[PROTOTYPE NOT TO BE MERGED] Dataset factories prototype

dependency/requirements.txt

@@ -12,6 +12,7 @@ importlib_resources>=1.3  # The `files()` API was introduced in `importlib_resou
 jmespath>=0.9.5, <1.0
 more_itertools~=9.0
 omegaconf~=2.3
+parse
 pip-tools~=6.5
 pluggy~=1.0.0
 PyYAML>=4.2, <7.0

kedro/framework/cli/catalog.py

@@ -1,9 +1,11 @@
 """A collection of CLI commands for working with Kedro catalog."""
-from collections import defaultdict
+import copy
+from collections import defaultdict, Iterable
 
 import click
 import yaml
 from click import secho
+from parse import parse
 
 from kedro.framework.cli.utils import KedroCliError, env_option, split_string
 from kedro.framework.project import pipelines, settings
@@ -174,3 +176,56 @@ def _add_missing_datasets_to_catalog(missing_ds, catalog_path):
     catalog_path.parent.mkdir(exist_ok=True)
     with catalog_path.open(mode="w") as catalog_file:
         yaml.safe_dump(catalog_config, catalog_file, default_flow_style=False)
+
+
+@catalog.command("show")
+@env_option
+@click.pass_obj
+def show_catalog_datasets(metadata: ProjectMetadata, env):
+    session = _create_session(metadata.package_name, env=env)
+    context = session.load_context()
+    catalog_conf = context.config_loader["catalog"]
+    secho(yaml.dump(catalog_conf))
+
+
+@catalog.command("resolve")
+@env_option
+@click.pass_obj
+def resolve_catalog_datasets(metadata: ProjectMetadata, env):
+    session = _create_session(metadata.package_name, env=env)
+    context = session.load_context()
+    catalog_conf = context.config_loader["catalog"]
+
+    # Create a list of all datasets used in the project pipelines.
+    pipeline_datasets = []
+    for pipe in pipelines.keys():
+        pl_obj = pipelines.get(pipe)
+        if pl_obj:
+            pipeline_ds = pl_obj.data_sets()
+            for ds in pipeline_ds:
+                pipeline_datasets.append(ds)
+        else:
+            existing_pls = ", ".join(sorted(pipelines.keys()))
+            raise KedroCliError(
+                f"'{pipe}' pipeline not found! Existing pipelines: {existing_pls}"
+            )
+
+    # Create a copy of the catalog config to not modify the original.
+    catalog_copy = copy.deepcopy(catalog_conf)
+    # Loop over all entries in the catalog, find the ones that contain a pattern to be matched,
+    # loop over al datasets in the pipeline and match these against the patterns.
+    # Then expand the matches and add them to the catalog copy to display on the CLI.
+    for ds_name, ds_config in catalog_conf.items():
+        if "}" in ds_name:
+            for pipeline_dataset in set(pipeline_datasets):
+                result = parse(ds_name, pipeline_dataset)
+                if result:
+                    config_copy = copy.deepcopy(ds_config)
+                    # Match results to patterns in catalog entry
+                    for key, value in config_copy.items():
+                        if isinstance(value, Iterable) and "}" in value:
+                            string_value = str(value)
+                            config_copy[key] = string_value.format_map(result.named)
+                    catalog_copy[pipeline_dataset] = config_copy
+
+    secho(yaml.dump(catalog_copy))

kedro/framework/project/__init__.py

@@ -112,7 +112,6 @@ class _ProjectSettings(LazySettings):
     )
 
     def __init__(self, *args, **kwargs):
-
         kwargs.update(
             validators=[
                 self._CONF_SOURCE,
@@ -133,6 +132,7 @@ def _load_data_wrapper(func):
     """Wrap a method in _ProjectPipelines so that data is loaded on first access.
     Taking inspiration from dynaconf.utils.functional.new_method_proxy
     """
+
     # pylint: disable=protected-access
     def inner(self, *args, **kwargs):
         self._load_data()

kedro/io/data_catalog.py

@@ -8,9 +8,11 @@
 import difflib
 import logging
 import re
-from collections import defaultdict
+from collections import defaultdict, Iterable
 from typing import Any, Dict, List, Optional, Set, Type, Union
 
