Azure Functions Demo

This repo contains code to deploy an Azure Function in a declarative fashion. The following tools are used:

• ⚙️ GitHub Actions Workflow: End-to-end deployment and build of all components
• 💪 Bicep: infrastructure-as-code for Azure Resources
• ⚡ Azure Functions: source code for the function in golang

The deployed function is a simple demo function that prints out a greeting and accepts a name parameter, based on the guide here.

$ curl https://<functionapp_name>.azurewebsites.net/api/hello?name=Mats

Hello, Mats. This HTTP triggered function executed successfully.

$ curl https://<functionapp_name>.azurewebsites.net/api/hello

This HTTP triggered function executed successfully. Pass a name in the query string for a personalized response.

Requirements

• An Azure subscription with a resource group deployed
• A service principal with Contributor permissions to the resource group
  • Add credentials as repository secrets to AZURE_CREDENTIALS

# Set up az cli: https://docs.microsoft.com/en-us/cli/azure/get-started-with-azure-cli

$ az group create -l {location} -n {resource group}

$ az ad sp create-for-rbac --name "myApp" --role contributor \
                         --scopes /subscriptions/{subscription-id}/resourceGroups/{resource-group}
                         --sdk-auth

# Replace {subscription-id}, {resource-group}, and {app-name} with
# the names of your subscription, resource group, and Azure function app.

# The command should output a JSON object similar to this:

{
  "clientId": "<GUID>",
  "clientSecret": "<GUID>",
  "subscriptionId": "<GUID>",
  "tenantId": "<GUID>",
  (...)
}

# Copy this and add as a repository secret named AZURE_CREDENTIALS

Development

Azure Resources

Deployment of Azure resources for Azure Functions is based on the guide found here - converted to Bicep.

To develop with Bicep install the necessary tooling (VS Code Extension, Bicep CLI).

Remember to edit the parameter file before deploying.

Functions

To develop the function, open the function directory as a workspace in VS Code. This allows to use the Functions extensions to work on a local project.

This is based on the guide found here. Remember to install the necessary tooling.

Run function locally

Build the function:

cd function-go/src
go build -o main .

Run the function:

## Test the package and packaged function using Azure Functions Core Tools
cd function-go
func start                              # in one terminal
curl localhost:7071/api/hello?name=Mats # in another terminal

## Alternatively run the binary without using Azure Functions Core Tools (to quickly test the go package)
cd function-go
./main                                  # in one terminal
curl localhost:8080/api/hello?name=Mats # in another terminal

Note that process running the binary will also log the requests with method, url, user agent and time to handle the request:

2021/11/10 23:04:43 About to listen on :8080. Go to https://127.0.0.1:8080/
2021/11/10 23:04:47 GET /api/hello curl/7.68.0 7.7µs
2021/11/10 23:08:08 GET /api/hello?name=Mats curl/7.68.0 38µs

Follow the guide for a more descriptive guide.

Run the deployed function

curl https://<functionapp_name>.azurewebsites.net/api/hello?name=Mats