Significant Changes

Following Listener API methods are considered stable and can be used for production system (were experimental feature in older Airflow versions) (#36376):

Lifecycle events:

• on_starting
• before_stopping

DagRun State Change Events:

• on_dag_run_running
• on_dag_run_success
• on_dag_run_failed

TaskInstance State Change Events:

• on_task_instance_running
• on_task_instance_success
• on_task_instance_failed

Support for Microsoft SQL-Server for Airflow Meta Database has been removed (#36514)

After discussion <https://lists.apache.org/thread/r06j306hldg03g2my1pd4nyjxg78b3h4>__ and a voting process <https://lists.apache.org/thread/pgcgmhf6560k8jbsmz8nlyoxosvltph2>__, the Airflow's PMC and Committers have reached a resolution to no longer maintain MsSQL as a supported Database Backend.

As of Airflow 2.9.0 support of MsSQL has been removed for Airflow Database Backend.

A migration script which can help migrating the database before upgrading to Airflow 2.9.0 is available in airflow-mssql-migration repo on Github <https://github.com/apache/airflow-mssql-migration>_. Note that the migration script is provided without support and warranty.

This does not affect the existing provider packages (operators and hooks), DAGs can still access and process data from MsSQL.

Dataset URIs are now validated on input (#37005)

Datasets must use a URI that conform to rules laid down in AIP-60, and the value will be automatically normalized when the DAG file is parsed. See documentation on Datasets <https://airflow.apache.org/docs/apache-airflow/stable/authoring-and-scheduling/datasets.html>_ for a more detailed description on the rules.

You may need to change your Dataset identifiers if they look like a URI, but are used in a less mainstream way, such as relying on the URI's auth section, or have a case-sensitive protocol name.

The method get_permitted_menu_items in BaseAuthManager has been renamed filter_permitted_menu_items (#37627)

Add REST API actions to Audit Log events (#37734)

The Audit Log event name for REST API events will be prepended with api. or ui., depending on if it came from the Airflow UI or externally.

Official support for Python 3.12 (#38025)

There are a few caveats though:

• Pendulum2 does not support Python 3.12. For Python 3.12 you need to use Pendulum 3 <https://pendulum.eustace.io/blog/announcing-pendulum-3-0-0.html>_

• Minimum SQLAlchemy version supported when Pandas is installed for Python 3.12 is 1.4.36 released in April 2022. Airflow 2.9.0 increases the minimum supported version of SQLAlchemy to 1.4.36 for all Python versions.

Not all Providers support Python 3.12. At the initial release of Airflow 2.9.0 the following providers are released without support for Python 3.12:

• apache.beam - pending on Apache Beam support for 3.12 <https://github.com/apache/beam/issues/29149>_
• papermill - pending on Releasing Python 3.12 compatible papermill client version including this merged issue <https://github.com/nteract/papermill/pull/771>_

Prevent large string objects from being stored in the Rendered Template Fields (#38094)

There's now a limit to the length of data that can be stored in the Rendered Template Fields. The limit is set to 4096 characters. If the data exceeds this limit, it will be truncated. You can change this limit by setting the [core]max_template_field_length configuration option in your airflow config.

Change xcom table column value type to longblob for MySQL backend (#38401)

Xcom table column value type has changed from blob to longblob. This will allow you to store relatively big data in Xcom but process can take a significant amount of time if you have a lot of large data stored in Xcom.

To downgrade from revision: b4078ac230a1, ensure that you don't have Xcom values larger than 65,535 bytes. Otherwise, you'll need to clean those rows or run airflow db clean xcom to clean the Xcom table.

