Migrate databricks_catalogs data to Go SDK (#2038)

This PR also introduces `common.WorkspaceData` to reduce code boilerplate.

Author: nfx

catalog/data_catalogs.go

@@ -3,22 +3,20 @@ package catalog
 import (
 	"context"
 
+	"github.com/databricks/databricks-sdk-go"
 	"github.com/databricks/terraform-provider-databricks/common"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
 )
 
 func DataSourceCatalogs() *schema.Resource {
-	type catalogsData struct {
+	return common.WorkspaceData(func(ctx context.Context, data *struct {
 		Ids []string `json:"ids,omitempty" tf:"computed,slice_set"`
-	}
-	return common.DataResource(catalogsData{}, func(ctx context.Context, e any, c *common.DatabricksClient) error {
-		data := e.(*catalogsData)
-		catalogsAPI := NewCatalogsAPI(ctx, c)
-		catalogs, err := catalogsAPI.list()
+	}, w *databricks.WorkspaceClient) error {
+		catalogs, err := w.Catalogs.ListAll(ctx)
 		if err != nil {
 			return err
 		}
-		for _, v := range catalogs.Catalogs {
+		for _, v := range catalogs {
 			data.Ids = append(data.Ids, v.Name)
 		}
 		return nil

catalog/data_catalogs_test.go

@@ -28,7 +28,9 @@ func TestCatalogsData(t *testing.T) {
 		Read:        true,
 		NonWritable: true,
 		ID:          "_",
-	}.ApplyNoError(t)
+	}.ApplyAndExpectData(t, map[string]any{
+		"ids": []string{"a", "b"},
+	})
 }
 
 func TestCatalogsData_Error(t *testing.T) {

catalog/resource_catalog.go

@@ -32,11 +32,6 @@ type Catalogs struct {
 	Catalogs []CatalogInfo `json:"catalogs"`
 }
 
-func (a CatalogsAPI) list() (catalogs Catalogs, err error) {
-	err = a.client.Get(a.context, "/unity-catalog/catalogs", nil, &catalogs)
-	return
-}
-
 func (a CatalogsAPI) createCatalog(ci *CatalogInfo) error {
 	return a.client.Post(a.context, "/unity-catalog/catalogs", ci, ci)
 }

common/resource.go

@@ -8,6 +8,7 @@ import (
 	"regexp"
 	"strings"
 
+	"github.com/databricks/databricks-sdk-go"
 	"github.com/databricks/databricks-sdk-go/apierr"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
@@ -182,6 +183,7 @@ func makeEmptyBlockSuppressFunc(name string) func(k, old, new string, d *schema.
 	}
 }
 
+// Deprecated: migrate to WorkspaceData
 func DataResource(sc any, read func(context.Context, any, *DatabricksClient) error) *schema.Resource {
 	// TODO: migrate to go1.18 and get schema from second function argument?..
 	s := StructToSchema(sc, func(m map[string]*schema.Schema) map[string]*schema.Schema { return m })
@@ -213,3 +215,52 @@ func DataResource(sc any, read func(context.Context, any, *DatabricksClient) err
 		},
 	}
 }
+
+// WorkspaceData is a generic way to define data resources in Terraform provider.
+//
+// Example usage:
+//
+//	type catalogsData struct {
+//		Ids []string `json:"ids,omitempty" tf:"computed,slice_set"`
+//	}
+//	return common.WorkspaceData(func(ctx context.Context, data *catalogsData, w *databricks.WorkspaceClient) error {
+//		catalogs, err := w.Catalogs.ListAll(ctx)
+//		...
+//	})
+func WorkspaceData[T any](read func(context.Context, *T, *databricks.WorkspaceClient) error) *schema.Resource {
+	var dummy T
+	s := StructToSchema(dummy, func(m map[string]*schema.Schema) map[string]*schema.Schema { return m })
+	return &schema.Resource{
+		Schema: s,
+		ReadContext: func(ctx context.Context, d *schema.ResourceData, m any) (diags diag.Diagnostics) {
+			defer func() {
+				// using recoverable() would cause more complex rewrapping of DataToStructPointer & StructToData
+				if panic := recover(); panic != nil {
+					diags = diag.Errorf("panic: %v", panic)
+				}
+			}()
+			ptr := reflect.New(reflect.ValueOf(dummy).Type())
+			DataToReflectValue(d, &schema.Resource{Schema: s}, ptr.Elem())
+			client := m.(*DatabricksClient)
+			w, err := client.WorkspaceClient()
+			if err != nil {
+				err = nicerError(ctx, err, "read data")
+				return diag.FromErr(err)
+			}
+			err = read(ctx, ptr.Interface().(*T), w)
+			if err != nil {
+				err = nicerError(ctx, err, "read data")
+				diags = diag.FromErr(err)
+			}
+			StructToData(ptr.Elem().Interface(), s, d)
+			// check if the resource schema has the `id` attribute (marked with `json:"id"` in the provided structure).
+			// and if yes, then use it as resource ID. If not, then use default value for resource ID (`_`)
+			if _, ok := s["id"]; ok {
+				d.SetId(d.Get("id").(string))
+			} else {
+				d.SetId("_")
+			}
+			return
+		},
+	}
+}