Add legacy option for `run_as` (#1384)

## Changes
This PR partially reverts the changes in
https://github.com/databricks/cli/pull/1233 and puts the old code under
an "experimental.use_legacy_run_as" configuration. This gives customers
who ran into the breaking change made in the PR a way out.


## Tests
Both manually and via unit tests.

Manually verified that run_as works for pipelines now. And if a user
wants to use the feature they need to be both a Metastore and a
workspace admin.

---------

Error when the deploying user is a workspace admin but not a metastore
admin:
```
Error: terraform apply: exit status 1

Error: cannot update permissions: User is not a metastore admin for Metastore 'deco-uc-prod-aws-us-east-1'.

  with databricks_permissions.pipeline_foo,
  on bundle.tf.json line 23, in resource.databricks_permissions.pipeline_foo:
  23:       }
```

--------

Output of bundle validate:
```
➜  bundle-playground git:(master) ✗ cli bundle validate
Warning: You are using the legacy mode of run_as. The support for this mode is experimental and might be removed in a future release of the CLI. In order to run the DLT pipelines in your DAB as the run_as user this mode changes the owners of the pipelines to the run_as identity, which requires the user deploying the bundle to be a workspace admin, and also a Metastore admin if the pipeline target is in UC.
  at experimental.use_legacy_run_as
  in databricks.yml:13:22

Name: bundle-playground
Target: default
Workspace:
  Host: https://dbc-a39a1eb1-ef95.cloud.databricks.com
  User: shreyas.goenka@databricks.com
  Path: /Users/shreyas.goenka@databricks.com/.bundle/bundle-playground/default

Found 1 warning
```

bundle/config/experimental.go

@@ -10,6 +10,19 @@ type Experimental struct {
 	// In this case the configured wheel task will be deployed as a notebook task which install defined wheel in runtime and executes it.
 	// For more details see https://github.com/databricks/cli/pull/797 and https://github.com/databricks/cli/pull/635
 	PythonWheelWrapper bool `json:"python_wheel_wrapper,omitempty"`
+
+	// Enable legacy run_as behavior. That is:
+	// - Set the run_as identity as the owner of any pipelines in the bundle.
+	// - Do not error in the presence of resources that do not support run_as.
+	//   As of April 2024 this includes pipelines and model serving endpoints.
+	//
+	// This mode of run_as requires the deploying user to be a workspace and metastore
+	// admin. Use of this flag is not recommend for new bundles, and it is only provided
+	// to unblock customers that are stuck due to breaking changes in the run_as behavior
+	// made in https://github.com/databricks/cli/pull/1233. This flag might
+	// be removed in the future once we have a proper workaround like allowing IS_OWNER
+	// as a top-level permission in the DAB.
+	UseLegacyRunAs bool `json:"use_legacy_run_as,omitempty"`
 }
 
 type Command string

bundle/config/mutator/run_as.go

@@ -3,8 +3,10 @@ package mutator
 import (
 	"context"
 	"fmt"
+	"slices"
 
 	"github.com/databricks/cli/bundle"
+	"github.com/databricks/cli/bundle/config/resources"
 	"github.com/databricks/cli/libs/diag"
 	"github.com/databricks/cli/libs/dyn"
 	"github.com/databricks/databricks-sdk-go/service/jobs"
@@ -101,19 +103,12 @@ func validateRunAs(b *bundle.Bundle) error {
 	return nil
 }
 
-func (m *setRunAs) Apply(_ context.Context, b *bundle.Bundle) diag.Diagnostics {
-	// Mutator is a no-op if run_as is not specified in the bundle
+func setRunAsForJobs(b *bundle.Bundle) {
 	runAs := b.Config.RunAs
 	if runAs == nil {
-		return nil
+		return
 	}
 
-	// Assert the run_as configuration is valid in the context of the bundle
-	if err := validateRunAs(b); err != nil {
-		return diag.FromErr(err)
-	}
-
-	// Set run_as for jobs
 	for i := range b.Config.Resources.Jobs {
 		job := b.Config.Resources.Jobs[i]
 		if job.RunAs != nil {
@@ -124,6 +119,63 @@ func (m *setRunAs) Apply(_ context.Context, b *bundle.Bundle) diag.Diagnostics {
 			UserName:             runAs.UserName,
 		}
 	}
+}
 
