ADDITIONAL_DEPS environment variable has stopped working with ASP.NET Core 2.1

[tobyash86]

Description

My project is injecting an external library as a dependency for the CoreCLR profiler. It uses ADDITIONAL_DEPS environment variable to achieve that. Everything works well as long as ASP.NET Core 2.0 web application is profiled, but if I use exactly the same workflow with ASP.NET Core 2.1 my library is not found by the application.

Diagnostics

This is what I have already tried:

• profiling .NET Core 2.0 application - OK
• profiling ASP.NET Core 2.0 application - OK
• profiling .NET Core 2.1 application - OK
• profiling ASP.NET Core 2.1 application using ADDITIONAL_DEPS env var - FAILURE
• profiling ASP.NET Core 2.1 application using --additional-deps switch - FAILURE

In each of these cases, I was using the same deps.json file and dependent library.

I have found out using procmon.exe that in case of ASP.NET Core 2.1 dotnet.exe behaves differently than in other cases. Dependent assembly is NOT looked up in a location provided in *.deps.json file, but only in the profiled application directory.

Output from dottest.exe is as follows:

An assembly specified in the application dependencies manifest (hooks.deps.json) was not found:
    package: 'hooks', version: '1.0.0.0'
    path: 'C:/Program Files/Profiler/bin/hooks.dll'

I have double-checked assembly exists in this location.

And this is my *.deps.json file:

{
"runtimeTarget": {
    "name": "hooks"
  },
  "targets": {
    "hooks": {
      "hooks/1.0.0.0": {
        "runtime": {
          "C:\\Program Files\\Profiler\\bin\\hooks.dll": {}
        }
      }
    }
  },
  "libraries": {
    "hooks/1.0.0.0": {
      "type": "reference",
      "serviceable": false,
      "sha512": ""
    }
  }
}

Questions

1. How can I use additional-deps with ASP.NET Core 2.1 properly?
2. Is there some other way to inject external assembly to ASP.NET Core application?
3. Is there at least a workaround for this issue?

[Eilon]

@pranavkm / @pakrym - any thoughts on this?

[pakrym]

What the full path of deps.json file?
What is ADDITIONAL_DEPS set to?

[tobyash86]

Environment variable:
set DOTNET_ADDITIONAL_DEPS=c:\Users\MyUser\Documents\MyCompany\MyProduct\Profiler\hooks.deps.json
Physical path:
C:\Users\MyUser\Documents\MyCompany\MyProduct\Profiler\hooks.deps.json

My web application is hosted from a folder:
c:\inetpub\wwwroot\HW
and the only lookup for hooks assembly (based on procmon.exe output) is:
c:\inetpub\wwwroot\HW\hooks.dll

I will try to create a minimal repro for this issue.

[tobyash86]

Update

While I was trying to prepare a repro for ASP.NET Core 2.1 it turned out that I was able to use ADDITIONAL_DEPS environment variable successfully when running my sample application from bin/Debug directory:
dotnet.exe [AppSrcDir]\bin\Debug\netcoreapp2.1\MyApp.dll
but after running Publish (IIS) from Visual Studio and running:
dotnet.exe [AppDeployDir]\MyApp.dll
ADDITIONAL_DEPS stopped working as expected.

I have analyzed it further and noticed that the two folders contain different files, so I started to copy those files between folders and it turns out that copying MyApp.runtimeconfig.dev.json to deploy directory fixes ADDITIONAL_DEPS issue. Here is the content of this file:

{
  "runtimeOptions": {
    "additionalProbingPaths": [
      "C:\\Users\\MyUser\\.dotnet\\store\\|arch|\\|tfm|",
      "C:\\Users\\MyUser\\.nuget\\packages",
      "C:\\Program Files\\dotnet\\sdk\\NuGetFallbackFolder"
    ]
  }
}

Questions

Is it a bug or is it expected?
How to inject my assembly into the deployed application then?
Why does it work properly with ASP.NET Core 2.0?
And just a curiosity - why probing paths are impacting ADDITIONAL_DEPS resolution?

