The name 'Npm' does not exist in the current context during Cake build

Question

I am running a Cake build on a Jenkins build server and am getting

error CS0101: The name 'Npm' does not exist in the current context

The task looks like this

Task("NpmInstall")
    .Does(() =>
    {
        Npm.FromPath("./src/MyProject/").Install();
    });

The Cake build works perfectly on my development machine with Visual Studio 2017 installed so I know the script is good, but for some reason it throws this error on the Jenkins build server. I am guessing I have some piece of tooling installed on my development machine that doesn't exist on the Jenkins machine, but I can't seem to find what that is.

Below is the diagnostic output from the last build

Preparing to run build script...
Chocolatey v0.10.5
Nothing to change. Config already set.
Chocolatey v0.10.5
Installing the following packages:
gitversion.portable
By installing you accept licenses for the packages.
GitVersion.Portable v4.0.0-beta0011 already installed.
 Use --force to reinstall, specify a version to install, or try upgrade.

Chocolatey installed 0/1 packages. 0 packages failed.
 See the log for details (C:\ProgramData\chocolatey\logs\chocolatey.log).

Warnings:
 - gitversion.portable - GitVersion.Portable v4.0.0-beta0011 already installed.
 Use --force to reinstall, specify a version to install, or try upgrade.
Running build script...
Module directory does not exist.
Analyzing build script...
Analyzing C:/Program Files (x86)/Jenkins/workspace/release-1.0.0/build.cake...
Processing build script...
Installing addins...
Package Cake.Npm has already been installed.
The addin Cake.Npm will reference Cake.Npm.dll.
Creating script session...
Adding reference to mscorlib.dll...
Adding reference to System.Core.dll...
Adding reference to Cake.Core.dll...
Adding reference to Cake.Common.dll...
Adding reference to Cake.exe...
Adding reference to System.dll...
Adding reference to System.Xml.dll...
Adding reference to System.Xml.Linq.dll...
Adding reference to System.Data.dll...
Adding reference to Cake.Npm.dll...
Importing namespace Cake.Common...
Importing namespace Cake.Common.Build...
Importing namespace Cake.Common.Build.AppVeyor...
Importing namespace Cake.Common.Build.AppVeyor.Data...
Importing namespace Cake.Common.Build.Bamboo...
Importing namespace Cake.Common.Build.Bamboo.Data...
Importing namespace Cake.Common.Build.BitbucketPipelines...
Importing namespace Cake.Common.Build.BitbucketPipelines.Data...
Importing namespace Cake.Common.Build.Bitrise...
Importing namespace Cake.Common.Build.Bitrise.Data...
Importing namespace Cake.Common.Build.ContinuaCI...
Importing namespace Cake.Common.Build.ContinuaCI.Data...
Importing namespace Cake.Common.Build.GitLabCI...
Importing namespace Cake.Common.Build.GitLabCI.Data...
Importing namespace Cake.Common.Build.GoCD...
Importing namespace Cake.Common.Build.GoCD.Data...
Importing namespace Cake.Common.Build.Jenkins...
Importing namespace Cake.Common.Build.Jenkins.Data...
Importing namespace Cake.Common.Build.MyGet...
Importing namespace Cake.Common.Build.TeamCity...
Importing namespace Cake.Common.Build.TFBuild...
Importing namespace Cake.Common.Build.TFBuild.Data...
Importing namespace Cake.Common.Build.TravisCI...
Importing namespace Cake.Common.Build.TravisCI.Data...
Importing namespace Cake.Common.Diagnostics...
Importing namespace Cake.Common.IO...
Importing namespace Cake.Common.IO.Paths...
Importing namespace Cake.Common.Net...
Importing namespace Cake.Common.Security...
Importing namespace Cake.Common.Solution...
Importing namespace Cake.Common.Solution.Project...
Importing namespace Cake.Common.Solution.Project.Properties...
Importing namespace Cake.Common.Solution.Project.XmlDoc...
Importing namespace Cake.Common.Text...
Importing namespace Cake.Common.Tools...
Importing namespace Cake.Common.Tools.Cake...
Importing namespace Cake.Common.Tools.Chocolatey...
Importing namespace Cake.Common.Tools.Chocolatey.ApiKey...
Importing namespace Cake.Common.Tools.Chocolatey.Config...
Importing namespace Cake.Common.Tools.Chocolatey.Features...
Importing namespace Cake.Common.Tools.Chocolatey.Install...
Importing namespace Cake.Common.Tools.Chocolatey.New...
Importing namespace Cake.Common.Tools.Chocolatey.Pack...
Importing namespace Cake.Common.Tools.Chocolatey.Pin...
Importing namespace Cake.Common.Tools.Chocolatey.Push...
Importing namespace Cake.Common.Tools.Chocolatey.Sources...
Importing namespace Cake.Common.Tools.Chocolatey.Uninstall...
Importing namespace Cake.Common.Tools.Chocolatey.Upgrade...
Importing namespace Cake.Common.Tools.DotCover...
Importing namespace Cake.Common.Tools.DotCover.Analyse...
Importing namespace Cake.Common.Tools.DotCover.Cover...
Importing namespace Cake.Common.Tools.DotCover.Merge...
Importing namespace Cake.Common.Tools.DotCover.Report...
Importing namespace Cake.Common.Tools.DotNetCore...
Importing namespace Cake.Common.Tools.DotNetCore.Build...
Importing namespace Cake.Common.Tools.DotNetCore.Execute...
Importing namespace Cake.Common.Tools.DotNetCore.Pack...
