Building .NET 5.0 project Azure DevOps pipeline

Question

I'm trying to build a project in .NET 5.0 using Azure DevOps pipeline Build and I'm received this error

2020-11-14T01:59:45.8238544Z [command]"C:\Program Files\dotnet\dotnet.exe" build D:\a\1\s\XXX.csproj "-dl:CentralLogger,\"D:\a\_tasks\DotNetCoreCLI_5541a522-603c-47ad-91fc-a4b1d163081b\2.178.0\dotnet-build-helpers\Microsoft.TeamFoundation.DistributedTask.MSBuild.Logger.dll\"*ForwardingLogger,\"D:\a\_tasks\DotNetCoreCLI_5541a522-603c-47ad-91fc-a4b1d163081b\2.178.0\dotnet-build-helpers\Microsoft.TeamFoundation.DistributedTask.MSBuild.Logger.dll\""
2020-11-14T01:59:46.1472016Z Microsoft (R) Build Engine version 16.7.0+7fb82e5b2 for .NET
2020-11-14T01:59:46.1473316Z Copyright (C) Microsoft Corporation. All rights reserved.
2020-11-14T01:59:46.1473902Z 
2020-11-14T01:59:46.6006398Z   Determining projects to restore...
2020-11-14T01:59:47.2059773Z   Restored D:\a\1\s\XXX.csproj (in 234 ms).
2020-11-14T01:59:47.2119638Z   1 of 2 projects are up-to-date for restore.

    2020-11-14T01:59:47.3209350Z ##[error]C:\Program Files\dotnet\sdk\3.1.403\Microsoft.Common.CurrentVersion.targets(1177,5): Error MSB3644: The reference assemblies for .NETFramework,Version=v5.0 were not found. To resolve this, install the Developer Pack (SDK/Targeting Pack) for this framework version or retarget your application. You can download .NET Framework Developer Packs at https://aka.ms/msbuild/developerpacks

2020-11-14T01:59:47.3261839Z C:\Program Files\dotnet\sdk\3.1.403\Microsoft.Common.CurrentVersion.targets(1177,5): error MSB3644: The reference assemblies for .NETFramework,Version=v5.0 were not found. To resolve this, install the Developer Pack (SDK/Targeting Pack) for this framework version or retarget your application. You can download .NET Framework Developer Packs at https://aka.ms/msbuild/developerpacks [D:\a\1\s\XXX.csproj]
2020-11-14T01:59:47.3270768Z 
2020-11-14T01:59:47.3274231Z Build FAILED.
2020-11-14T01:59:47.3275925Z 
2020-11-14T01:59:47.3277393Z C:\Program Files\dotnet\sdk\3.1.403\Microsoft.Common.CurrentVersion.targets(1177,5): error MSB3644: The reference assemblies for .NETFramework,Version=v5.0 were not found. To resolve this, install the Developer Pack (SDK/Targeting Pack) for this framework version or retarget your application. You can download .NET Framework Developer Packs at https://aka.ms/msbuild/developerpacks [D:\a\1\s\XXX.csproj]
2020-11-14T01:59:47.3279484Z     0 Warning(s)
2020-11-14T01:59:47.3279860Z     1 Error(s)
2020-11-14T01:59:47.3280170Z 
2020-11-14T01:59:47.3280537Z Time Elapsed 00:00:01.09
2020-11-14T01:59:47.3624731Z ##[error]Error: The process 'C:\Program Files\dotnet\dotnet.exe' failed with exit code 1

Does someone know if Azure DevOps pipelines have support for building .NET 5.0 code ?

Answer 1

Yes, Azure DevOps Pipelines can build net5.0 apps.

If you are building with ".Net Core" (DotNetCoreCLI in yaml) task - add "Use .NET Core" (UseDotNet in yaml) task before it, with correct version:

- task: UseDotNet@2
  inputs:
    packageType: 'sdk'
    version: '5.0.x'

- task: DotNetCoreCLI@2
  displayName: 'dotnet build'
  inputs:
    command: 'build'

Answer 2

It's supported.

Since you are using .Net 5, instead of using Nuget restore, try to use Use .net core taskand Dotnet core task with restore command.

- task: UseDotNet@2
  displayName: 'Use .NET Core sdk 5.0.100'
  inputs:
    packageType: 'sdk'
    version: '5.0.100'
    includePreviewVersions: true

- task: DotNetCoreCLI@2
  displayName: 'dotnet restore'
  inputs:
    command: restore
    projects: '**/*.csproj'

It's strongly recommended to use dotnet restore and dotnet build tasks for projects that target .net core. See this statement from Nuget task:

Also take a look at this similar question here: Azure CI pipeline for Blazor .NET 5 doesn't work