[tobyash86]

Is there any chance I will get some help from ASP.NET Core team regarding this issue?

[pakrym]

Is the app you are publishing portable or standalone?

[tobyash86]

I am not sure if this is the desired information. If it is not, then please tell me how can I check it.

[pakrym]

/cc @swaroop-sridhar @vitek-karas

[swaroop-sridhar]

@tobyash86 can you please share a repro? I'll take a look. Thanks.

[tobyash86]

Another update

I was struggling to prepare a repro because the similar thing happened also while I was trying to prepare an example for ASP.NET Core 2.0. I could not use ADDITIONAL_DEPS with my ASP.NET Core 2.0 application because there was the same issue as in case of ASP.NET Core 2.1.

It turns out that target version of ASP.NET Core for a web application is not related to this error, it is the installed runtime that causes this issue.

Repro

I have prepared a very simple repro based on some example found on GitHub. The zipped example contains also debug binaries. It was built against ASP.NET Core 2.0.

Also, the second package contains my sample assembly and its *.deps.json file to be used as a value for ADDITIONAL_DEPS environment variable.

How to reproduce:

In each case, ADDITIONAL_DEPS should point to hooks.deps.json.

Case 1: Having installed runtime and hosting for ASP.NET Core 2.0 (no 2.1 components installed). The attached example will work perfectly fine with dotnet.exe running hello-world-no-startup.dll assembly directly from the build folder. Also, after publishing it to IIS Server and running it from deployment folder it will work as expected without any errors.

Case 2: After installing runtime and hosting for ASP.NET Core 2.1 example will work properly with dotnet.exe running hello-world-no-startup.dll assembly directly from the build folder. After deploying the application to IIS Server, there will be an error preventing the application from starting (you need to run hello-world-no-startup.dll from deployment folder with ADDITIONAL_DEPS set), saying that hooks.dll defined in hooks.deps.json cannot be found.

Please let me know if you will need any help from my side.

[tobyash86]

Is there any progress regarding this issue. Can I provide any additional data to help to solve it?

[swaroop-sridhar]

Hi @tobyash86, I couldn't repro the failure on asp.net core 2.1. I was able to run the test on ASP.net2.1 on build and publish directories. I also tried publishing to IIS using webdeploy. Can you please paste the exact commands you tried, and the error?
There's no reference to hooks.dll from the program. I didn't see an error even after setting the ADDITIONAL_DEPS in the environment.
Do you have the probing paths configured correctly?

[tobyash86]

Hi @swaroop-sridhar,
I will try to revalidate my repro on several different machines to eliminate an impact from my environment.
Also, I will do the checks which you have suggested and I will let you know regarding any findings.

There's no reference to hooks.dll from the program. I didn't see an error even after setting the ADDITIONAL_DEPS in the environment.

No reference to hooks.dll is expected, as my scenario requires to inject that dll into any website dynamically.

Thanks for your engagement!

[vitek-karas]

You can also try to set COREHOST_TRACE=1 environment variable alongside your ADDITIONAL_DEPS. The process should then write detailed information about probing into the stderr which I assume ASP.NET somehow captures.

[tobyash86]

Sorry for 2 weeks delay, but I was busy with other topics.

Just a quick update: I have run the scenario on other machine and it worked properly. For now, the only difference I see is that machine 1 is Windows 7 machine, and the working one is Windows 10 machine.

For some reason on the Windows 10 machine, ADDITIONAL_DEPS environment variable is resolved properly and my hooks assembly is loaded by the CLR profiler. On Windows 7 machine lookup is done only in the website folder (after copying my assembly to that folder everything works as expected).

@swaroop-sridhar wrote:

Do you have the probing paths configured correctly?

I doubt if this has anything to do with probing paths as the json file passed in ADDITIONAL_DEPS environment variable contains a full path to hooks assembly.

Tomorrow I will perform a more detailed comparison between the two machines and let you know about my findings.