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"""This module provides context for Kedro project."""
import abc
import logging.config
import os
import sys
from pathlib import Path
from typing import Any, Dict, Iterable, Union
from warnings import warn
import yaml
from kedro import __version__
from kedro.config import ConfigLoader, MissingConfigException
from kedro.io import DataCatalog
from kedro.pipeline import Pipeline
from kedro.runner import AbstractRunner, SequentialRunner
from kedro.utils import load_obj
class KedroContext(abc.ABC):
"""``KedroContext`` is the base class which holds the configuration and
Kedro's main functionality. Project-specific context class should extend
this abstract class and implement the all abstract methods.
Attributes:
CONF_ROOT: Name of root directory containing project configuration.
Default name is "conf".
Example:
::
>>> from kedro.context import KedroContext
>>> from kedro.pipeline import Pipeline
>>>
>>> class ProjectContext(KedroContext):
>>> @property
>>> def pipeline(self) -> Pipeline:
>>> return Pipeline([])
"""
CONF_ROOT = "conf"
def __init__(self, project_path: Union[Path, str], env: str = None):
"""Create a context object by providing the root of a Kedro project and
the environment configuration subfolders (see ``kedro.config.ConfigLoader``)
Raises:
KedroContextError: If there is a mismatch
between Kedro project version and package version.
Args:
project_path: Project path to define the context for.
env: Optional argument for configuration default environment to be used
for running the pipeline. If not specified, it defaults to "local".
"""
def _version_mismatch_error(context_version):
return (
"Your Kedro project version {} does not match Kedro package "
"version {} you are running. Make sure to update your project template. "
"See https://github.com/quantumblacklabs/kedro/blob/master/RELEASE.md for how to "
"migrate your Kedro project."
).format(context_version, __version__)
# check the match for major and minor version (skip patch version)
if self.project_version.split(".")[:2] != __version__.split(".")[:2]:
raise KedroContextError(_version_mismatch_error(self.project_version))
self._project_path = Path(project_path).expanduser().resolve()
self.env = env or "local"
self._setup_logging()
@property
@abc.abstractmethod
def project_name(self) -> str:
"""Abstract property for Kedro project name.
Returns:
Name of Kedro project.
"""
raise NotImplementedError(
"`{}` is a subclass of KedroContext and it must implement "
"the `project_name` property".format(self.__class__.__name__)
)
@property
@abc.abstractmethod
def project_version(self) -> str:
"""Abstract property for Kedro version.
Returns:
Kedro version.
"""
raise NotImplementedError(
"`{}` is a subclass of KedroContext and it must implement "
"the `project_version` property".format(self.__class__.__name__)
)
@property
@abc.abstractmethod
def pipeline(self) -> Pipeline:
"""Abstract property for Pipeline getter.
Returns:
Defined pipeline.
"""
raise NotImplementedError(
"`{}` is a subclass of KedroContext and it must implement "
"the `pipeline` property".format(self.__class__.__name__)
)
@property
def project_path(self) -> Path:
"""Read-only property containing Kedro's root project directory.
Returns:
Project directory.
"""
return self._project_path
def _create_catalog( # pylint: disable=no-self-use
self, conf_catalog: Dict[str, Any], conf_creds: Dict[str, Any]
) -> DataCatalog:
"""A hook for changing the creation of the DataCatalog instance.
Returns:
DataCatalog defined in `catalog.yml`.
"""
return DataCatalog.from_config(conf_catalog, conf_creds)
@property
def catalog(self) -> DataCatalog:
"""Read-only property referring to Kedro's ``DataCatalog`` for this context.
Returns:
DataCatalog defined in `catalog.yml`.
"""
conf_catalog = self.config_loader.get("catalog*", "catalog*/**")
conf_creds = self._get_config_credentials()
catalog = self._create_catalog(conf_catalog, conf_creds)
catalog.add_feed_dict(self._get_feed_dict())
return catalog
@property
def io(self) -> DataCatalog:
"""Read-only alias property referring to Kedro's ``DataCatalog`` for this
context.
Returns:
DataCatalog defined in `catalog.yml`.
"""
# pylint: disable=invalid-name
return self.catalog
def _create_config_loader( # pylint: disable=no-self-use
self, conf_paths: Iterable[str]
) -> ConfigLoader:
"""A hook for changing the creation of the ConfigLoader instance.
Returns:
Instance of `ConfigLoader`.
"""
return ConfigLoader(conf_paths)
@property
def config_loader(self) -> ConfigLoader:
"""Read-only property referring to Kedro's ``ConfigLoader`` for this
context.
Returns:
Instance of `ConfigLoader` created by `_create_config_loader()`.
