fixes #123)

lib/utils/isAppRunning.js

@@ -0,0 +1,22 @@
+import internalApiRequest from './internalApiRequest.js'
+
+/**
+ * Checks whether an app instance is already listening on the configured host/port.
+ *
+ * Any HTTP response means something is serving, including an error status: the probe requests
+ * the API endpoint map, which requires authentication, so an unauthenticated probe is answered
+ * with a 401 rather than a 200. Only a refused connection means nothing is listening.
+ *
+ * @param {Object} options Options to pass to the request
+ * @return {Promise<Boolean>} Whether an app instance is already running
+ */
+export default async function isAppRunning (options = {}) {
+  try {
+    await internalApiRequest('', undefined, { ...options, method: 'GET' })
+  } catch (e) {
+    if (e.statusCode !== undefined) return true
+    if ((e.code ?? e.cause?.code) === 'ECONNREFUSED') return false
+    throw e
+  }
+  return true
+}

lib/utils/registerSuperUser.js

@@ -1,13 +1,11 @@
 import { createInterface } from 'readline'
 import prompts from 'prompts'
 import internalApiRequest from './internalApiRequest.js'
+import isAppRunning from './isAppRunning.js'
 import startApp from './startApp.js'
 
 export default async function registerSuperUser (options = {}) {
-  try {
-    await internalApiRequest('', undefined, { ...options, method: 'GET' })
-  } catch (e) {
-    if ((e.code ?? e.cause?.code) !== 'ECONNREFUSED') throw e
+  if (!await isAppRunning(options)) {
     await startApp(options)
   }
   let email = options.superEmail

tests/isAppRunning.spec.js

@@ -0,0 +1,62 @@
+import { describe, it, mock } from 'node:test'
+import assert from 'node:assert/strict'
+
+let requestError
+
+// mock internalApiRequest before importing isAppRunning
+mock.module('../lib/utils/internalApiRequest.js', {
+  defaultExport: async () => {
+    if (requestError) throw requestError
+  }
+})
+
+const { default: isAppRunning } = await import('../lib/utils/isAppRunning.js')
+
+/** Builds the error internalApiRequest throws for a non-2xx response */
+function httpError (code, statusCode) {
+  const e = new Error(code)
+  e.code = code
+  e.statusCode = statusCode
+  return e
+}
+
+/** Builds the error fetch throws when it can't connect */
+function transportError (code) {
+  const e = new TypeError('fetch failed')
+  e.cause = Object.assign(new Error(code), { code })
+  return e
+}
+
+describe('isAppRunning', () => {
+  it('should return true when the request succeeds', async () => {
+    requestError = undefined
+    assert.equal(await isAppRunning(), true)
+  })
+
+  it('should return true when the app responds with an auth error', async () => {
+    requestError = httpError('MISSING_AUTH_HEADER', 401)
+    assert.equal(await isAppRunning(), true)
+  })
+
+  it('should return true for any other error status', async () => {
+    for (const [code, status] of [['UNAUTHORISED', 403], ['NOT_FOUND', 404], ['SERVER_ERROR', 500]]) {
+      requestError = httpError(code, status)
+      assert.equal(await isAppRunning(), true)
+    }
+  })
+
+  it('should return false when the connection is refused', async () => {
+    requestError = transportError('ECONNREFUSED')
+    assert.equal(await isAppRunning(), false)
+  })
+
+  it('should rethrow errors which are neither a response nor a refused connection', async () => {
+    requestError = new Error('Cannot find module conf/production.config.js')
+    await assert.rejects(() => isAppRunning(), /Cannot find module/)
+  })
+
+  it('should rethrow other transport errors', async () => {
+    requestError = transportError('EHOSTUNREACH')
+    await assert.rejects(() => isAppRunning(), e => e.cause.code === 'EHOSTUNREACH')
+  })
+})