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 plays a game of Black Jack between two players when called and prints out the result.

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

# Example output
cards: [S3 CJ DA D6 D7 D10 S2 CQ S7 D5 C6 SQ DK C5 H9 H2 H5 HK S5 DQ HQ C2 CA HJ HA C9 S9 D9 D2 D8 S4 CK H10 SA H8 D3 C8 SK C10 H3 DJ S6 C4 H7 H6 C3 H4 C7 S10 S8 D4 SJ]
points: 380
Mats: [S3 CJ D7] Sum: 20
Magnus: [DA D6 D10] Sum: 27
Winner: Mats

• An Azure subscription with Contributor permissions
• Azure CLI installed
• Go 1.19 installed - note that newer versions of Go currently is incompatible with Function apps
• A service principal/managed identity with Contributor permissions to the resource group
  • Configured OIDC federated credentials
  • Secrets added to the repository for AZURE_CLIENT_ID, AZURE_TENANT_ID, AZURE_SUBSCRIPTION_ID
• Optional: Azure Functions Core Tools and VS Code with Azure Functions extension.

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

LOCATION=norwayeast
RESOURCERGOUP=az-func-demo
APPNAME=az-func-demo-sp
SUBID="$(az account show -o tsv --query id)"

$ az group create -l $LOCATION -n $RESOURCEGROUP

$ az ad sp create-for-rbac --name $APPNAME --role contributor --scopes "/subscriptions/$SUBID/resourceGroups/$RESOURCEGROUP" --sdk-auth

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

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

# Copy these values and add as a repository secrets:
#  - AZURE_CLIENT_ID
#  - AZURE_TENANT_ID
#  - AZURE_SUBSCRIPTION_ID

# Configure OIDC federated credentials - read more https://learn.microsoft.com/en-us/azure/developer/github/connect-from-azure?tabs=azure-portal%2Cwindows#use-the-azure-login-action-with-openid-connect
$ az ad app federated-credential create --id $APP_OBJECT_ID --parameters credential.json

# ("credential.json" contains the following content)
# {
#     "name": "github",
#     "issuer": "https://token.actions.githubusercontent.com",
#     "subject": "repo:matsest/azure-functions-demo-blackjack:environment:dev",
#     "description": "Deploy to Azure",
#     "audiences": [
#         "api://AzureADTokenExchange"
#     ]
# }

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).

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.

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/blackjack # 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/blackjack # in another terminal

Follow the guide for a more descriptive guide.

The infrastructure necessary to deploy the function is contained in the bicep file with parameters. Remember to edit the parameter file before deploying this.

To deploy the infrastructure from your local machine you can run

$ az group deployment create -g $RESOURCEGROUP -f ./bicep/main.bicep -p @./bicep/main.parameters.json

To deploy the function you can run

$ cd function-go
$ func azure functionapp publish $APPNAME

Deployment via GitHub Actions will give you end-to-end deployment of both the infrastructure and function.

If you want to fork this repository you also may need to alter the workflow file to match your resource group and function app names:

env:
  DEPLOYMENTNAME: "azfunc-${{ github.run_id }}"
  RESOURCEGROUPNAME: "mxe21"
  AZURE_FUNCTIONAPP_NAME: mxe21v2

curl https://<functionapp_name>.azurewebsites.net/api/blackjack