Deploying Azure functions issues

Deploying Azure Functions with .NET from Visual Studio Code and Azure CLI: A Practical Guide

In this article, I’ll walk you through the process of deploying Azure Functions with .NET using Visual Studio Code and how to complement it with Azure CLI for better control. This hybrid approach allows for more precise adjustments and helps mitigate common issues that may arise during deployment.

Issues with Direct Deployment from Visual Studio Code

In theory, deploying Azure Functions directly from Visual Studio Code using the Azure extension should be straightforward. However, I encountered a few recurring issues with this approach:

1. Incorrect default configuration: When deploying from VS Code, the function was deployed to an ad-hoc slot instead of the correct Resource Group.
2. Lack of control during deployment: The deployment process didn’t provide clear error messages. Everything seemed fine, but the issues only became apparent when visiting the function’s URL in Azure.
3. Project language issues: During the deployment, the FUNCTIONS_WORKER_RUNTIME variable in Azure was incorrectly set, which caused errors. This indicated that the language settings specified in VS Code were not being respected.

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Solution: Using Azure CLI for Deployment

After facing some issues with the VS Code deployment, I turned to Azure CLI, which provided more granular control over the deployment process and allowed me to directly resolve these issues.

Steps I Followed:

1. Download and Install Azure CLI
   To deploy via commands, you need to have Azure CLI installed. You can do this by following the installation instructions on the official Microsoft site.

2. Initial Publish from VS Code to Generate Base Structure
   I first used Visual Studio Code to generate the “skeleton” or base structure of the function. This automated the creation of the Function App and its basic configuration in Azure.

3. Adjust Resource Group in Azure
   After the initial publish, I logged into the Azure Portal to verify and adjust the necessary resources (in this case, the Resource Group), as the default deployment from VS Code created an ad-hoc slot for the function.

4. Login to Azure CLI
   Once the environment was set, I opened the command console in the project folder and executed the following command to log in to Azure:

   az login
   

5. Deployment with Azure CLI I used Azure CLI to perform the full deployment of the function with the following command:

    func azure functionapp publish <YourFunctionAppName> --build remote --force --dotnet
   

Command options:

• --build remote: Performs the build on Azure instead of locally.
• --force: Forces an overwrite of the existing configuration on Azure, which is helpful if previous configurations were incorrect.
• --dotnet: Specifies that the project is built with .NET. This parameter is crucial because VS Code does not always detect the project language correctly, and without it, the FUNCTIONS_WORKER_RUNTIME could be set incorrectly.

1. Results of CLI vs VS Code
   By using Azure CLI, I received much clearer feedback regarding errors or configurations that needed to be adjusted. For example, I received the following error:

   ⚠️ ` Your Azure Function App has ‘FUNCTIONS_WORKER_RUNTIME’ set to ‘dotnet’ while your local project is set to ‘None’.`⚠️

Conclusions

Deploying directly from Visual Studio Code can be useful for smaller projects or when simplicity is the goal. However, when more control and visibility into the deployment process is required—especially regarding runtime configurations and other Azure resources—the Azure CLI becomes an indispensable tool.

Benefits of Deploying with Azure CLI:

• Greater control and customization: You can adjust key settings like FUNCTIONS_WORKER_RUNTIME and control where the function is deployed (Resource Group, App Service Plan).
• Full error visibility: Error messages and warnings are far more detailed, allowing real-time debugging of issues.
• Flexibility in configuration: You can overwrite incorrect configurations using the --force parameter, something that VS Code doesn’t handle well in the case of conflicts.

Recommendations:

1. Use Visual Studio Code to generate the initial structure of your function, but perform the full deployment using Azure CLI for more precision.
2. Check configurations in the Azure Portal after each deployment, especially variables like FUNCTIONS_WORKER_RUNTIME.
3. Consider automating your deployments using Azure DevOps or CI/CD pipelines if you’re working on larger or more complex projects.

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References

• Azure CLI Documentation
• Deploy Azure Functions from Visual Studio Code

I hope this guide helps you better understand the Azure Functions deployment process and how to resolve common issues. Happy coding!