New scheduled workflow to test using the azcore backend nightly (#3591)

Since we chose an opt-in approach for the time being, the new azcore
client from #3536 is not tested by regular CI workflows. This PR adds a
nightly workflow that tests it. It's a stripped-down copy of
`master.yaml`.

We can then easily add the opt-in for azidentity auth as well.

[Here's a recent
run.](https://github.com/pulumi/pulumi-azure-native/actions/runs/11052940342/job/30707287412)
The only failures are OIDC tests, which should pass on `master` because
there's an identity defined on our Service Principal for the master
branch.

.github/workflows/azcore-scheduled.yml

@@ -0,0 +1,22 @@
+name: azcore-scheduled
+
+on:
+  schedule:
+    - cron: 15 3 * * 1-6 # 3:15 am UTC, Mon-Sat
+  workflow_dispatch: {}
+
+jobs:
+  version:
+    uses: ./.github/workflows/version.yml
+    secrets: inherit
+
+  build_test:
+    uses: ./.github/workflows/build-test.yml
+    secrets: inherit
+    needs: version
+    with:
+      ref: ${{ github.ref }}
+      version: ${{ needs.version.outputs.version }}
+      short_test: false
+      retention_days: 7
+      use_autorest: false

.github/workflows/build-test.yml

@@ -22,6 +22,10 @@ on:
         type: number
         description: The number of days for which we retain assets
         default: 90
+      use_autorest:
+        type: boolean
+        description: Whether to use autorest, not azcore
+        default: true
 
 env:
   GITHUB_TOKEN: ${{ secrets.PULUMI_BOT_TOKEN }}
@@ -41,6 +45,7 @@ env:
   ARM_SUBSCRIPTION_ID: 0282681f-7a9e-424b-80b2-96babd57a8a1
   ARM_TENANT_ID: 706143bc-e1d4-4593-aee2-c9dc60ab9be7
   PULUMI_API: https://api.pulumi-staging.io
+  PULUMI_USE_AUTOREST: ${{ inputs.use_autorest }}
 
 jobs:
   prerequisites:

provider/pkg/provider/provider.go

@@ -238,8 +238,10 @@ func (k *azureNativeProvider) Configure(ctx context.Context,
 
 func (k *azureNativeProvider) newAzureClient(armAuth autorest.Authorizer, tokenCred azcore.TokenCredential, userAgent string) (azure.AzureClient, error) {
 	if os.Getenv("PULUMI_USE_AUTOREST") == "false" {
+		logging.V(9).Infof("AzureClient: using azCore")
 		return azure.NewAzCoreClient(tokenCred, userAgent, k.getAzureCloud(), nil)
 	}
+	logging.V(9).Infof("AzureClient: using autorest")
 	return azure.NewAzureClient(k.environment, armAuth, userAgent), nil
 }
 

provider/pkg/provider/provider_test.go

@@ -400,6 +400,7 @@ func TestUsesCorrectAzureClient(t *testing.T) {
 	p := azureNativeProvider{}
 
 	t.Run("default", func(t *testing.T) {
+		t.Setenv("PULUMI_USE_AUTOREST", "")
 		client, err := p.newAzureClient(nil, &fake.TokenCredential{}, "pulumi")
 		require.NoError(t, err)
 		assert.Equal(t, "azureClientImpl", reflect.TypeOf(client).Elem().Name())