title: How can I pull the release ID and build number into my Azure DevOps deployed PHP app
body: <p>I'm using Azure DevOps to build and release my PHP app, currently to a staging slot within an Azure WebApp instance, so that I can warm-switch it to the production slot. The process is using Azure Pipelines to build (zip) the app from the branch, this passes the build artifact to a Releases event chain which then pushes it up to the Azure instance.</p>
  
  <p>I'm trying to pull the Azure DevOps Release ID and Build Number into the instance that's deployed to the Azure WebApp slot, but try as I might I can't get it to work. </p>
  
  <p>What I've tried so far (bash scripts, environment variables) appears to be just setting environment variables on the agent that's doing the deployment, not on the actual Azure WebApp instance.</p>
  
  <p>I've checked as much Azure DevOps and WebApp documentation as I can find, and whilst there's a few items for doing it in a Windows environment, there's not an awful lot for the Linux environment (which is what the Web App is using).</p>
  
  <p>(Documentation I've already read: <a href="https://docs.microsoft.com/en-us/azure/devops/pipelines/release/variables?view=azure-devops&amp;tabs=batch" rel="nofollow noreferrer">https://docs.microsoft.com/en-us/azure/devops/pipelines/release/variables?view=azure-devops&amp;tabs=batch</a>)</p>