+// Legacy behavior of run_as for DLT pipelines. Available under the experimental.use_run_as_legacy flag.
+// Only available to unblock customers stuck due to breaking changes in https://github.com/databricks/cli/pull/1233
+func setPipelineOwnersToRunAsIdentity(b *bundle.Bundle) {
+	runAs := b.Config.RunAs
+	if runAs == nil {
+		return
+	}
+
+	me := b.Config.Workspace.CurrentUser.UserName
+	// If user deploying the bundle and the one defined in run_as are the same
+	// Do not add IS_OWNER permission. Current user is implied to be an owner in this case.
+	// Otherwise, it will fail due to this bug https://github.com/databricks/terraform-provider-databricks/issues/2407
+	if runAs.UserName == me || runAs.ServicePrincipalName == me {
+		return
+	}
+
+	for i := range b.Config.Resources.Pipelines {
+		pipeline := b.Config.Resources.Pipelines[i]
+		pipeline.Permissions = slices.DeleteFunc(pipeline.Permissions, func(p resources.Permission) bool {
+			return (runAs.ServicePrincipalName != "" && p.ServicePrincipalName == runAs.ServicePrincipalName) ||
+				(runAs.UserName != "" && p.UserName == runAs.UserName)
+		})
+		pipeline.Permissions = append(pipeline.Permissions, resources.Permission{
+			Level:                "IS_OWNER",
+			ServicePrincipalName: runAs.ServicePrincipalName,
+			UserName:             runAs.UserName,
+		})
+	}
+}
+
+func (m *setRunAs) Apply(_ context.Context, b *bundle.Bundle) diag.Diagnostics {
+	// Mutator is a no-op if run_as is not specified in the bundle
+	runAs := b.Config.RunAs
+	if runAs == nil {
+		return nil
+	}
+
+	if b.Config.Experimental != nil && b.Config.Experimental.UseLegacyRunAs {
+		setPipelineOwnersToRunAsIdentity(b)
+		setRunAsForJobs(b)
+		return diag.Diagnostics{
+			{
+				Severity: diag.Warning,
+				Summary:  "You are using the legacy mode of run_as. The support for this mode is experimental and might be removed in a future release of the CLI. In order to run the DLT pipelines in your DAB as the run_as user this mode changes the owners of the pipelines to the run_as identity, which requires the user deploying the bundle to be a workspace admin, and also a Metastore admin if the pipeline target is in UC.",
+				Path:     dyn.MustPathFromString("experimental.use_legacy_run_as"),
+				Location: b.Config.GetLocation("experimental.use_legacy_run_as"),
+			},
+		}
+	}
+
+	// Assert the run_as configuration is valid in the context of the bundle
+	if err := validateRunAs(b); err != nil {
+		return diag.FromErr(err)
+	}
+
+	setRunAsForJobs(b)
 	return nil
 }

bundle/tests/run_as/legacy/databricks.yml

@@ -0,0 +1,68 @@
+bundle:
+  name: "run_as"
+
+run_as:
+  service_principal_name: "my_service_principal"
+
+experimental:
+  use_legacy_run_as: true
+
+resources:
+  jobs:
+    job_one:
+      name: Job One
+
+      tasks:
+        - task_key: "task_one"
+          notebook_task:
+            notebook_path: "./test.py"
+
+    job_two:
+      name: Job Two
+
+      tasks:
+        - task_key: "task_two"
+          notebook_task:
+            notebook_path: "./test.py"
+
+    job_three:
+      name: Job Three
+
+      run_as:
+        service_principal_name: "my_service_principal_for_job"
+
+      tasks:
+        - task_key: "task_three"
+          notebook_task:
+            notebook_path: "./test.py"
+
+  pipelines:
+    nyc_taxi_pipeline:
+      name: "nyc taxi loader"
+
+      permissions:
+        - level: CAN_VIEW
+          service_principal_name: my_service_principal
+        - level: CAN_VIEW
+          user_name: my_user_name
+
+      libraries:
+        - notebook:
+            path: ./dlt/nyc_taxi_loader
+
+
+  models:
+    model_one:
+      name: "skynet"
+
+  registered_models:
+    model_two:
+      name: "skynet (in UC)"
+
+  experiments:
+    experiment_one:
+      name: "experiment_one"
+
+  model_serving_endpoints:
+    model_serving_one:
+      name: "skynet"