New Features

• Allow users to write dag_id and task_id in their national characters, added display name for dag / task (v2) (#38446)
• Prevent large objects from being stored in the RTIF (#38094)
• Use current time to calculate duration when end date is not present. (#38375)
• Add average duration mark line in task and dagrun duration charts. (#38214, #38434)
• Add button to manually create dataset events (#38305)
• Add Matomo as an option for analytics_tool. (#38221)
• Experimental: Support custom weight_rule implementation to calculate the TI priority_weight (#38222)
• Adding ability to automatically set DAG to off after X times it failed sequentially (#36935)
• Add dataset conditions to next run datasets modal (#38123)
• Add task log grouping to UI (#38021)
• Add dataset_expression to grid dag details (#38121)
• Introduce mechanism to support multiple executor configuration (#37635)
• Add color formatting for ANSI chars in logs from task executions (#37985)
• Add the dataset_expression as part of DagModel and DAGDetailSchema (#37826)
• Add TaskFail entries to Gantt chart (#37918)
• Allow longer rendered_map_index (#37798)
• Inherit the run_ordering from DatasetTriggeredTimetable for DatasetOrTimeSchedule (#37775)
• Implement AIP-60 Dataset URI formats (#37005)
• Introducing Logical Operators for dataset conditional logic (#37101)
• Add post endpoint for dataset events (#37570)
• Show custom instance names for a mapped task in UI (#36797)
• Add excluded/included events to get_event_logs api (#37641)
• Add datasets to dag graph (#37604)
• Show dataset events above task/run details in grid view (#37603)
• Introduce new config variable to control whether DAG processor outputs to stdout (#37439)
• Make Datasets hashable (#37465)
• Add conditional logic for dataset triggering (#37016)
• Implement task duration page in react. (#35863)
• Add queuedEvent endpoint to get/delete DatasetDagRunQueue (#37176)
• Support multiple XCom output in the BaseOperator (#37297)
• AIP-58: Add object storage backend for xcom (#37058)
• Introduce DatasetOrTimeSchedule (#36710)
• Add on_skipped_callback to BaseOperator (#36374)
• Allow override of hovered navbar colors (#36631)
• Create new Metrics with Tagging (#36528)
• Add support for openlineage to AFS and common.io (#36410)
• Introduce @task.bash TaskFlow decorator (#30176, #37875)
• Added functionality to automatically ingest custom airflow.cfg file upon startup (#36289)

