[Feature] Add databricks_mlflow_models data source (#3874)

## Changes
Add `databricks_mlflow_models` data source

## Tests
Add integration and acceptance test

- [x] `make test` run locally
- [x] relevant change in `docs/` folder
- [x] covered with integration tests in `internal/acceptance`
- [x] relevant acceptance tests are passing
- [x] using Go SDK

Resolves #3791

---------

Co-authored-by: Alex Ott <alexott@gmail.com>

docs/data-sources/mlflow_models.md

@@ -0,0 +1,42 @@
+---
+subcategory: "MLflow"
+---
+# databricks_mlflow_models Data Source
+
+-> **Note** This data source could be only used with workspace-level provider!
+
+Retrieves a list of [databricks_mlflow_model](../resources/mlflow_model.md) objects, that were created by Terraform or manually, so that special handling could be applied.
+
+## Example Usage
+
+```hcl
+data "databricks_mlflow_models" "this" {}
+
+output "model" {
+  value = data.databricks_mlflow_models.this
+}
+```
+
+```hcl
+data "databricks_mlflow_models" "this" {}
+
+check "model_list_not_empty" {
+  assert {
+    condition = length(data.databricks_mlflow_models.this.names) != 0
+    error_message = "Model list is empty."
+  }
+}
+
+check "model_list_contains_model" {
+  assert {
+    condition = contains(data.databricks_mlflow_models.this.names, "model_1")
+    error_message = "model_1 is missing in model list."
+  }
+}
+```
+
+## Attribute Reference
+
+This data source exports the following attributes:
+
+* `names` - List of names of [databricks_mlflow_model](./mlflow_model.md)

internal/acceptance/data_mlflow_models_test.go

@@ -0,0 +1,44 @@
+package acceptance
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/hashicorp/terraform-plugin-testing/terraform"
+)
+
+func TestAccDataMlflowModels(t *testing.T) {
+	WorkspaceLevel(t,
+		Step{
+			Template: `
+			resource "databricks_mlflow_model" "this" {
+			  name = "model-{var.RANDOM}"
+			
+			  description = "My MLflow model description"
+			
+			  tags {
+				key   = "key1"
+				value = "value1"
+			  }
+			  tags {
+				key   = "key2"
+				value = "value2"
+			  }
+			}			
+
+			data "databricks_mlflow_models" "this" {
+			  depends_on = [databricks_mlflow_model.this]
+			}`,
+			Check: func(s *terraform.State) error {
+				r, ok := s.RootModule().Resources["data.databricks_mlflow_models.this"]
+				if !ok {
+					return fmt.Errorf("data not found in state")
+				}
+				names := r.Primary.Attributes["names.#"]
+				if names == "" {
+					return fmt.Errorf("names are empty: %v", r.Primary.Attributes)
+				}
+				return nil
+			},
+		})
+}

internal/providers/sdkv2/sdkv2.go

@@ -100,6 +100,7 @@ func DatabricksProvider() *schema.Provider {
 			"databricks_metastores":                           catalog.DataSourceMetastores().ToResource(),
 			"databricks_mlflow_experiment":                    mlflow.DataSourceExperiment().ToResource(),
 			"databricks_mlflow_model":                         mlflow.DataSourceModel().ToResource(),
+			"databricks_mlflow_models":                        mlflow.DataSourceModels().ToResource(),
 			"databricks_mws_credentials":                      mws.DataSourceMwsCredentials().ToResource(),
 			"databricks_mws_workspaces":                       mws.DataSourceMwsWorkspaces().ToResource(),
 			"databricks_node_type":                            clusters.DataSourceNodeType().ToResource(),

mlflow/data_mlflow_models.go

@@ -0,0 +1,26 @@
+package mlflow
+
+import (
+	"context"
+	"github.com/databricks/databricks-sdk-go/service/ml"
+
+	"github.com/databricks/databricks-sdk-go"
+	"github.com/databricks/terraform-provider-databricks/common"
+)
+
+type modelsData struct {
+	Names []string `json:"names,omitempty" tf:"computed"`
+}
+
+func DataSourceModels() common.Resource {
+	return common.WorkspaceData(func(ctx context.Context, data *modelsData, w *databricks.WorkspaceClient) error {
+		list, err := w.ModelRegistry.ListModelsAll(ctx, ml.ListModelsRequest{})
+		if err != nil {
+			return err
+		}
+		for _, m := range list {
+			data.Names = append(data.Names, m.Name)
+		}
+		return nil
+	})
+}

mlflow/data_mlflow_models_test.go

@@ -0,0 +1,32 @@
+package mlflow
+
+import (
+	"github.com/databricks/databricks-sdk-go/experimental/mocks"
+	"github.com/stretchr/testify/mock"
+	"testing"
+
+	"github.com/databricks/databricks-sdk-go/service/ml"
+	"github.com/databricks/terraform-provider-databricks/qa"
+)
+
+func TestDataSourceModels(t *testing.T) {
+	qa.ResourceFixture{
+		MockWorkspaceClientFunc: func(w *mocks.MockWorkspaceClient) {
+			api := w.GetMockModelRegistryAPI()
+			api.EXPECT().ListModelsAll(mock.Anything, ml.ListModelsRequest{}).Return([]ml.Model{
+				{
+					Name: "model-01",
+				},
+				{
+					Name: "model-02",
+				},
+			}, nil)
+		},
+		Read:        true,
+		NonWritable: true,
+		Resource:    DataSourceModels(),
+		ID:          ".",
+	}.ApplyAndExpectData(t, map[string]interface{}{
+		"names": []interface{}{"model-01", "model-02"},
+	})
+}