bundle/tests/run_as_test.go

@@ -13,6 +13,7 @@ import (
 	"github.com/databricks/databricks-sdk-go/service/catalog"
 	"github.com/databricks/databricks-sdk-go/service/iam"
 	"github.com/databricks/databricks-sdk-go/service/ml"
+	"github.com/databricks/databricks-sdk-go/service/serving"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -233,3 +234,53 @@ func TestRunAsErrorNeitherUserOrSpSpecifiedAtTargetOverride(t *testing.T) {
 	configPath := filepath.FromSlash("run_as/not_allowed/neither_sp_nor_user_override/override.yml")
 	assert.EqualError(t, err, fmt.Sprintf("run_as section must specify exactly one identity. Neither service_principal_name nor user_name is specified at %s:4:12", configPath))
 }
+
+func TestLegacyRunAs(t *testing.T) {
+	b := load(t, "./run_as/legacy")
+
+	ctx := context.Background()
+	bundle.ApplyFunc(ctx, b, func(ctx context.Context, b *bundle.Bundle) diag.Diagnostics {
+		b.Config.Workspace.CurrentUser = &config.User{
+			User: &iam.User{
+				UserName: "jane@doe.com",
+			},
+		}
+		return nil
+	})
+
+	diags := bundle.Apply(ctx, b, mutator.SetRunAs())
+	assert.NoError(t, diags.Error())
+
+	assert.Len(t, b.Config.Resources.Jobs, 3)
+	jobs := b.Config.Resources.Jobs
+
+	// job_one and job_two should have the same run_as identity as the bundle.
+	assert.NotNil(t, jobs["job_one"].RunAs)
+	assert.Equal(t, "my_service_principal", jobs["job_one"].RunAs.ServicePrincipalName)
+	assert.Equal(t, "", jobs["job_one"].RunAs.UserName)
+
+	assert.NotNil(t, jobs["job_two"].RunAs)
+	assert.Equal(t, "my_service_principal", jobs["job_two"].RunAs.ServicePrincipalName)
+	assert.Equal(t, "", jobs["job_two"].RunAs.UserName)
+
+	// job_three should retain it's run_as identity.
+	assert.NotNil(t, jobs["job_three"].RunAs)
+	assert.Equal(t, "my_service_principal_for_job", jobs["job_three"].RunAs.ServicePrincipalName)
+	assert.Equal(t, "", jobs["job_three"].RunAs.UserName)
+
+	// Assert owner permissions for pipelines are set.
+	pipelines := b.Config.Resources.Pipelines
+	assert.Len(t, pipelines["nyc_taxi_pipeline"].Permissions, 2)
+
+	assert.Equal(t, "CAN_VIEW", pipelines["nyc_taxi_pipeline"].Permissions[0].Level)
+	assert.Equal(t, "my_user_name", pipelines["nyc_taxi_pipeline"].Permissions[0].UserName)
+
+	assert.Equal(t, "IS_OWNER", pipelines["nyc_taxi_pipeline"].Permissions[1].Level)
+	assert.Equal(t, "my_service_principal", pipelines["nyc_taxi_pipeline"].Permissions[1].ServicePrincipalName)
+
+	// Assert other resources are not affected.
+	assert.Equal(t, ml.Model{Name: "skynet"}, *b.Config.Resources.Models["model_one"].Model)
+	assert.Equal(t, catalog.CreateRegisteredModelRequest{Name: "skynet (in UC)"}, *b.Config.Resources.RegisteredModels["model_two"].CreateRegisteredModelRequest)
+	assert.Equal(t, ml.Experiment{Name: "experiment_one"}, *b.Config.Resources.Experiments["experiment_one"].Experiment)
+	assert.Equal(t, serving.CreateServingEndpoint{Name: "skynet"}, *b.Config.Resources.ModelServingEndpoints["model_serving_one"].CreateServingEndpoint)
+}