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AIP-62: Add HookLineageCollector #40335

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181 changes: 181 additions & 0 deletions airflow/lineage/hook.py
Original file line number Diff line number Diff line change
@@ -0,0 +1,181 @@
#
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied. See the License for the
# specific language governing permissions and limitations
# under the License.
from __future__ import annotations

from typing import Union

import attr

from airflow.datasets import Dataset
from airflow.hooks.base import BaseHook
from airflow.io.store import ObjectStore
from airflow.providers_manager import ProvidersManager
from airflow.utils.log.logging_mixin import LoggingMixin

# Store context what sent lineage.
LineageContext = Union[BaseHook, ObjectStore]

_hook_lineage_collector: HookLineageCollector | None = None


@attr.define
class HookLineage:
"""Holds lineage collected by HookLineageCollector."""

inputs: list[tuple[Dataset, LineageContext]] = attr.ib(factory=list)
outputs: list[tuple[Dataset, LineageContext]] = attr.ib(factory=list)


class HookLineageCollector(LoggingMixin):
"""
HookLineageCollector is a base class for collecting hook lineage information.

It is used to collect the input and output datasets of a hook execution.
"""

def __init__(self, **kwargs):
super().__init__(**kwargs)
self.inputs: list[tuple[Dataset, LineageContext]] = []
self.outputs: list[tuple[Dataset, LineageContext]] = []

def create_dataset(
self, scheme: str | None, uri: str | None, dataset_kwargs: dict | None, dataset_extra: dict | None
) -> Dataset | None:
"""
Create a Dataset instance using the provided parameters.

This method attempts to create a Dataset instance using the given parameters.
It first checks if a URI is provided and falls back to using the default dataset factory
with the given URI if no other information is available.

If a scheme is provided but no URI, it attempts to find a dataset factory that matches
the given scheme. If no such factory is found, it logs an error message and returns None.

If dataset_kwargs is provided, it is used to pass additional parameters to the Dataset
factory. The dataset_extra parameter is also passed to the factory as an ``extra`` parameter.
"""
if uri:
# Fallback to default factory using the provided URI
return Dataset(uri=uri, extra=dataset_extra)

if not scheme:
self.log.debug(
"Missing required parameter: either 'uri' or 'scheme' must be provided to create a Dataset."
)
return None

dataset_factory = ProvidersManager().dataset_factories.get(scheme)
if not dataset_factory:
self.log.debug("Unsupported scheme: %s. Please provide a valid URI to create a Dataset.", scheme)
return None

dataset_kwargs = dataset_kwargs or {}
try:
return dataset_factory(**dataset_kwargs, extra=dataset_extra)
except Exception as e:
self.log.debug("Failed to create dataset. Skipping. Error: %s", e)
return None

def add_input_dataset(
self,
context: LineageContext,
scheme: str | None = None,
uri: str | None = None,
dataset_kwargs: dict | None = None,
dataset_extra: dict | None = None,
):
"""Add the input dataset and its corresponding hook execution context to the collector."""
dataset = self.create_dataset(
scheme=scheme, uri=uri, dataset_kwargs=dataset_kwargs, dataset_extra=dataset_extra
)
if dataset:
self.inputs.append((dataset, context))

def add_output_dataset(
self,
context: LineageContext,
scheme: str | None = None,
uri: str | None = None,
dataset_kwargs: dict | None = None,
dataset_extra: dict | None = None,
):
"""Add the output dataset and its corresponding hook execution context to the collector."""
dataset = self.create_dataset(
scheme=scheme, uri=uri, dataset_kwargs=dataset_kwargs, dataset_extra=dataset_extra
)
if dataset:
self.outputs.append((dataset, context))

@property
def collected_datasets(self) -> HookLineage:
"""Get the collected hook lineage information."""
return HookLineage(self.inputs, self.outputs)

@property
def has_collected(self) -> bool:
"""Check if any datasets have been collected."""
return len(self.inputs) != 0 or len(self.outputs) != 0


class NoOpCollector(HookLineageCollector):
"""
NoOpCollector is a hook lineage collector that does nothing.

