File not found error on Singularity installation of Fast Downward 21.12

[Clayton Ramsey]

Hi,

I'm trying to use Fast Downward, installed using Singularity according to the directions here. I was able to successfully build and run fast-downward.sif, but it appears as though it's having serious issues with file I/O. 

In particular, when I attempt to run fast-downward on any PDDL problem, I get a file-not-found error. For example, I ran the following line in the shell and received the following output:

```

$ ./fast-downward.sif grid_world.pddl blocks.pddl
INFO     Running translator.
INFO     translator stdin: None
INFO     translator time limit: None
INFO     translator memory limit: None
INFO     translator command line string: /usr/bin/python3 /workspace/downward/builds/release/bin/translate/translate.py grid_world.pddl blocks.pddl --sas-file output.sas
Parsing...
b"Error: Could not read file: grid_world.pddl\nReason: [Errno 2] No such file or directory: 'grid_world.pddl'.\n"
translate exit code: 30

Driver aborting after translate

```

Notes on what I've found:

* I've verified that both `grid_world.pddl` and `blocks.pddl` both exist in the directory where I ran fast-downward.

* I tried giving an absolute path to these PDDL files, but this did not change the resulting.

* The version of Fast Downward that I'm using is 21.12.

* I set up fast-downward using Singularity 3.10.0 and Go 1.18.3.

* I'm working on an Ubuntu 20.04 LTS operating system, running on top of WSL on Windows 10.

I looked around in the history of this mailing list, and didn't seem to find anyone with the same issue. How should I move forward from here?

Best,

Clayton

[Malte Helmert]

Hi Clayton,

a common issue with a Windows/Linux combination is case sensitivity of
file names. On Windows, BLOCKS.PDDL and blocks.pddl is the same file
name. On Linux, it is not. Is it possible that the file name is not
actually all-lower case in reality?

I haven't seriously used Windows for a long time, but in the past
checking this was further complicated by the fact that all-caps files
like BLOCKS.PDDL would be *displayed* by Explorer as blocks.pddl, and
also you couldn't rename a file to a different capitalization of the
same name easily. To do that, you had to rename it to something else
first and then to the target filename. Maybe that is no longer an issue.

If it's not that, I can also recall someone having a similar issue in
the past that was ultimately due to access rights/some security
features, which were set too restrictive and caused files to be
invisible to the planner.

If this doesn't help, can you try running it from a command prompt and
showing us a full screenshot? Perhaps also include a "dir" command
giving us the info on the PDDL files in the directory?

Best,
Malte

On 07.06.22 20:17, Clayton Ramsey wrote:
> Hi,
> I'm trying to use Fast Downward, installed using Singularity according

> to the directions here <https://www.fast-downward.org/QuickStart>. I was

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[Clayton Ramsey]

Thanks for the help. I tried running `dir` as you recommended, and the result was that `grid_world.pddl` and `blocks.pddl` are both all lowercase.

I tried building Fast Downward from source (instead of using the Singularity image) and for some reason there was no issue in that case - I was able to get Fast Downward working correctly in that case. I suspect that the source of my original error was an interaction between how Singularity and WSL handle files, but I haven't the time or skill to confirm or deny that suspicion.

In any event, I was able to resolve my problem, so all's well that ends well.

Best,

Clayton

[Malte Helmert]

Hi Clayton,

great that you could resolve it!

For others looking at this in the future, I googled a little bit, and it
seems that there are limitations regarding how WSL maps between the
Windows and Linux file systems. Singularity also relies on a mapping
between its host OS and the containerized application, so there are
three layers involved here, and they don't seem to be fully transparent.

When googling for WSL in general, I found some general caveats regarding
the mapping between the Windows and Linux filesystem and some more
specific things related to Singularity, like this one saying that
running Singularity under WSL is not supported because WSL does not
support all necessary system calls:

https://github.com/apptainer/singularity/issues/1791

However, this is a few years old and may no longer be current.

Here is a more recent StackOverflow question that seems to fit what
you're seeing pretty well, but there are no answers:

https://stackoverflow.com/questions/69572023/singularity-container-not-binding-correctly-on-wsl2

Best,
Malte

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