Mention adding dockerignore file as resolution to NETSDK1047

[willbush]

Summary

Note added resolution is similar to netsdk1064.

Here are repeatable steps to repro the issue:

$ dotnet new worker --name dotnetapp
$ cd dotnetapp
$ curl https://raw.githubusercontent.com/dotnet/dotnet-docker/main/samples/dotnetapp/Dockerfile.alpine-x64-slim > Dockerfile
$ docker build .

Observe the error NETSDK1047 after the above command.

Adding dockerignore file to ignore bin and obj solves the error:

$ echo "**/bin/" >> .dockerignore
$ echo "**/obj/" >> .dockerignore
$ docker build .

Full console output

$ dotnet --version
6.0.202
$ dotnet new worker --name dotnetapp
The template "Worker Service" was created successfully.

Processing post-creation actions...
Running 'dotnet restore' on /home/will/code/dotnetapp/dotnetapp.csproj...
  Determining projects to restore...
  Restored /home/will/code/dotnetapp/dotnetapp.csproj (in 230 ms).
Restore succeeded.

$ cd dotnetapp
$ curl https://raw.githubusercontent.com/dotnet/dotnet-docker/main/samples/dotnetapp/Dockerfile.alpine-x64-slim > Dockerfile
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   854  100   854    0     0  27326      0 --:--:-- --:--:-- --:--:-- 27548

$ docker build .
Sending build context to Docker daemon  80.38kB
Step 1/10 : FROM mcr.microsoft.com/dotnet/sdk:6.0-alpine AS build
 ---> 0124e89c43c7
Step 2/10 : WORKDIR /source
 ---> Using cache
 ---> 1554014dffe5
Step 3/10 : COPY *.csproj .
 ---> 01caeda5ca14
Step 4/10 : RUN dotnet restore -r linux-musl-x64 /p:PublishReadyToRun=true
 ---> Running in 926d1062053f
  Determining projects to restore...
  Restored /source/dotnetapp.csproj (in 16.04 sec).
Removing intermediate container 926d1062053f
 ---> 5531fcf3a003
Step 5/10 : COPY . .
 ---> b25de1cd476a
Step 6/10 : RUN dotnet publish -c release -o /app -r linux-musl-x64 --self-contained true --no-restore /p:PublishTrimmed=true /p:PublishReadyToRun=true /p:PublishSingleFile=true
 ---> Running in 8c271c93794d
Microsoft (R) Build Engine version 17.2.0+41abc5629 for .NET
Copyright (C) Microsoft Corporation. All rights reserved.

/usr/share/dotnet/sdk/6.0.300/Sdks/Microsoft.NET.Sdk/targets/Microsoft.PackageDependencyResolution.targets(267,5): error NETSDK1047: Assets file '/source/obj/project.assets.json' doesn't have a target for 'net6.0/linux-musl-x64'. Ensure that restore has run and that you have included 'net6.0' in the TargetFrameworks for your project. You may also need to include 'linux-musl-x64' in your project's RuntimeIdentifiers. [/source/dotnetapp.csproj]
The command '/bin/sh -c dotnet publish -c release -o /app -r linux-musl-x64 --self-contained true --no-restore /p:PublishTrimmed=true /p:PublishReadyToRun=true /p:PublishSingleFile=true' returned a non-zero code: 1

$ echo "**/bin/" >> .dockerignore

$ echo "**/obj/" >> .dockerignore

$ docker build .
Sending build context to Docker daemon  10.75kB
Step 1/10 : FROM mcr.microsoft.com/dotnet/sdk:6.0-alpine AS build
 ---> 0124e89c43c7
Step 2/10 : WORKDIR /source
 ---> Using cache
 ---> 1554014dffe5
Step 3/10 : COPY *.csproj .
 ---> Using cache
 ---> 01caeda5ca14
Step 4/10 : RUN dotnet restore -r linux-musl-x64 /p:PublishReadyToRun=true
 ---> Using cache
 ---> 5531fcf3a003
Step 5/10 : COPY . .
 ---> 60d2efbfb4d0
Step 6/10 : RUN dotnet publish -c release -o /app -r linux-musl-x64 --self-contained true --no-restore /p:PublishTrimmed=true /p:PublishReadyToRun=true /p:PublishSingleFile=true
 ---> Running in c1cb541971e2
Microsoft (R) Build Engine version 17.2.0+41abc5629 for .NET
Copyright (C) Microsoft Corporation. All rights reserved.

  dotnetapp -> /source/bin/release/net6.0/linux-musl-x64/dotnetapp.dll
  Optimizing assemblies for size, which may change the behavior of the app. Be sure to test after publishing. See: https://aka.ms/dotnet-illink
  dotnetapp -> /app/
Removing intermediate container c1cb541971e2
 ---> 728b78522360
Step 7/10 : FROM mcr.microsoft.com/dotnet/runtime-deps:6.0-alpine-amd64
 ---> 00348c290af7
Step 8/10 : WORKDIR /app
 ---> Using cache
 ---> e96486253dab
Step 9/10 : COPY --from=build /app .
 ---> 59bb12244572
Step 10/10 : ENTRYPOINT ["./dotnetapp"]
 ---> Running in 6aee9eeb84d5
Removing intermediate container 6aee9eeb84d5
 ---> 0a54d15e22ce
Successfully built 0a54d15e22ce

[willbush]

I'm unable to find where in code this error message originates in the dotnet cli tool. I'm guessing it's closed source? An issue or PR to update that error message should also be done.

[tdykstra]

Thanks for this contribution. I'm just suggesting a change to the link text.

[Youssef1313]

I'm unable to find where in code this error message originates in the dotnet cli tool. I'm guessing it's closed source? An issue or PR to update that error message should also be done.

It's here