+from parse import parse
+
 from kedro.io.core import (
     AbstractDataSet,
     AbstractVersionedDataSet,
@@ -139,6 +141,7 @@ def __init__(
         data_sets: Dict[str, AbstractDataSet] = None,
         feed_dict: Dict[str, Any] = None,
         layers: Dict[str, Set[str]] = None,
+        dataset_patterns: Dict[str, Any] = None,
     ) -> None:
         """``DataCatalog`` stores instances of ``AbstractDataSet``
         implementations to provide ``load`` and ``save`` capabilities from
@@ -168,6 +171,9 @@ def __init__(
         self._data_sets = dict(data_sets or {})
         self.datasets = _FrozenDatasets(self._data_sets)
         self.layers = layers
+        # Keep a record of all patterns in the catalog.
+        # {dataset pattern name : dataset pattern body}
+        self.dataset_patterns = dict(dataset_patterns or {})
 
         # import the feed dict
         if feed_dict:
@@ -255,6 +261,7 @@ class to be loaded is specified with the key ``type`` and their
             >>> catalog.save("boats", df)
         """
         data_sets = {}
+        dataset_patterns = {}
         catalog = copy.deepcopy(catalog) or {}
         credentials = copy.deepcopy(credentials) or {}
         save_version = save_version or generate_timestamp()
@@ -269,35 +276,51 @@ class to be loaded is specified with the key ``type`` and their
 
         layers: Dict[str, Set[str]] = defaultdict(set)
         for ds_name, ds_config in catalog.items():
-            ds_layer = ds_config.pop("layer", None)
-            if ds_layer is not None:
-                layers[ds_layer].add(ds_name)
-
-            ds_config = _resolve_credentials(ds_config, credentials)
-            data_sets[ds_name] = AbstractDataSet.from_config(
-                ds_name, ds_config, load_versions.get(ds_name), save_version
-            )
+            # Let's assume that any name with } in it is a dataset pattern to be matched.
+            if "}" in ds_name:
+                # Add each pattern to the dataset_patterns dict.
+                dataset_patterns[ds_name] = ds_config
+            else:
+                ds_layer = ds_config.pop("layer", None)
+                if ds_layer is not None:
+                    layers[ds_layer].add(ds_name)
 
+                ds_config = _resolve_credentials(ds_config, credentials)
+                data_sets[ds_name] = AbstractDataSet.from_config(
+                    ds_name, ds_config, load_versions.get(ds_name), save_version
+                )
         dataset_layers = layers or None
-        return cls(data_sets=data_sets, layers=dataset_layers)
+        return cls(
+            data_sets=data_sets,
+            layers=dataset_layers,
+            dataset_patterns=dataset_patterns,
+        )
 
     def _get_dataset(
         self, data_set_name: str, version: Version = None, suggest: bool = True
     ) -> AbstractDataSet:
         if data_set_name not in self._data_sets:
-            error_msg = f"DataSet '{data_set_name}' not found in the catalog"
+            # When a dataset is "used" in the pipeline that's not in the recorded catalog datasets,
+            # try to match it against the patterns in the catalog. If it's a match, resolve it to
+            # a dataset instance and add it to the catalog, so it only needs to be matched once
+            # and not everytime the dataset is used in the pipeline.
+            matched_dataset = self.match_name_against_dataset_factories(data_set_name)
+            if matched_dataset:
+                self.add(data_set_name, matched_dataset)
+            else:
+                error_msg = f"DataSet '{data_set_name}' not found in the catalog"
 
-            # Flag to turn on/off fuzzy-matching which can be time consuming and
-            # slow down plugins like `kedro-viz`
-            if suggest:
-                matches = difflib.get_close_matches(
-                    data_set_name, self._data_sets.keys()
-                )
-                if matches:
-                    suggestions = ", ".join(matches)
-                    error_msg += f" - did you mean one of these instead: {suggestions}"
+                # Flag to turn on/off fuzzy-matching which can be time consuming and
+                # slow down plugins like `kedro-viz`
+                if suggest:
+                    matches = difflib.get_close_matches(
+                        data_set_name, self._data_sets.keys()
+                    )
+                    if matches:
+                        suggestions = ", ".join(matches)
+                        error_msg += f" - did you mean one of these instead: {suggestions}"
 
-            raise DataSetNotFoundError(error_msg)
+                raise DataSetNotFoundError(error_msg)
 
         data_set = self._data_sets[data_set_name]
         if version and isinstance(data_set, AbstractVersionedDataSet):
@@ -520,6 +543,34 @@ def add_feed_dict(self, feed_dict: Dict[str, Any], replace: bool = False) -> Non
 
             self.add(data_set_name, data_set, replace)
 
