How to configure the Powershell path environment variable on a Windows agent when using declarative pipeline

Issue

When running a Windows agent connected to a CloudBees Jenkins controller, you may want to set the Powershell path environment variable in order to execute specific commands on the agent.

Environment

CloudBees Jenkins Enterprise

Resolution

When setting the Powershell path from a declarative pipeline, one option is to call a batch file from the pipeline. Here is an example stage which calls a batch file:

stage('Run Tests') {
  steps {
    bat 'powershell -noexit "& "".\\run-tests.ps1"""'
  }
}

The Powershell path can then be set from within the Powershell script. An example of the contents of the run-tests.ps1 file are below:

$env:path = "$env:path;C:\selenium\geckodriver-v0.21.0-win64;C:\Program Files\nodejs"

npm install
node run-selenium-tests.js

In the above example, the $env:path is appended with a folder containing the selenium geckodriver as well as the path to a nodejs installation.