01-local-settings-min.json

{
  "Values": {
    "FUNCTIONS_WORKER_RUNTIME": "dotnet"
  }
}

02-github-actions-workflow-revised.yaml

    - name: Generate OpenAPI document
      shell: pwsh
      env:
        OpenApi__HostNames: 'https://<azure-functions-app>.azurewebsites.net/api'
        AZURE_FUNCTIONS_ENVIRONMENT: 'Production'
      run: |
        cd MyFunctionApp

        mkdir outputs

        # Create local.settings.json
        cp ./local.settings.sample.json ./local.settings.json

        Start-Process -NoNewWindow func @("start","--verbose","false")
        Start-Sleep -s 60

        Invoke-RestMethod -Method Get -Uri http://localhost:7071/api/swagger.json | ConvertTo-Json -Depth 100 | Out-File -FilePath outputs/swagger.json -Force

        Get-Content -Path outputs/swagger.json -Raw

        cd ..

03-openapi.json

// OpenAPI v2
{
  "swagger": "2.0",
  "host": "<azure-functions-app>.azurewebsites.net",
  "basePath": "/api",
  "schemes": [
    "https"
  ]
}

// OpenAPI v3
{
  "openapi": "3.0.1",
  "servers": [
    {
      "url": "https://<azure-functions-app>.azurewebsites.net/api"
    }
  ]
}

04-azuredeploy-apim.bicep

// azuredeploy.bicep
param servicename string

resource apim 'Microsoft.ApiManagement/service@2021-08-01' existing = {
    name: servicename
    scope: resourceGroup(apiManagement.groupName)
}

04-openapi-v3.json

05-azuredeploy-apimapi.bicep

// azuredeploy.bicep
param openapidoc string

resource apimapi 'Microsoft.ApiManagement/service/apis@2021-08-01' = {
    name: '${apim.name}/my-api'
    properties: {
        type: 'http'
        displayName: 'My API'
        description: 'This is my API.'
        path: 'myapi'
        subscriptionRequired: true
        format: 'openapi+json-link'
        value: openapidoc
    }
}

06-az-cli-deploy.ps1

$servicename = "<my_apim_service_name>"
$openapidoc = https://<my_blob_storage_name>.blob.core.windows.net/<container>/openapi.json

az deployment group create `
    -g <resource_group_name> `
    -n <deployment_name> `
    -f ./azuredeploy.bicep `
    -p servicename=$servicename `
    -p openapidoc=$openapidoc