+    def match_name_against_dataset_factories(self, dataset_input_name: str) -> Optional[AbstractDataSet]:
+        """
+        For a given dataset name, try to match it against the dataset patterns in the catalog.
+        If it's a match, return the dataset instance.
+        """
+        dataset = None
+        # Loop through all dataset patterns and check if the given dataset name has a match.
+        for dataset_name, dataset_config in self.dataset_patterns.items():
+            result = parse(dataset_name, dataset_input_name)
+            # If there's a match resolve the rest of the pattern to create a dataset instance.
+            # A result can be None or something like:
+            # <Result () {'root_namespace': 'germany', 'dataset_name': 'companies'}>
+            if result:
+                config_copy = copy.deepcopy(dataset_config)
+                # Match results to patterns in catalog entry
+                for key, value in config_copy.items():
+                    # Find all dataset fields that need to be resolved with
+                    # the values that were matched.
+                    if isinstance(value, Iterable) and "}" in value:
+                        string_value = str(value)
+                        # result.named: {'root_namespace': 'germany', 'dataset_name': 'companies'}
+                        # format_map fills in dict values into a string with {...} placeholders
+                        # of the same key name.
+                        config_copy[key] = string_value.format_map(result.named)
+                # Create dataset from catalog config.
+                dataset = AbstractDataSet.from_config(dataset_name, config_copy)
+        return dataset
+
     def list(self, regex_search: Optional[str] = None) -> List[str]:
         """
         List of all ``DataSet`` names registered in the catalog.
@@ -565,13 +616,33 @@ def list(self, regex_search: Optional[str] = None) -> List[str]:
             ) from exc
         return [dset_name for dset_name in self._data_sets if pattern.search(dset_name)]
 
+    def remove_pattern_matches(self, dataset_list: Set[str]):
+        """Helper method that checks which dataset names match a pattern in the catalog.
+        It returns a copy of the original list minus all those matched dataset names."""
+        if self.dataset_patterns:
+            dataset_list_minus_matched = []
+            for dataset in dataset_list:
+                # If dataset matches a pattern, remove it from the list.
+                for dataset_name in self.dataset_patterns.keys():
+                    result = parse(dataset_name, dataset)
+                    if result:
+                        break
+                    else:
+                        dataset_list_minus_matched.append(dataset)
+            return set(dataset_list_minus_matched)
+        return dataset_list
+
     def shallow_copy(self) -> "DataCatalog":
         """Returns a shallow copy of the current object.
 
         Returns:
             Copy of the current object.
         """
-        return DataCatalog(data_sets=self._data_sets, layers=self.layers)
+        return DataCatalog(
+            data_sets=self._data_sets,
+            layers=self.layers,
+            dataset_patterns=self.dataset_patterns,
+        )
 
     def __eq__(self, other):
         return (self._data_sets, self.layers) == (other._data_sets, other.layers)

kedro/runner/runner.py

@@ -73,14 +73,25 @@ def run(
         hook_manager = hook_manager or _NullPluginManager()
         catalog = catalog.shallow_copy()
 
-        unsatisfied = pipeline.inputs() - set(catalog.list())
+        # Check if there are any input datasets that aren't in the catalog and
+        # don't match a pattern in the catalog.
+        unsatisfied = catalog.remove_pattern_matches(
+            pipeline.inputs() - set(catalog.list())
+        )
         if unsatisfied:
             raise ValueError(
                 f"Pipeline input(s) {unsatisfied} not found in the DataCatalog"
             )
-
-        free_outputs = pipeline.outputs() - set(catalog.list())
-        unregistered_ds = pipeline.data_sets() - set(catalog.list())
+        # Check if there's any output datasets that aren't in the catalog and don't match a pattern
+        # in the catalog.
+        free_outputs = catalog.remove_pattern_matches(
+            pipeline.outputs() - set(catalog.list())
+        )
+        # Check which datasets used in the pipeline aren't in the catalog and don't match
+        # a pattern in the catalog and create a default dataset for those datasets.
+        unregistered_ds = catalog.remove_pattern_matches(
+            pipeline.data_sets() - set(catalog.list())
+        )
         for ds_name in unregistered_ds:
             catalog.add(ds_name, self.create_default_data_set(ds_name))