Importing namespace Cake.Common.Tools.DotNetCore.Publish...
Importing namespace Cake.Common.Tools.DotNetCore.Restore...
Importing namespace Cake.Common.Tools.DotNetCore.Run...
Importing namespace Cake.Common.Tools.DotNetCore.Test...
Importing namespace Cake.Common.Tools.DupFinder...
Importing namespace Cake.Common.Tools.Fixie...
Importing namespace Cake.Common.Tools.GitLink...
Importing namespace Cake.Common.Tools.GitReleaseManager...
Importing namespace Cake.Common.Tools.GitReleaseManager.AddAssets...
Importing namespace Cake.Common.Tools.GitReleaseManager.Close...
Importing namespace Cake.Common.Tools.GitReleaseManager.Create...
Importing namespace Cake.Common.Tools.GitReleaseManager.Export...
Importing namespace Cake.Common.Tools.GitReleaseManager.Publish...
Importing namespace Cake.Common.Tools.GitReleaseNotes...
Importing namespace Cake.Common.Tools.GitVersion...
Importing namespace Cake.Common.Tools.ILMerge...
Importing namespace Cake.Common.Tools.ILRepack...
Importing namespace Cake.Common.Tools.InnoSetup...
Importing namespace Cake.Common.Tools.InspectCode...
Importing namespace Cake.Common.Tools.MSBuild...
Importing namespace Cake.Common.Tools.MSTest...
Importing namespace Cake.Common.Tools.NSIS...
Importing namespace Cake.Common.Tools.NuGet...
Importing namespace Cake.Common.Tools.NuGet.Add...
Importing namespace Cake.Common.Tools.NuGet.Init...
Importing namespace Cake.Common.Tools.NuGet.Install...
Importing namespace Cake.Common.Tools.NuGet.Pack...
Importing namespace Cake.Common.Tools.NuGet.Push...
Importing namespace Cake.Common.Tools.NuGet.Restore...
Importing namespace Cake.Common.Tools.NuGet.SetApiKey...
Importing namespace Cake.Common.Tools.NuGet.SetProxy...
Importing namespace Cake.Common.Tools.NuGet.Sources...
Importing namespace Cake.Common.Tools.NuGet.Update...
Importing namespace Cake.Common.Tools.NUnit...
Importing namespace Cake.Common.Tools.OctopusDeploy...
Importing namespace Cake.Common.Tools.OpenCover...
Importing namespace Cake.Common.Tools.ReportGenerator...
Importing namespace Cake.Common.Tools.ReportUnit...
Importing namespace Cake.Common.Tools.Roundhouse...
Importing namespace Cake.Common.Tools.SignTool...
Importing namespace Cake.Common.Tools.SpecFlow...
Importing namespace Cake.Common.Tools.SpecFlow.StepDefinitionReport...
Importing namespace Cake.Common.Tools.SpecFlow.TestExecutionReport...
Importing namespace Cake.Common.Tools.TextTransform...
Importing namespace Cake.Common.Tools.VSTest...
Importing namespace Cake.Common.Tools.VSWhere...
Importing namespace Cake.Common.Tools.VSWhere.All...
Importing namespace Cake.Common.Tools.VSWhere.Latest...
Importing namespace Cake.Common.Tools.VSWhere.Legacy...
Importing namespace Cake.Common.Tools.VSWhere.Product...
Importing namespace Cake.Common.Tools.WiX...
Importing namespace Cake.Common.Tools.WiX.Heat...
Importing namespace Cake.Common.Tools.XBuild...
Importing namespace Cake.Common.Tools.XUnit...
Importing namespace Cake.Common.Xml...
Importing namespace Cake.Core...
Importing namespace Cake.Core.Diagnostics...
Importing namespace Cake.Core.IO...
Importing namespace Cake.Core.Scripting...
Importing namespace Cake.Npm...
Importing namespace Cake.Npm.Install...
Importing namespace Cake.Npm.Pack...
Importing namespace Cake.Npm.Publish...
Importing namespace Cake.Npm.RunScript...
Importing namespace System...
Importing namespace System.Collections.Generic...
Importing namespace System.IO...
Importing namespace System.Linq...
Importing namespace System.Text...
Importing namespace System.Threading.Tasks...
Compiling build script...
Error: Roslyn.Compilers.CompilationErrorException: C:/Program Files (x86)/Jenkins/workspace/release-1.0.0/build.cake(37,3): error CS0103: The name 'Npm' does not exist in the current context
   at Roslyn.Scripting.CommonScriptEngine.CompilationError(DiagnosticBag localDiagnostics, DiagnosticBag diagnostics)
   at Roslyn.Scripting.CommonScriptEngine.Compile(String code, String path, DiagnosticBag diagnostics, Session session, Type delegateType, Type returnType, CancellationToken cancellationToken, Boolean isInteractive, Boolean isExecute,     CommonCompilation& compilation, Delegate& factory)
   at Roslyn.Scripting.CommonScriptEngine.Execute[T](String code, String path, DiagnosticBag diagnostics, Session session, Boolean isInteractive)
   at Roslyn.Scripting.Session.Execute(String code)
   at Cake.Core.Scripting.ScriptRunner.Run(IScriptHost host, FilePath scriptPath, IDictionary`2 arguments)
   at Cake.Commands.BuildCommand.Execute(CakeOptions options)
   at Cake.CakeApplication.Run(CakeOptions options)
   at Cake.Program.Main()

What am I missing on my build server?

Answer 1

This is a result of a breaking change in the Cake.Npm addin. With 0.9.0 the maintainers essentially rewrote the API to use NpmInstall, NpmPack etc aliases to replace the older Npm.Install-style aliases.

You should be able to fix this error by changing the task to something like the below:

Task("NpmInstall")
.Does(() =>
{
    NpmInstall(s => s.FromPath("./src/MyProject/"));
});

You can see the full documentation for the new API on the website