Fix flaky boot issues by adding a retry parameter

README.md

@@ -36,15 +36,17 @@ or if you really need OS version, leave it on the loose side (e.g.
 a device with Apple Developer account, because a Simulator UDID
 [can not be used there](https://developer.apple.com/forums/thread/693026).
 
-| Name                 | Sample values            | Description                                                                                                                        |
-| -------------------- | ------------------------ | ---------------------------------------------------------------------------------------------------------------------------------- |
-| `model`              | `iPhone 8`               | Model of the device you'd like to launch                                                                                           |
-| `os`                 | `iOS`, `tvOS`, `watchOS` | OS type of the device                                                                                                              |
-| `os_version`         | `>=14.0`                 | OS version specification in semver format                                                                                          |
-| `udid`               | `ABCD-EFGH`              | Specific UDID you'd like to launch                                                                                                 |
-| `erase_before_boot`  | `true`                   | Whether the data should be erased from device before boot. Starting from a clean state helps getting a stable environment for tests |
-| `wait_for_boot`      | `false`                  | Whether the action must wait for the Simulator to finish booting requested image                                                  |
-| `shutdown_after_job` | `true`                   | Whether to shutdown the launched Simulator after the workflow job has been finished                                                |
+| Name                   | Sample values            | Description                                                                                                                                                               |
+| ---------------------- | ------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `model`                | `iPhone 8`               | Model of the device you'd like to launch                                                                                                                                  |
+| `os`                   | `iOS`, `tvOS`, `watchOS` | OS type of the device                                                                                                                                                     |
+| `os_version`           | `>=14.0`                 | OS version specification in semver format                                                                                                                                 |
+| `udid`                 | `ABCD-EFGH`              | Specific UDID you'd like to launch                                                                                                                                        |
+| `erase_before_boot`    | `true`                   | Whether the data should be erased from device before boot. Starting from a clean state helps getting a stable environment for tests                                       |
+| `wait_for_boot`        | `false`                  | Whether the action must wait for the Simulator to finish booting requested image                                                                                          |
+| `boot_timeout_seconds` | `360`                    | Maximum number of seconds to wait for the Simulator to finish booting (0 disables the timeout)                                                                            |
+| `boot_retries`         | `2`                      | Number of times to retry booting when waiting for the Simulator to finish booting fails. Setting this to 2 will result in 3 attempts: one normal attempt and two retries. |
+| `shutdown_after_job`   | `true`                   | Whether to shutdown the launched Simulator after the workflow job has been finished                                                                                       |
 
 ## Outputs
 

action.yml

@@ -29,6 +29,18 @@ inputs:
       image
     required: false
     default: 'false'
+  boot_timeout_seconds:
+    description: >
+      Maximum number of seconds to wait for the Simulator to finish booting. Use
+      0 to disable the timeout.
+    required: false
+    default: '360'
+  boot_retries:
+    description: >
+      Number of times to retry booting when waiting for the Simulator to finish
+      booting fails.
+    required: false
+    default: '3'
   shutdown_after_job:
     description: >
       Whether the Simulator should be shut down after the job has finished. This

src/main.ts

@@ -85,8 +85,31 @@ async function run(): Promise<void> {
     await simctl('boot', device.udid)
 
     if (boolean(core.getInput('wait_for_boot'))) {
+      const bootTimeoutSeconds = Number(core.getInput('boot_timeout_seconds'))
+      const bootRetries = Number(core.getInput('boot_retries'))
+
+      const bootTimeoutMs =
+        bootTimeoutSeconds > 0 ? bootTimeoutSeconds * 1000 : undefined
+
       core.info(`Waiting for device to finish booting.`)
-      await simctl('bootstatus', device.udid)
+      const maxAttempts = bootRetries + 1
+      for (let attempt = 1; attempt <= maxAttempts; attempt++) {
+        try {
+          await simctl('bootstatus', device.udid, {timeoutMs: bootTimeoutMs})
+          break
+        } catch (error) {
+          const message = error instanceof Error ? error.message : String(error)
+          core.warning(
+            `Bootstatus attempt ${attempt}/${maxAttempts} failed: ${message}`
+          )
+          if (attempt === maxAttempts) {
+            throw error
+          }
+          core.warning(`Retrying simulator boot...`)
+          await simctl('shutdown', device.udid)
+          await simctl('boot', device.udid)
+        }
+      }
     }
 
     core.setOutput('udid', device.udid)

src/xcrun.ts

@@ -55,17 +55,28 @@ export async function getDevices(): Promise<DeviceInfo[]> {
   return allDevices
 }
 
-export async function simctl(action: string, udid: string): Promise<void> {
-  await xcrun(`simctl ${action} ${udid}`)
+type ExecOptions = {
+  timeoutMs?: number
 }
 
-async function xcrun(tail: string): Promise<string> {
+export async function simctl(
+  action: string,
+  udid: string,
+  options: ExecOptions = {}
+): Promise<void> {
+  await xcrun(`simctl ${action} ${udid}`, options)
+}
+
+async function xcrun(tail: string, options: ExecOptions = {}): Promise<string> {
   const command = `xcrun ${tail}`
   core.info(`$ ${command}`)
-
+  const execOptions =
+    options.timeoutMs === undefined
+      ? {encoding: 'utf8'}
+      : {timeout: options.timeoutMs, encoding: 'utf8'}
   let res: {stdout?: string; stderr?: string} | undefined
   try {
-    res = await execAsync(command)
+    res = await execAsync(command, execOptions)
     return res.stdout || ''
   } catch (e) {
     res = e as {stdout?: string; stderr?: string}