Improvements

• More human friendly "show tables" output for db cleanup (#38654)
• Improve trigger assign_unassigned by merging alive_triggerer_ids and get_sorted_triggers queries (#38664)
• Add exclude/include events filters to audit log (#38506)
• Clean up unused triggers in a single query for all dialects except MySQL (#38663)
• Update Confirmation Logic for Config Changes on Sensitive Environments Like Production (#38299)
• Improve datasets graph UX (#38476)
• Only show latest dataset event timestamp after last run (#38340)
• Add button to clear only failed tasks in a dagrun. (#38217)
• Delete all old dag pages and redirect to grid view (#37988)
• Check task attribute before use in sentry.add_tagging() (#37143)
• Mysql change xcom value col type for MySQL backend (#38401)
• ExternalPythonOperator use version from sys.version_info (#38377)
• Replace too broad exceptions into the Core (#38344)
• Add CLI support for bulk pause and resume of DAGs (#38265)
• Implement methods on TaskInstancePydantic and DagRunPydantic (#38295, #38302, #38303, #38297)
• Made filters bar collapsible and add a full screen toggle (#38296)
• Encrypt all trigger attributes (#38233, #38358, #38743)
• Upgrade react-table package. Use with Audit Log table (#38092)
• Show if dag page filters are active (#38080)
• Add try number to mapped instance (#38097)
• Add retries to job heartbeat (#37541)
• Add REST API events to Audit Log (#37734)
• Make current working directory as templated field in BashOperator (#37968)
• Add calendar view to react (#37909)
• Add run_id column to log table (#37731)
• Add tryNumber to grid task instance tooltip (#37911)
• Session is not used in _do_render_template_fields (#37856)
• Improve MappedOperator property types (#37870)
• Remove provide_session decorator from TaskInstancePydantic methods (#37853)
• Ensure the "airflow.task" logger used for TaskInstancePydantic and TaskInstance (#37857)
• Better error message for internal api call error (#37852)
• Increase tooltip size of dag grid view (#37782) (#37805)
• Use named loggers instead of root logger (#37801)
• Add Run Duration in React (#37735)
• Avoid non-recommended usage of logging (#37792)
• Improve DateTimeTrigger typing (#37694)
• Make sure all unique run_ids render a task duration bar (#37717)
• Add Dag Audit Log to React (#37682)
• Add log event for auto pause (#38243)
• Better message for exception for templated base operator fields (#37668)
• Clean up webserver endpoints adding to audit log (#37580)
• Filter datasets graph by dag_id (#37464)
• Use new exception type inheriting BaseException for SIGTERMs (#37613)
• Refactor dataset class inheritance (#37590)
• Simplify checks for package versions (#37585)
• Filter Datasets by associated dag_ids (GET /datasets) (#37512)
• Enable "airflow tasks test" to run deferrable operator (#37542)
• Make datasets list/graph width adjustable (#37425)
• Speedup determine installed airflow version in ExternalPythonOperator (#37409)
• Add more task details from rest api (#37394)
• Add confirmation dialog box for DAG run actions (#35393)
• Added shutdown color to the STATE_COLORS (#37295)
• Remove legacy dag details page and redirect to grid (#37232)
• Order XCom entries by map index in API (#37086)
• Add data_interval_start and data_interval_end in dagrun create API endpoint (#36630)
• Making links in task logs as hyperlinks by preventing HTML injection (#36829)
• Improve ExternalTaskSensor Async Implementation (#36916)
• Make Datasets Pathlike (#36947)
• Simplify query for orphaned tasks (#36566)
• Add deferrable param in FileSensor (#36840)
• Run Trigger Page: Configurable number of recent configs (#36878)
• Merge nowait and skip_locked into with_row_locks (#36889)
• Return the specified field when get dag/dagRun in the REST API (#36641)
• Only iterate over the items if debug is enabled for DagFileProcessorManager (#36761)
• Add a fuzzy/regex pattern-matching for metric allow and block list (#36250)
• Allow custom columns in cli dags list (#35250)
• Make it possible to change the default cron timetable (#34851)
• Some improvements to Airflow IO code (#36259)
• Improve TaskInstance typing hints (#36487)
• Remove dependency of Connexion from auth manager interface (#36209)
• Refactor ExternalDagLink to not create ad hoc TaskInstances (#36135)

Bug Fixes

• Load providers configuration when gunicorn workers start (#38795)
• Fix grid header rendering (#38720)
• Add a task instance dependency for mapped dependencies (#37498)
• Improve stability of remove_task_decorator function (#38649)
• Mark more fields on API as dump-only (#38616)
• Fix total_entries count on the event logs endpoint (#38625)
• Add padding to bottom of log block. (#38610)
• Properly serialize nested attrs classes (#38591)
• Fixing the tz in next run ID info (#38482)
• Show abandoned tasks in Grid View (#38511)
• Apply task instance mutation hook consistently (#38440)
• Override chakra styles to keep dropdowns in filter bar (#38456)
• Store duration in seconds and scale to handle case when a value in the series has a larger unit than the preceding durations. (#38374)
• Don't allow defaults other than None in context parameters, and improve error message (#38015)
• Make postgresql default engine args comply with SA 2.0 (#38362)
• Add return statement to yield within a while loop in triggers (#38389)
• Ensure __exit__ is called in decorator context managers (#38383)
• Make the method BaseAuthManager.is_authorized_custom_view abstract (#37915)
• Add upper limit to planned calendar events calculation (#38310)
• Fix Scheduler in daemon mode doesn't create PID at the specified location (#38117)
• Properly serialize TaskInstancePydantic and DagRunPydantic (#37855)
• Fix graph task state border color (#38084)
• Add back methods removed in security manager (#37997)
• Don't log "403" from worker serve-logs as "Unknown error". (#37933)
• Fix execution data validation error in /get_logs_with_metadata endpoint (#37756)
• Fix task duration selection (#37630)
• Refrain from passing encoding to the SQL engine in SQLAlchemy v2 (#37545)
• Fix 'implicitly coercing SELECT object to scalar subquery' in latest dag run statement (#37505)
• Clean up typing with max_execution_date query builder (#36958)
• Optimize max_execution_date query in single dag case (#33242)
• Fix list dags command for get_dagmodel is None (#36739)
• Load consuming_dags attr eagerly before dataset listener (#36247)