"""
conf_paths = [
str(self.project_path / self.CONF_ROOT / "base"),
str(self.project_path / self.CONF_ROOT / self.env),
]
return self._create_config_loader(conf_paths)
def _setup_logging(self) -> None:
"""Register logging specified in logging directory."""
conf_logging = self.config_loader.get("logging*", "logging*/**")
logging.config.dictConfig(conf_logging)
def _get_feed_dict(self) -> Dict[str, Any]:
"""Get parameters and return the feed dictionary."""
try:
params = self.config_loader.get("parameters*", "parameters*/**")
except MissingConfigException as exc:
warn(
"Parameters not found in your Kedro project config.\n{}".format(
str(exc)
)
)
params = {}
feed_dict = {"parameters": params}
for param_name, param_value in params.items():
key = "params:{}".format(param_name)
feed_dict[key] = param_value
return feed_dict
def _get_config_credentials(self) -> Dict[str, Any]:
"""Getter for credentials specified in credentials directory."""
try:
conf_creds = self.config_loader.get("credentials*", "credentials*/**")
except MissingConfigException as exc:
warn(
"Credentials not found in your Kedro project config.\n{}".format(
str(exc)
)
)
conf_creds = {}
return conf_creds
def run( # pylint: disable=too-many-arguments
self,
tags: Iterable[str] = None,
runner: AbstractRunner = None,
node_names: Iterable[str] = None,
from_nodes: Iterable[str] = None,
to_nodes: Iterable[str] = None,
pipeline: Pipeline = None,
catalog: DataCatalog = None,
) -> Dict[str, Any]:
"""Runs the pipeline with a specified runner.
Args:
tags: An optional list of node tags which should be used to
filter the nodes of the ``Pipeline``. If specified, only the nodes
containing *any* of these tags will be run.
runner: An optional parameter specifying the runner that you want to run
the pipeline with.
node_names: An optional list of node names which should be used to
filter the nodes of the ``Pipeline``. If specified, only the nodes
with these names will be run.
from_nodes: An optional list of node names which should be used as a
starting point of the new ``Pipeline``.
to_nodes: An optional list of node names which should be used as an
end point of the new ``Pipeline``.
pipeline: Optional Pipeline to run, defaults to self.pipeline.
catalog: Optional DataCatalog to run with, defaults to self.catalog.
Raises:
KedroContextError: If the resulting ``Pipeline`` is empty
or incorrect tags are provided.
Returns:
Any node outputs that cannot be processed by the ``DataCatalog``.
These are returned in a dictionary, where the keys are defined
by the node outputs.
"""
# Report project name
logging.info("** Kedro project {}".format(self.project_path.name))
# Load the pipeline as the intersection of all conditions
pipeline = pipeline or self.pipeline
if tags:
pipeline = pipeline & self.pipeline.only_nodes_with_tags(*tags)
if not pipeline.nodes:
raise KedroContextError(
"Pipeline contains no nodes with tags: {}".format(str(tags))
)
if from_nodes:
pipeline = pipeline & self.pipeline.from_nodes(*from_nodes)
if to_nodes:
pipeline = pipeline & self.pipeline.to_nodes(*to_nodes)
if node_names:
pipeline = pipeline & self.pipeline.only_nodes(*node_names)
if not pipeline.nodes:
raise KedroContextError("Pipeline contains no nodes")
catalog = catalog or self.catalog
# Run the runner
runner = runner or SequentialRunner()
return runner.run(pipeline, catalog)
[docs]def load_context(project_path: Union[str, Path], **kwargs) -> KedroContext:
"""Loads the KedroContext object of a Kedro Project as defined in `src/<package-name>/run.py`.
This function will change the current working directory to the project path.
Args:
project_path: Path to the Kedro project.
kwargs: Optional custom arguments defined by users, which will be passed to
ProjectContext class in `run.py`. kwargs will need to be passed explicitly to
the constructor of ProjectContext.
Returns:
Instance of KedroContext class defined in Kedro project.
Raises:
KedroContextError: Either '.kedro.yml' was not found
or loaded context has package conflict.
"""
project_path = Path(project_path).expanduser().resolve()
if str(project_path) not in sys.path:
sys.path.append(str(project_path))
kedro_yaml = project_path / ".kedro.yml"
try:
with kedro_yaml.open("r") as kedro_yml:
context_path = yaml.safe_load(kedro_yml)["context_path"]
except Exception:
raise KedroContextError(
"Could not retrive 'context_path' from '.kedro.yml' in {}. If you have created "
"your project with Kedro version <0.15.0, make sure to update your project template. "
"See https://github.com/quantumblacklabs/kedro/blob/master/RELEASE.md "
"for how to migrate your Kedro project.".format(str(project_path))
)
context_class = load_obj(context_path)
context = context_class(project_path, **kwargs)
if os.getcwd() != str(project_path):
warn("Changing the current working directory to {}".format(str(project_path)))
os.chdir(str(project_path)) # Move to project root
return context
[docs]class KedroContextError(Exception):
"""Error occurred when loading project and running context pipeline."""