C#: Running in Alpine Linux docker container fails with System.IO.IOException: Error loading native library "/app/runtimes/linux/native/libgrpc_csharp_ext.x64.so"

[cypressious]

What version of gRPC and what language are you using?

C#, 1.12.0

What operating system (Linux, Windows, …) and version?

Docker, Alpine Linux

What runtime / compiler are you using (e.g. python version or version of gcc)

.NET Core 2.1

What did you do?

Created a ASP.NET Core 2.1 project and Dockerfile using an Alpine Linux base image.

FROM microsoft/dotnet:2.1.300-sdk-alpine AS builder
WORKDIR /

COPY . .
RUN dotnet publish WebApplication2/WebApplication2.csproj -o /dockerout/ -c Release

FROM microsoft/dotnet:2.1.0-aspnetcore-runtime-alpine
WORKDIR /app
EXPOSE 80

COPY --from=builder /dockerout .

ENTRYPOINT ["dotnet", "WebApplication2.dll"]

See https://github.com/cypressious/grpc-docker-issue for a reproducible sample.

What did you expect to see?

The application working

What did you see instead?

Unhaled Exception: System.IO.IOException: Error loading native library "/app/runtimes/linux/native/libgrpc_csharp_ext.x64.so"
   at Grpc.Core.Internal.UnmanagedLibrary..ctor(String[] libraryPathAlternatives)
   at Grpc.Core.Internal.NativeExtension.LoadUnmanagedLibrary()
   at Grpc.Core.Internal.NativeExtension.LoadNativeMethods()
   at Grpc.Core.Internal.NativeExtension..ctor()
   at Grpc.Core.Internal.NativeExtension.Get()
   at Grpc.Core.GrpcEnvironment.GrpcNativeInit()
   at Grpc.Core.GrpcEnvironment..ctor()
   at Grpc.Core.GrpcEnvironment.AddRef()
   at Grpc.Core.Channel..ctor(String target, ChannelCredentials credentials, IEnumerable`1 options)
   at WebApplication2.Startup.ConfigureServices(IServiceCollection services) in /WebApplication2/Startup.cs:line 16
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Hosting.ConventionBasedStartup.ConfigureServices(IServiceCollection services)
   at Microsoft.AspNetCore.Hosting.Internal.WebHost.EnsureApplicationServices()
   at Microsoft.AspNetCore.Hosting.Internal.WebHost.Initialize()
   at Microsoft.AspNetCore.Hosting.WebHostBuilder.Build()
   at WebApplication2.Program.Main(String[] args) in /WebApplication2/Program.cs:line 17

Anything else we should know about your project / environment?

Changing the Dockerfile to use a non-alpine image makes it work correctly

FROM microsoft/dotnet:2.1.300-sdk AS builder
WORKDIR /

COPY . .
RUN dotnet publish WebApplication2/WebApplication2.csproj -o /dockerout/ -c Release

FROM microsoft/dotnet:2.1.0-aspnetcore-runtime
WORKDIR /app
EXPOSE 80

COPY --from=builder /dockerout .

ENTRYPOINT ["dotnet", "WebApplication2.dll"]

[dmccaffery]

Just hit the same issue, same error, same stack trace...

[vadimi]

It worked for me when I installed libc6-compat:

RUN apk update && apk add libc6-compat

[dmccaffery]

Hmm. I thought I tried that. I will double check.

[cypressious]

@vadimi this seems to have done the trick. thanks

[jtattermusch]

We don't have a distrib test currently for testing our nugets on alpine linux, we should consider adding it in the future. Otherwise, there's not much we can do about this.

[jtattermusch]

Closing this issue as things seem to be working fine if the right prerequisites are installed.