Bug: LongPathsEnabled on Windows seems to be ignored, and results in read/write failure when paths > 256 chars.

[andymanaws]

Expected Behaviour

By enabling LongPathsEnabled on Windows you can utilise assets, and render outputs, that have >256 chars.

But renders via Deadline Cloud seem to throw errors regard file lengths exceeding 256 chars.

Current Behaviour

Job attachments assets will result in an error when syncing:

"your file path is longer than what Windows allow."

Output images fail to write in job attachments:

"Found 0 files (Output directory C:\ProgramData\Amazon\OpenJD\session-0fac1829f3cf4e848c2c18f474f8987e8oe..."

Reproduction Steps

Ensure Windows is configured correctly:
https://www.autodesk.com/support/technical/article/caas/sfdcarticles/sfdcarticles/The-Windows-10-default-path-length-limitation-MAX-PATH-is-256-characters.html

Use a texture that has a lot of characters - e.g. include

bobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbobbob

Set the output location to a folder which has >256 chars.

Render from the app - it works.
Render from Deadline - it fails.

Code Snippet

N/A

[karthikbekalp]

Hmm, I believe there was a fix explicitly to notify customers when long paths are not enabled in https://github.com/aws-deadline/deadline-cloud/pull/403/files. @AlexTranAmz do you have any ideas why this could happen even if an instance is configured properly?

[karthikbekalp]

Discussed with @AlexTranAmz, looks like we need to enable the long paths in the registry as well as add UNC paths (add \?\ to the start of the path instead of C:\ or D:).

[joel-wong-aws]

I did an initial investigation of this issue. To my understanding, Cinema 4D itself does not support long paths. I have submitted a ticket to Maxon about this.

That said, our Deadline Cloud integration code exacerbates the problem in a couple ways:

1. [Submitter side] Before submitting a job, we save the job's sticky settings to a file named <c4dfile>.deadline_render_settings.json, yielding

Traceback (most recent call last):
  File "C:\Users\testuser\DeadlineCloudSubmitter\Submitters\Cinema4D\deadline\client\ui\dialogs\submit_job_to_deadline_dialog.py", line 419, in on_submit
    self.on_create_job_bundle_callback(
  File "C:\Users\testuser\DeadlineCloudSubmitter\Submitters\Cinema4D\deadline\cinema4d_submitter\cinema4d_render_submitter.py", line 417, in on_create_job_bundle_callback
    settings.save_sticky_settings(Scene.name())
  File "C:\Users\testuser\DeadlineCloudSubmitter\Submitters\Cinema4D\deadline\cinema4d_submitter\data_classes.py", line 73, in save_sticky_settings
    with open(sticky_settings_filename, "w", encoding="utf8") as fh:
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
FileNotFoundError: [Errno 2] No such file or directory: 'C:\\Users\\testuser\\Documents\\C4D_Projects\\physical_textured123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890.deadline_render_settings.json'

The sticky settings file adds 27 characters.

2. [Submitter side] The default job history directory attempts to save (and then reload) a manifest file, which has a length increase:

Traceback (most recent call last):
  File "C:\Users\testuser\DeadlineCloudSubmitter\Submitters\Cinema4D\deadline\client\ui\dialogs\submit_job_progress_dialog.py", line 386, in _upload_background_thread
    ).upload_assets(
      ^^^^^^^^^^^^^^
  File "C:\Users\testuser\DeadlineCloudSubmitter\Submitters\Cinema4D\deadline\job_attachments\upload.py", line 1286, in upload_assets
    (partial_manifest_key, asset_manifest_hash) = self.asset_uploader.upload_assets(
                                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\testuser\DeadlineCloudSubmitter\Submitters\Cinema4D\deadline\job_attachments\upload.py", line 195, in upload_assets
    self._write_local_manifest(
  File "C:\Users\testuser\DeadlineCloudSubmitter\Submitters\Cinema4D\deadline\job_attachments\upload.py", line 253, in _write_local_manifest
    self._write_local_input_manifest(manifest_write_dir, manifest_name, manifest, root_dir_name)
  File "C:\Users\testuser\DeadlineCloudSubmitter\Submitters\Cinema4D\deadline\job_attachments\upload.py", line 274, in _write_local_input_manifest
    with open(local_manifest_file, "w") as file:
         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
FileNotFoundError: [Errno 2] No such file or directory: 'C:\\Users\\testuser\\.deadline\\job_history\\testuser-test-farm\\2025-01\\2025-01-14-11-Cinema4D-physical_textured123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901\\manifests\\d2b2c3102af5a862db950a2e30255429_input'

This can add 40 or more characters to the file path, depending on the name of your monitor profile and the original file structure.

3. [Adaptor side] If we get past this issue, the render will fail because the path

C:\Users\testuser\Documents\C4D_Projects\\physical_textured123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890.c4d

is mapped to

C:\ProgramData\Amazon\OpenJD\session-d04e4000a1754907bcb75289655c2a8ff_32sm7o\assetroot-7a6a0443639bf42cdffb\physical_textured123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890.c4d

This adds up to 109 characters to the file path (for mapped drives). In my example, it added ~70 characters.

---

Given all of this, we can take the following actions:

1. Submit a ticket to Maxon to support long paths in Cinema 4D. This is the most durable solution, although it's not clear how quickly they could added this. I have submitted a support ticket to Maxon about this!
2. Shorten the session directory on workers (addresses issue 3): this is a known issue which requires changes to the openjd-adaptor-runtime and possibly the deadline-worker-agent. We are tracking this issue.
3. Improve the error messaging for long path errors (addresses issues 1 and 2).

[joel-wong-aws]

Added two fixes:

• Improved the error messages for sticky setting failures to save: fix: improve error handling for sticky settings having a long path #148
• Truncated the job history directory to avoid long path issues: Reduce job history dir length deadline-cloud#561

I'm in communication with Maxon about adding support for long paths.

[joel-wong-aws]

Here is the public Maxon forum post about long paths: https://developers.maxon.net/forum/topic/15966/cinema-4d-python-on-windows-long-path-errors/2

[joel-wong-aws]

As described in point 2, shortening the session directory on workers is one way to help alleviate the long path issue. A PR has just been merged to make the session directory configurable, after which it can be shortened. For this to be used:

1. deadline-cloud-worker-agent needs to be released
2. A configuration change needs to be made:
   a) For service-managed fleets, we have backlogged a ticket to make a configuration change in Deadline Cloud to use a shorter session directory
   b) For customer-managed fleets, customers will have to manually make the configuration change

Note that while this will reduce the path length, it still won't fully solve the issue - the assets directory will still prefix C:\<shortdir>\session-d04e4000a1754907bcb75289655c2a8ff_32sm7o\assetroot-7a6a0443639bf42cdffb