It is used when you want to disable lineage collection.
"""

def add_input_dataset(self, *_):
pass

def add_output_dataset(self, *_):
pass

@property
def collected_datasets(
self,
) -> HookLineage:
self.log.warning(
"Data lineage tracking is disabled. Register a hook lineage reader to start tracking hook lineage."
)
return HookLineage([], [])


class HookLineageReader(LoggingMixin):
"""Class used to retrieve the hook lineage information collected by HookLineageCollector."""

def __init__(self, **kwargs):
self.lineage_collector = get_hook_lineage_collector()

def retrieve_hook_lineage(self) -> HookLineage:
"""Retrieve hook lineage from HookLineageCollector."""
hook_lineage = self.lineage_collector.collected_datasets
return hook_lineage


def get_hook_lineage_collector() -> HookLineageCollector:
"""Get singleton lineage collector."""
global _hook_lineage_collector
if not _hook_lineage_collector:
from airflow import plugins_manager

plugins_manager.initialize_hook_lineage_readers_plugins()
if plugins_manager.hook_lineage_reader_classes:
_hook_lineage_collector = HookLineageCollector()
else:
_hook_lineage_collector = NoOpCollector()
return _hook_lineage_collector
27 changes: 27 additions & 0 deletions airflow/plugins_manager.py
Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@
import os
import sys
import types
from cgitb import Hook
from pathlib import Path
from typing import TYPE_CHECKING, Any, Iterable

Expand All @@ -41,6 +42,8 @@
from airflow.utils.module_loading import import_string, qualname

if TYPE_CHECKING:
from airflow.lineage.hook import HookLineageReader

try:
import importlib_metadata as metadata
except ImportError:
Expand Down Expand Up @@ -75,6 +78,7 @@
registered_operator_link_classes: dict[str, type] | None = None
registered_ti_dep_classes: dict[str, type] | None = None
timetable_classes: dict[str, type[Timetable]] | None = None
hook_lineage_reader_classes: list[type[Hook]] | None = None
priority_weight_strategy_classes: dict[str, type[PriorityWeightStrategy]] | None = None
"""
Mapping of class names to class of OperatorLinks registered by plugins.
Expand Down Expand Up @@ -176,8 +180,12 @@ class AirflowPlugin:
# A list of timetable classes that can be used for DAG scheduling.
timetables: list[type[Timetable]] = []

# A list of listeners that can be used for tracking task and DAG states.
listeners: list[ModuleType | object] = []

# A list of hook lineage reader classes that can be used for reading lineage information from a hook.
hook_lineage_readers: list[type[HookLineageReader]] = []

# A list of priority weight strategy classes that can be used for calculating tasks weight priority.
priority_weight_strategies: list[type[PriorityWeightStrategy]] = []

Expand Down Expand Up @@ -483,6 +491,25 @@ def initialize_timetables_plugins():
}


def initialize_hook_lineage_readers_plugins():
"""Collect hook lineage reader classes registered by plugins."""
global hook_lineage_reader_classes

if hook_lineage_reader_classes is not None:
return

ensure_plugins_loaded()

if plugins is None:
raise AirflowPluginException("Can't load plugins.")

log.debug("Initialize hook lineage readers plugins")

hook_lineage_reader_classes = []
for plugin in plugins:
hook_lineage_reader_classes.extend(plugin.hook_lineage_readers)


def integrate_executor_plugins() -> None:
"""Integrate executor plugins to the context."""
global plugins
Expand Down
4 changes: 4 additions & 0 deletions airflow/provider.yaml.schema.json
Original file line number Diff line number Diff line change
Expand Up @@ -212,6 +212,10 @@
"handler": {
"type": ["string", "null"],
"description": "Normalization function for specified URI schemes. Import path to a callable taking and returning a SplitResult. 'null' specifies a no-op."
},
"factory": {
"type": ["string", "null"],
"description": "Dataset factory for specified URI. Creates AIP-60 compliant Dataset."
}
}
}
Expand Down
23 changes: 19 additions & 4 deletions airflow/providers_manager.py
Original file line number Diff line number Diff line change
Expand Up @@ -91,6 +91,7 @@ def ensure_prefix(field):
if TYPE_CHECKING:
from urllib.parse import SplitResult

from airflow.datasets import Dataset
from airflow.decorators.base import TaskDecorator
from airflow.hooks.base import BaseHook
from airflow.typing_compat import Literal
Expand Down Expand Up @@ -426,6 +427,7 @@ def __init__(self):
self._hooks_dict: dict[str, HookInfo] = {}
self._fs_set: set[str] = set()
self._dataset_uri_handlers: dict[str, Callable[[SplitResult], SplitResult]] = {}
self._dataset_factories: dict[str, Callable[..., Dataset]] = {}
self._taskflow_decorators: dict[str, Callable] = LazyDictWithCache() # type: ignore[assignment]
# keeps mapping between connection_types and hook class, package they come from
self._hook_provider_dict: dict[str, HookClassProvider] = {}
Expand Down Expand Up @@ -523,11 +525,12 @@ def initialize_providers_filesystems(self):
self._discover_filesystems()