Miscellaneous

• Remove display of param from the UI (#38660)
• Update log level to debug from warning about scheduled_duration metric (#38180)
• Use importlib_metadata with compat to Python 3.10/3.12 stdlib (#38366)
• Refactored __new__ magic method of BaseOperatorMeta to avoid bad mixing classic and decorated operators (#37937)
• Use sys.version_info for determine Python Major.Minor (#38372)
• Add missing deprecated Fab auth manager (#38376)
• Remove unused loop variable from airflow package (#38308)
• Adding max consecutive failed dag runs info in UI (#38229)
• Bump minimum version of blinker add where it requires (#38140)
• Bump follow-redirects from 1.15.4 to 1.15.6 in /airflow/www (#38156)
• Bump Cryptography to > 39.0.0 (#38112)
• Add Python 3.12 support (#36755, #38025, #36595)
• Avoid use of assert outside of the tests (#37718)
• Update ObjectStoragePath for universal_pathlib>=v0.2.2 (#37930)
• Resolve G004: Logging statement uses f-string (#37873)
• Update build and install dependencies. (#37910)
• Bump sanitize-html from 2.11.0 to 2.12.1 in /airflow/www (#37833)
• Update to latest installer versions. (#37754)
• Deprecate smtp configs in airflow settings / local_settings (#37711)
• Deprecate PY* constants into the airflow module (#37575)
• Remove usage of deprecated flask._request_ctx_stack (#37522)
• Remove redundant login attribute in airflow.__init__.py (#37565)
• Upgrade to FAB 4.3.11 (#37233)
• Remove SCHEDULED_DEPS which is no longer used anywhere since 2.0.0 (#37140)
• Replace datetime.datetime.utcnow by airflow.utils.timezone.utcnow in core (#35448)
• Bump aiohttp min version to avoid CVE-2024-23829 and CVE-2024-23334 (#37110)
• Move config related to FAB auth manager to FAB provider (#36232)
• Remove MSSQL support form Airflow core (#36514)
• Remove is_authorized_cluster_activity from auth manager (#36175)
• Create FAB provider and move FAB auth manager in it (#35926)

Doc Only Changes

• Improve timetable documentation (#38505)
• Reorder OpenAPI Spec tags alphabetically (#38717)
• Update UI screenshots in the documentation (#38680, #38403, #38438, #38435)
• Remove section as it's no longer true with dataset expressions PR (#38370)
• Refactor DatasetOrTimeSchedule timetable docs (#37771)
• Migrate executor docs to respective providers (#37728)
• Add directive to render a list of URI schemes (#37700)
• Add doc page with providers deprecations (#37075)
• Add a cross reference to security policy (#37004)
• Improve AIRFLOW__WEBSERVER__BASE_URL docs (#37003)
• Update faq.rst with (hopefully) clearer description of start_date (#36846)
• Update public interface doc re operators (#36767)
• Add exception to templates ref list (#36656)
• Add auth manager interface as public interface (#36312)
• Reference fab provider documentation in Airflow documentation (#36310)
• Create auth manager documentation (#36211)
• Update permission docs (#36120)
• Docstring improvement to _covers_every_hour (#36081)
• Add note that task instance, dag and lifecycle listeners are non-experimental (#36376)