Introduction

It’s essential to keep a backup plan to keep the Azure Functions healthy and working as expected. Twice I experienced the issue and ended up in incidents. Because my function code requires dependent modules that get auto-load from the PowerShell Gallery

Environment

• Azure Functions with a PowerShell worker runtime.
• Function code requires dependent modules from PowerShell Gallery.

Problem

When a PowerShell Gallery

1. Fail to work
2. Working intermittently
3. Slower in performance

Solution

When a developer creates an Azure Function with a PowerShell worker runtime, the requirements.psd1 file looks like below

# This file enables modules to be automatically managed by the Functions service.
# See https://aka.ms/functionsmanageddependency for additional information.
#
@{
    # For latest supported version, go to 'https://www.powershellgallery.com/packages/Az'. 
    # To use the Az module in your function app, please uncomment the line below.
    # 'Az' = '8.*'
}

What’s new in it? Nothing, if we need a dependent module for our code to function, we mention the module name and its version in the hashtable. For example, I need to load the PSHTML module for my function to render HTML. I need to modify it as below.

# This file enables modules to be automatically managed by the Functions service.
# See https://aka.ms/functionsmanageddependency for additional information.
#
@{
    # For latest supported version, go to 'https://www.powershellgallery.com/packages/Az'. 
    # To use the Az module in your function app, please uncomment the line below.
    # 'Az' = '8.*'
    'PSHTML' = '0.8.2'
}

What happens if the PowerShell gallery is unreachable? Azure Functions fail to work! It’s as simple as that! What’s the alternative? I created a modules folder under the project root. So, the structure of my project folder looks like below

Project Folder Structure

📦iAzFunc
┣ 📂.vscode
┃ ┗ 📜extensions.json
┣ 📂modules
┃ ┗ 📂PSHTML
┃ ┃ ┗ 📂0.8.2
┣ 📜.gitignore
┣ 📜host.json
┣ 📜local.settings.json
┣ 📜profile.ps1
┗ 📜requirements.psd1

Summary

• A maximum of 10 modules are allowed to load through requirements.psd1
• If we store modules locally, there are no limits as far as I know. But, the project folder size increases.
• To save modules locally, use the below snippet.

PS C:\iAzFunc> Save-Module -Name 'PSHTML' -Path '.\modules'

Happy Azure Functions!