feat: import configuration from directory (#15686)

* feat: command to import configuration from a directory

This allows us to keep Superset updated from a repo:

```bash
$ superset import-directory /path/to/configs/
```

For example, I created a simple dashboard with a single chart:

PLACEHOLDER

I then exported it to a file `dashboard_export_20210714T104600.zip` and
unzipped it. After deleting the dashboard, chart, dataset, and database
I imported everything back with:

```bash
$ superset import-directory ~/Downloads/dashboard_export_20210714T104600/
```

I then changed the chart title in `~/Downloads/dashboard_export_20210714T104600/charts/Cnt_per_country_1.yaml` and ran the command again. The chart was succesfully updated:

PLACEHOLDER

* Small fixes

superset/examples/__init__.py

@@ -30,5 +30,5 @@ from .paris import load_paris_iris_geojson
 from .random_time_series import load_random_time_series_data
 from .sf_population_polygons import load_sf_population_polygons
 from .tabbed_dashboard import load_tabbed_dashboard
-from .utils import load_from_configs
+from .utils import load_examples_from_configs
 from .world_bank import load_world_bank_health_n_pop

superset/examples/utils.py

@@ -14,18 +14,29 @@
 # KIND, either express or implied.  See the License for the
 # specific language governing permissions and limitations
 # under the License.
+import logging
 import re
 from pathlib import Path
 from typing import Any, Dict
 
+import yaml
 from pkg_resources import resource_isdir, resource_listdir, resource_stream
 
+from superset.commands.exceptions import CommandInvalidError
 from superset.commands.importers.v1.examples import ImportExamplesCommand
+from superset.commands.importers.v1.utils import METADATA_FILE_NAME
+
+_logger = logging.getLogger(__name__)
 
 YAML_EXTENSIONS = {".yaml", ".yml"}
 
 
-def load_from_configs(force_data: bool = False, load_test_data: bool = False) -> None:
+def load_examples_from_configs(
+    force_data: bool = False, load_test_data: bool = False
+) -> None:
+    """
+    Load all the examples inside superset/examples/configs/.
+    """
     contents = load_contents(load_test_data)
     command = ImportExamplesCommand(contents, overwrite=True, force_data=force_data)
     command.run()
@@ -55,3 +66,35 @@ def load_contents(load_test_data: bool = False) -> Dict[str, Any]:
             )
 
     return {str(path.relative_to(root)): content for path, content in contents.items()}
+
+
+def load_configs_from_directory(
+    root: Path, overwrite: bool = True, force_data: bool = False
+) -> None:
+    """
+    Load all the examples from a given directory.
+    """
+    contents: Dict[str, str] = {}
+    queue = [root]
+    while queue:
+        path_name = queue.pop()
+        if path_name.is_dir():
+            queue.extend(path_name.glob("*"))
+        elif path_name.suffix.lower() in YAML_EXTENSIONS:
+            with open(path_name) as fp:
+                contents[str(path_name.relative_to(root))] = fp.read()
+
+    # removing "type" from the metadata allows us to import any exported model
+    # from the unzipped directory directly
+    metadata = yaml.load(contents.get(METADATA_FILE_NAME, "{}"))
+    if "type" in metadata:
+        del metadata["type"]
+    contents[METADATA_FILE_NAME] = yaml.dump(metadata)
+
+    command = ImportExamplesCommand(
+        contents, overwrite=overwrite, force_data=force_data
+    )
+    try:
+        command.run()
+    except CommandInvalidError as ex:
+        _logger.error("An error occurred: %s", ex.normalized_messages())