lib_lightgbm.dll isn't published to Azure App Service

[gilnahmias]

Using Microsoft.ML.LightGBM (0.9.0) NuGet package to train locally. This succeeds.
Trying to right click | Publish the solution directly from Visual Studio to Azure App Service succeeds. When trying to train a LightGBM model on the deployed Azure App Service, I get:

Unable to load DLL 'lib_lightgbm' or one of its dependencies: The specified module could not be found. (Exception from HRESULT: 0x8007007E)

Examining the published files via Kudo (Azure Portal | My Service | Console | dir) shows that lib_lightgbm.dll isn't there.

Any special steps I should take to publish this DLL and its dependencies to Azure?

Maybe related to #1945
cc @eerhardt @sfilipi

[eerhardt]

Are you running on .NET Core? If you are, it will normally be in a runtimes\win-x64 folder.

What happens if you publish to a folder on your machine? Does the file get copied to the publish folder then?

[gilnahmias]

1. Yes I'm using .NET Core 2.1.
2. When I publish to a local folder I don't see there lib_lightgbm.dll.
3. There is no lib_lightgbm.dll anywhere under .\bin\Debug\netcoreapp2.1\win-x64.
4. I can find .\obj\{Release|Debug}\netcoreapp2.1\PubTmp\Out\runtimes\win-x64\native\lib_lightgbm.dll. However, trying to copy it directly to the Azure App Service and train, I get An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B)

[eerhardt]

An attempt was made to load a program with an incorrect format.

So that's a hint. Are you publishing for x64 or x86? LightGBM only supports x64.

microsoft/LightGBM#1129

[gilnahmias]

Thanks @eerhardt!
The config combo that got it training on Azure was:

To publish:

1. Configuration = Release - x64
2. Deployment Mode = Self-Contained
3. Target Runtime = win-x64

The Azure App Service itself has Platform = 32bit.

Thanks!