@provider_info_cache("dataset_uris")
def initialize_providers_dataset_uri_handlers(self):
def initialize_providers_dataset_uri_handlers_and_factories(self):
"""Lazy initialization of provider dataset URI handlers."""
self.initialize_providers_list()
self._discover_dataset_uri_handlers()
self._discover_dataset_uri_handlers_and_factories()

@provider_info_cache("hook_lineage_writers")
@provider_info_cache("taskflow_decorators")
def initialize_providers_taskflow_decorator(self):
"""Lazy initialization of providers hooks."""
Expand Down Expand Up @@ -878,7 +881,7 @@ def _discover_filesystems(self) -> None:
self._fs_set.add(fs_module_name)
self._fs_set = set(sorted(self._fs_set))

def _discover_dataset_uri_handlers(self) -> None:
def _discover_dataset_uri_handlers_and_factories(self) -> None:
from airflow.datasets import normalize_noop

for provider_package, provider in self._provider_dict.items():
Expand All @@ -893,6 +896,13 @@ def _discover_dataset_uri_handlers(self) -> None:
elif not (handler := _correctness_check(provider_package, handler_path, provider)):
continue
self._dataset_uri_handlers.update((scheme, handler) for scheme in schemes)
factory_path = handler_info.get("factory")
if not (
factory_path is not None
and (factory := _correctness_check(provider_package, factory_path, provider))
):
continue
self._dataset_factories.update((scheme, factory) for scheme in schemes)

def _discover_taskflow_decorators(self) -> None:
for name, info in self._provider_dict.items():
Expand Down Expand Up @@ -1289,9 +1299,14 @@ def filesystem_module_names(self) -> list[str]:
self.initialize_providers_filesystems()
return sorted(self._fs_set)

@property
def dataset_factories(self) -> dict[str, Callable[..., Dataset]]:
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self.initialize_providers_dataset_uri_handlers_and_factories()
return self._dataset_factories

@property
def dataset_uri_handlers(self) -> dict[str, Callable[[SplitResult], SplitResult]]:
self.initialize_providers_dataset_uri_handlers()
self.initialize_providers_dataset_uri_handlers_and_factories()
return self._dataset_uri_handlers

@property
Expand Down
43 changes: 43 additions & 0 deletions docs/apache-airflow/administration-and-deployment/lineage.rst
Original file line number Diff line number Diff line change
Expand Up @@ -89,6 +89,49 @@ has outlets defined (e.g. by using ``add_outlets(..)`` or has out of the box sup

.. _precedence: https://docs.python.org/3/reference/expressions.html

Hook Lineage
------------

Airflow provides a powerful feature for tracking data lineage not only between tasks but also from hooks used within those tasks.
This functionality helps you understand how data flows throughout your Airflow pipelines.

A global instance of ``HookLineageCollector`` serves as the central hub for collecting lineage information.
Hooks can send details about datasets they interact with to this collector.
The collector then uses this data to construct AIP-60 compliant Datasets, a standard format for describing datasets.

.. code-block:: python

from airflow.lineage.hook_lineage import get_hook_lineage_collector


class CustomHook(BaseHook):
def run(self):
# run actual code
collector = get_hook_lineage_collector()
collector.add_input_dataset(self, dataset_kwargs={"scheme": "file", "path": "/tmp/in"})
collector.add_output_dataset(self, dataset_kwargs={"scheme": "file", "path": "/tmp/out"})

Lineage data collected by the ``HookLineageCollector`` can be accessed using an instance of ``HookLineageReader``,
which is registered in an Airflow plugin.

.. code-block:: python

from airflow.lineage.hook_lineage import HookLineageReader
from airflow.plugins_manager import AirflowPlugin


class CustomHookLineageReader(HookLineageReader):
def get_inputs(self):
return self.lineage_collector.collected_datasets.inputs


class HookLineageCollectionPlugin(AirflowPlugin):
name = "HookLineageCollectionPlugin"
hook_lineage_readers = [CustomHookLineageReader]

If no ``HookLineageReader`` is registered within Airflow, a default ``NoOpCollector`` is used instead.
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This collector does not create AIP-60 compliant datasets or collect lineage information.


Lineage Backend
---------------
Expand Down
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