Timeout and retry calls to xcodebuild (#876)

The xcodebuild command occasionally times out. Subsequent runs behave as
expected.

build/config/ios/ios_sdk.py

@@ -21,6 +21,29 @@
   os.path.dirname(__file__), os.pardir, os.pardir, os.pardir, 'flutter', 'prebuilts',
 ))
 
+
+def run_command_with_retry(command, timeout=10, retries=3):
+  """
+  Runs a command using subprocess.check_output with timeout and retry logic.
+
+  Args:
+      command: A list representing the command and its arguments.
+      timeout: The maximum time (in seconds) to wait for each command execution.
+      retries: The number of times to retry the command if it times out.
+
+  Returns:
+      The output of the command as a bytes object if successful, otherwise
+      raises a CalledProcessError.
+  """
+  for attempt in range(1, retries + 1):
+    try:
+      result = subprocess.check_output(command, timeout=timeout)
+      return result.decode('utf-8').strip()
+    except subprocess.TimeoutExpired:
+      if attempt >= retries:
+        raise  # Re-raise the TimeoutExpired error after all retries
+
+
 def main(argv):
   parser = argparse.ArgumentParser()
   parser.add_argument(
@@ -76,7 +99,7 @@ def main(argv):
       sdk,
       'Path'
     ]
-    sdk_output = subprocess.check_output(command).decode('utf-8').strip()
+    sdk_output = run_command_with_retry(command, timeout=300)
     if symlink_path:
       symlink_target = os.path.join(sdks_path, os.path.basename(sdk_output))
       symlink(sdk_output, symlink_target)

build/mac/find_sdk.py

@@ -31,6 +31,28 @@ def parse_version(version_str):
   return [int(x) for x in re.findall(r'(\d+)', version_str)]
 
 
+def run_command_with_retry(command, timeout=10, retries=3):
+  """
+  Runs a command using subprocess.check_output with timeout and retry logic.
+
+  Args:
+      command: A list representing the command and its arguments.
+      timeout: The maximum time (in seconds) to wait for each command execution.
+      retries: The number of times to retry the command if it times out.
+
+  Returns:
+      The output of the command as a bytes object if successful, otherwise
+      raises a CalledProcessError.
+  """
+  for attempt in range(1, retries + 1):
+    try:
+      result = subprocess.check_output(command, timeout=timeout)
+      return result.decode('utf-8').strip()
+    except subprocess.TimeoutExpired:
+      if attempt >= retries:
+        raise  # Re-raise the TimeoutExpired error after all retries
+
+
 def main():
   parser = OptionParser()
   parser.add_option("--print_sdk_path",
@@ -72,7 +94,7 @@ def main():
   sdk_command = ['xcodebuild',
     '-showsdks',
     '-json']
-  sdk_json_output = subprocess.check_output(sdk_command)
+  sdk_json_output = run_command_with_retry(sdk_command, timeout=300)
   sdk_json = json.loads(sdk_json_output)
 
   best_sdk = None