Hard stop on image download duration threshold

Code Issues Proposed changes

Adds a wall timeout `image_download_max_timeout` to enforce an upper
bound on total download duration.
While the per-chunk timeout protects against stalled reads, downloads
that trickle in just under the timeout threshold (e.g., due to heavy
TCP retransmits) can hang for longer than intended.
Now, if the total allowed time is exceeded, the download is aborted with
a non-retryable `ImageDownloadTimeoutError` regardless of per-chunk
retry or connection success.
A value of 0 (the default) disables this feature.
Closes-Bug: #2115995
Change-Id: I3b56d21abae0488853bfed14072ba21116d47baf
Signed-off-by: Afonne-CID <afonnepaulc@gmail.com>

This commit is contained in:

Afonne-CID

2025年07月07日 14:29:30 +01:00

parent b51cc75ff3

commit e1a31eb97a

5 changed files with 69 additions and 0 deletions

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7
ironic_python_agent/config.py

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@@ -306,6 +306,13 @@ cli_opts = [

'ipa-image-download-connection-retry-interval', 10),

help='Interval (in seconds) between two attempts to establish '

'connection when downloading an image.'),

cfg.IntOpt('image_download_max_duration', min=0,

default=int(APARAMS.get(

'ipa-image-download-max-duration', 0)),

help='Maximum total duration (in seconds) allowed for '

'downloading an image. If the download exceeds this '

'duration, it will be aborted regardless of retry or '

'connection success.'),

cfg.StrOpt('ironic_api_version',

default=APARAMS.get('ipa-ironic-api-version', None),

help='Ironic API version in format "x.x". If not set, the API '

13
ironic_python_agent/errors.py

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@@ -156,6 +156,19 @@ class ImageDownloadError(RESTError):

super(ImageDownloadError, self).__init__(details)

class ImageDownloadTimeoutError(RESTError):

"""Raised when an image download operation exceeds its allowed time limit.

"""

status_code = 408

message = 'Image download timeout'

def __init__(self, image_id, msg):

details = 'Download of image {} failed: {}'.format(image_id, msg)

self.secondary_message = msg

super(ImageDownloadTimeoutError, self).__init__(details)

class ImageDownloadOutofSpaceError(ImageDownloadError):

"""Raised when an image download fails due to insufficient storage."""

pass

14
ironic_python_agent/extensions/standby.py

View File

@@ -641,7 +641,21 @@ class ImageDownload(object):

which is a constant in this module.

"""

self._last_chunk_time = None

start_time = self._time

for chunk in self._request.iter_content(IMAGE_CHUNK_SIZE):

max_download_duration = CONF.image_download_max_duration

if max_download_duration:

elapsed = time.time() - start_time

if elapsed > max_download_duration:

LOG.error('Total download timeout (%s seconds) exceeded',

max_download_duration)

raise errors.ImageDownloadTimeoutError(

self._image_info['id'],

'Download exceeded max allowed time (%s seconds)' %

max_download_duration)

# Per requests forum posts/discussions, iter_content should

# periodically yield to the caller for the client to do things

# like stopwatch and potentially interrupt the download.

25
ironic_python_agent/tests/unit/extensions/test_standby.py

View File

@@ -2214,6 +2214,31 @@ class TestImageDownload(base.IronicAgentTest):

sleep_mock.assert_called_with(10)

self.assertEqual(2, sleep_mock.call_count)

@mock.patch('time.time', autospec=True)

def test_download_image_exceeds_max_duration(self, time_mock,

requests_mock, hash_mock):

CONF.set_override('image_download_max_duration', 5)

image_info = _build_fake_image_info()

hash_mock.return_value.hexdigest.return_value = image_info[

'os_hash_value']

content = ['a'] * 10

# simulating time passing with each chunk downloaded

time_mock.side_effect = list(range(11))

response = requests_mock.return_value

response.status_code = 200

response.iter_content.return_value = content

image_download = standby.ImageDownload(image_info)

with self.assertRaisesRegex(errors.ImageDownloadTimeoutError,

'Download exceeded max allowed time'):

# Iterating triggers the timeout logic inside __iter__()

list(image_download)

@mock.patch('time.sleep', autospec=True)

def test_download_image_no_space_error_fatal(self, sleep_mock,

requests_mock, hash_mock):