Merge pull request #1359 from sjg20/disk

udisks2: Be more tolerant of device-startup time

labgrid/driver/usbstoragedriver.py

@@ -45,6 +45,7 @@ class USBStorageDriver(Driver):
  )
  WAIT_FOR_MEDIUM_TIMEOUT = 10.0 # s
  WAIT_FOR_MEDIUM_SLEEP = 0.5 # s
+ MOUNT_RETRIES = 5
 
  def __attrs_post_init__(self):
  super().__attrs_post_init__()
@@ -77,15 +78,19 @@ def write_files(self, sources, target, partition, target_is_directory=True):
  Args:
  sources (List[str]): path(s) to the file(s) to be copied to the bound USB storage
  partition.
- target (str): target directory or file to copy to
+ target (PurePath): target directory or file to copy to
  partition (int): mount the specified partition or None to mount the whole disk
  target_is_directory (bool): Whether target is a directory
+
+ Raises:
+ Exception if anything goes wrong
  """
+ self._wait_for_medium(partition)
 
  self._start_wrapper()
 
  self.devpath = self._get_devpath(partition)
- mount_path = self.proxy.mount(self.devpath)
+ mount_path = self.proxy.mount(self.devpath, self.MOUNT_RETRIES)
 
  try:
  # (pathlib.PurePath(...) / "/") == "/", so we turn absolute paths into relative
@@ -222,10 +227,14 @@ def get_size(self, partition=None):
  getting the size of the root device (defaults to None)
 
  Returns:
- int: size in bytes
+ int: size in bytes, or 0 if the partition is not found
  """
  args = ["cat", f"/sys/class/block/{self._get_devpath(partition)[5:]}/size"]
- size = subprocess.check_output(self.storage.command_prefix + args)
+ try:
+ size = subprocess.check_output(self.storage.command_prefix + args)
+ except subprocess.CalledProcessError:
+ # while the medium is getting ready, the file does not yet exist
+ return 0
  try:
  return int(size) * 512
  except ValueError:

labgrid/util/agents/udisks2.py

@@ -15,25 +15,32 @@ class UDisks2Device:
  def __init__(self, devpath):
  self._logger = logging.getLogger("Device: ")
  self.devpath = devpath
- client = UDisks.Client.new_sync(None)
+ self.fs = None
+
+ def _setup(self):
+ """Try to find the devpath
 
+ Raises:
+ ValueError: no udisks2 device or no filesystem found on devpath
+ """
+ client = UDisks.Client.new_sync(None)
  manager = client.get_object_manager()
  for obj in manager.get_objects():
  block = obj.get_block()
  if not block:
  continue
 
  device_path = block.get_cached_property("Device").get_bytestring().decode('utf-8')
- if device_path == devpath:
+ if device_path == self.devpath:
  self.fs = obj.get_filesystem()
  if self.fs is None:
- raise ValueError(f"no filesystem found on {devpath}")
+ raise ValueError(f"no filesystem found on {self.devpath}")
 
  return
 
- raise ValueError(f"No udisks2 device found for {devpath}")
+ raise ValueError(f"No udisks2 device found for {self.devpath}")
 
- def mount(self, readonly=False):
+ def mount(self, readonly=False, retries=0):
  opts = GLib.Variant('a{sv}', {'options': GLib.Variant('s', 'ro' if readonly else 'rw')})
 
  try:
@@ -83,17 +90,39 @@ def unmount(self, lazy=False):
 
 _devs = {}
 
-def _get_udisks2_dev(devpath):
+def _get_udisks2_dev(devpath, retries):
+ """Try to get the udisks2 device
+
+ Args:
+ devpath (str): Device name
+ retries (int): Number of retries to allow
+
+ Raises:
+ ValueError: Failed to obtain the device (e.g. does not exist)
+ """
  if devpath not in _devs:
- _devs[devpath] = UDisks2Device(devpath=devpath)
+ dev = UDisks2Device(devpath=devpath)
+ while True:
+ try:
+ dev._setup()
+ break
+ except ValueError as exc:
+ if 'No udisks2 device' not in str(exc) or not retries:
+ raise
+ retries -= 1
+ dev._logger.warning('udisks2: Retrying %s...', devpath)
+ time.sleep(1)
+
+ # Success, so record the new device
+ _devs[devpath] = dev
  return _devs[devpath]
 
-def handle_mount(devpath):
- dev = _get_udisks2_dev(devpath)
+def handle_mount(devpath, retries=0):
+ dev = _get_udisks2_dev(devpath, retries)
  return dev.mount()
 
 def handle_unmount(devpath, lazy=False):
- dev = _get_udisks2_dev(devpath)
+ dev = _get_udisks2_dev(devpath, 0)
  return dev.unmount(lazy=lazy)
 
 methods = {