Use a persistent cache for FMU contents

[kyllingstad]

Fixes #11.

I've submitted a companion pull request for cse-core which must be merged first: open-simulation-platform/libcosim#388. Once that is accepted, I'll revert the channel change in conanfile.txt here.

[hplatou]

Nice! Should see an effect on the 90+GB cached directories on the Jenkins slaves :)

[kyllingstad]

Closing for the time being. Will pick up again later.

[kyllingstad]

Reopening now that open-simulation-platform/libcosim#388 is ready.

Lots of changes since the approval was first given.

[kyllingstad]

I just discovered that this PR had bitrotted. I've updated it now, so it's ready for a new review. It's a rather long-standing one, so it would be good to get it done. :)

[ljamt]

This PR looks good to me. I've also tested it functionally. The cached fmus end up in localAppData/cse as expected, and the ´clean-cache` subcommand clears it.

When running the dp-ship example or inspecting the OSOM.fmu, I notice that we still create a "cse_guid" folder in localAppData/Temp. I think the importer in cse-core still extracts the fmu to the localAppData/Temp folder. Is it supposed to work like this?

[kyllingstad]

When running the dp-ship example or inspecting the OSOM.fmu, I notice that we still create a "cse_guid" folder in localAppData/Temp. I think the importer in cse-core still extracts the fmu to the localAppData/Temp folder. Is it supposed to work like this?

Weird, I can't reproduce this on my computer, neither on Windows nor Linux. Are you able to run cse inspect via a debugger and see when the folder gets created?

[ljamt]

Debugged inspect with different FMUs now.
An empty cse_guid folder is created in localAppData/Temp when line inspect.cpp line 72 is executed:

const auto uriReference = to_uri(args["uri_or_path"].as<std::string>());

This folder contains the extracted fmu after line 73 has executed:
const auto uriResolver = caching_model_uri_resolver();

All folders are deleted once the cse inspect command returns.

Sorry. Debugging outdated code. Will come back with more accurate info

[ljamt]

It is inpect.cpp line 74:
const auto model = uriResolver->lookup_model(baseUri, uriReference);
A cse_guid is created and contains only the ModelDescription.xml and is destroyed when the lookup_model returns.

Could it be the peek_model_description in importer.cpp?

[kyllingstad]

Could it be the peek_model_description in importer.cpp?

Yes. That is as expected, and as long as the directory gets deleted again afterwards, it's not a bug. Thanks for checking!