Azure Function WEBSITE_RUN_FROM_PACKAGE

Azure Function WEBSITE_RUN_FROM_PACKAGE

Over the years there have been multiple ways to host Azure Functions. My current preference is to host on a linux app service plan. The purpose of this post is to describe configuration I’ve found to be optimal for building and deploying azure function code into such an app.

Microsoft Documentation

This page describes the benefits of running the azure function from a package file (zip)

Consumption Gotcha

If deploying to a consumption or elastic premium plan, additional app settings are required:

• WEBSITE_CONTENTAZUREFILECONNECTIONSTRING
• WEBSITE_CONTENTSHARE

Working Pipeline

The following is two-stage devops pipeline for a dedicated app service plan, the first stage:

• build the app
• published the compiled binaries to a /publish folder (default behaviour of dotnet publish)
• creates a zip of contents of publish folder and adds the zip as a pipeline archive

The second stage:

• downloads the content of the pipeline archive (default behaviour of deployment task)
• deploys to function app

trigger:
  - main

pool:
  vmImage: ubuntu-latest

stages:
- stage: BuildAndArchive
  jobs:
  - job: BuildAndArchiveJob
    steps:
    - script: find $(System.DefaultWorkingDirectory) -type f
      displayName: 'List all files in workspace'

    - task: UseDotNet@2
      displayName: 'Use .NET Core sdk'
      inputs:
        packageType: sdk
        version: 7.x
        installationPath: $(Agent.ToolsDirectory)/dotnet

    - script: dotnet publish $(System.DefaultWorkingDirectory)/TableStoragePerf/TableStoragePerf.AzFunc/TableStoragePerf.AzFunc.csproj --configuration Release
      displayName: 'Publish Solution'

    - script: find $(System.DefaultWorkingDirectory)/TableStoragePerf -type f
      displayName: 'List all files in workspace'

    - task: ArchiveFiles@2
      displayName: 'Archive published files'
      inputs:
        rootFolderOrFile: '$(System.DefaultWorkingDirectory)/TableStoragePerf/TableStoragePerf.AzFunc/bin/Release/net7.0/publish' 
        includeRootFolder: false
        archiveType: 'zip'
        archiveFile: '$(Pipeline.Workspace)/functionapp.zip'

    - task: PublishPipelineArtifact@1
      displayName: 'Publish Artifact'
      inputs:
        targetPath: '$(Pipeline.Workspace)/functionapp.zip'
        artifact: 'drop'

- stage: DeployFunctionApp
  jobs:
  - deployment: DeployToFunctionApp
    displayName: 'Deploy to Azure Function App'
    pool:
      vmImage: 'ubuntu-latest'
    environment: 'Development'
    strategy:
      runOnce:
        deploy:
          steps:
          - script: find $(Pipeline.Workspace) -type f
            displayName: 'List all files in workspace'
          - task: AzureFunctionApp@2
            inputs:
              connectedServiceNameARM: 'sandpit'
              appType: 'functionAppLinux'
              appName: 'func-perftest'
              package: '$(Pipeline.Workspace)/drop/functionapp.zip'
              runtimeStack: 'DOTNET-ISOLATED|7.0'
              appSettings: '-AzureWebJobsStorage__accountName "storsandpit02" -WEBSITE_RUN_FROM_PACKAGE "1" -FUNCTIONS_EXTENSION_VERSION "~4"'
              deploymentMethod: 'auto'