Writing Bicep Templates

var token = toLower(uniqueString(subscription().id, environmentName, location))
name: '${abbrs.appContainerApps}web-${token}'  // ca-web-abc123

@description('Environment (dev, prod)')
param environmentName string

@description('Azure region')
@allowed(['eastus2', 'westus2'])
param location string = 'eastus2'

output containerAppName string = containerApp.name
output webEndpoint string = 'https://${containerApp.properties.configuration.ingress.fqdn}'
output identityPrincipalId string = containerApp.identity.principalId

resource managedIdentity 'Microsoft.ManagedIdentity/userAssignedIdentities@2024-11-30' = {
  name: '${abbrs.managedIdentityUserAssignedIdentities}web-${resourceToken}'
  location: location
  properties: { isolationScope: 'Regional' }
}
output managedIdentityPrincipalId string = managedIdentity.properties.principalId

resource roleAssignment 'Microsoft.Authorization/roleAssignments@2022-04-01' = {
  name: guid(resource.id, principalId, roleId)
  properties: {
    roleDefinitionId: subscriptionResourceId('Microsoft.Authorization/roleDefinitions', roleId)
    principalId: principalId
    principalType: 'ServicePrincipal'
  }
}

resource containerApp 'Microsoft.App/containerApps@2023-05-01' = {
  identity: { type: 'UserAssigned', userAssignedIdentities: { '${userAssignedIdentityId}': {} } }
  properties: {
    configuration: {
      ingress: {
        external: true
        targetPort: 8080
        allowInsecure: false
      }
    }
    template: {
      scale: { minReplicas: 0, maxReplicas: 3 }
    }
  }
}

registries: [{
  server: containerRegistry.properties.loginServer
  identity: userAssignedIdentityId  // MI with AcrPull role
}]

az bicep build --file main.bicep
az deployment group what-if --template-file main.bicep

main.bicep (subscription scope)
├─ Resource group
├─ main-infrastructure.bicep (ACR + Container Apps Env + Log Analytics + User-Assigned MI)
├─ entra-app.bicep (SPA app + conditional OBO backend app with FIC + admin consent)
├─ main-app.bicep (Container App with MI-based ACR pull)
└─ RBAC (Cognitive Services User role via postprovision CLI)

resource containerApp 'Microsoft.App/containerApps@2024-03-01' = {
  identity: {
    type: 'UserAssigned'
    userAssignedIdentities: { '${userAssignedIdentityId}': {} }
  }
  properties: {
    managedEnvironmentId: containerAppsEnvironmentId
    configuration: {
      ingress: {
        external: true
        targetPort: 8080
        allowInsecure: false
      }
      registries: [{
        server: containerRegistry.properties.loginServer
        identity: userAssignedIdentityId  // MI-based pull, no secrets
      }]
    }
    template: {
      containers: [{
        name: 'web'
        image: containerImage
        env: containerEnv  // Base env + conditional OBO env
        resources: { cpu: json('0.5'), memory: '1Gi' }
      }]
      scale: { minReplicas: 0, maxReplicas: 3 }
    }
  }
}

output fqdn string = containerApp.properties.configuration.ingress.fqdn
output identityPrincipalId string = containerApp.identity.principalId