Cloud Composer 1 | Cloud Composer 2 | Cloud Composer 3
本页面介绍了如何在您的环境中维护 Airflow 数据库。
随着时间的推移，您环境的 Airflow 数据库会存储更多数据， 更多数据。这些数据包括与过往 DAG 运行相关的信息和日志， 任务和其他 Airflow 操作。
准备工作
如果 Airflow 数据库大小超过 16 GB，则无法将环境升级到更高版本。
如果 Airflow 数据库大小超过 20 GB， 因此无法创建快照。
如果您使用 XCom 机制传输文件，请确保按照 Airflow 准则使用该机制。使用 XCom 传输大文件或大量文件会产生以下影响 Airflow 数据库的性能，可能会导致加载失败 快照或升级您的环境请考虑使用如下替代方案 Cloud Storage 来传输大量数据。
按计划运行数据库维护 DAG
您可以使用以下维护 DAG 来剪除 数据库。
请务必定期运行维护 DAG，以将数据库大小保持在 16 GB 以下。对于大多数环境，我们建议每天运行此 DAG。如果您发现数据库大小指标在每次运行之间显著增加，请考虑更频繁地运行此 DAG。
选择一个保留期限（DEFAULT_MAX_DB_ENTRY_AGE_IN_DAYS）
将数据库缓存保持在 16 GB 以下我们建议将时间段
作为大多数环境的起点。
默认情况下，此 DAG 会从 job、dag_run、task_instance、log、xcom、sla_miss、dags、task_reschedule、task_fail 和 import_error 表中移除旧条目。在 DAG 中，查看列表
并决定是否必须从中移除旧条目。在
一般来说，清理 log、task_instance、
dag_run 和 xcom 表。如需从清理中排除某个表，请修改 DAG
并评论 DATABASE_OBJECTS 列表中的对应项。
"""
A maintenance workflow that you can deploy into Airflow to periodically clean
out the DagRun, TaskInstance, Log, XCom, Job DB and SlaMiss entries to avoid
having too much data in your Airflow MetaStore.
## Authors
The DAG is a fork of [teamclairvoyant repository.](
https://github.com/teamclairvoyant/airflow-maintenance-dags/tree/master/db-cleanup
)
## Usage
1. Update the global variables (SCHEDULE_INTERVAL, DAG_OWNER_NAME,
ALERT_EMAIL_ADDRESSES and ENABLE_DELETE) in the DAG with the desired values
2. Modify the DATABASE_OBJECTS list to add/remove objects as needed. Each
dictionary in the list features the following parameters:
- airflow_db_model: Model imported from airflow.models corresponding to
a table in the airflow metadata database
- age_check_column: Column in the model/table to use for calculating max
date of data deletion
- keep_last: Boolean to specify whether to preserve last run instance
- keep_last_filters: List of filters to preserve data from deleting
during clean-up, such as DAG runs where the external trigger is set
to 0.
- keep_last_group_by: Option to specify column by which to group the
database entries and perform aggregate functions.
3. Create and Set the following Variables in the Airflow Web Server
(Admin -> Variables)
- airflow_db_cleanup__max_db_entry_age_in_days - integer - Length to
retain the log files if not already provided in the conf. If this is set
to 30, the job will remove those files that are 30 days old or older.
4. Put the DAG in your gcs bucket.
"""
from datetime import timedelta
import logging
import os
import airflow
from airflow import settings
from airflow.models import (
DAG,
DagModel,
DagRun,
Log,
SlaMiss,
TaskInstance,
Variable,
XCom,
)
from airflow.operators.python import PythonOperator
from airflow.utils import timezone
from airflow.version import version as airflow_version
import dateutil.parser
from sqlalchemy import and_, func, text
from sqlalchemy.exc import ProgrammingError
now = timezone.utcnow
# airflow-db-cleanup
DAG_ID = os.path.basename(__file__).replace(".pyc", "").replace(".py", "")
START_DATE = airflow.utils.dates.days_ago(1)
# How often to Run. @daily - Once a day at Midnight (UTC)
SCHEDULE_INTERVAL = "@daily"
# Who is listed as the owner of this DAG in the Airflow Web Server
DAG_OWNER_NAME = "operations"
# List of email address to send email alerts to if this job fails
ALERT_EMAIL_ADDRESSES = []
# Airflow version used by the environment in list form, value stored in
# airflow_version is in format e.g "2.3.4+composer"
AIRFLOW_VERSION = airflow_version[: -len("+composer")].split(".")
# Length to retain the log files if not already provided in the conf. If this
# is set to 30, the job will remove those files that arE 30 days old or older.
DEFAULT_MAX_DB_ENTRY_AGE_IN_DAYS = int(
Variable.get("airflow_db_cleanup__max_db_entry_age_in_days", 30)
)
# Prints the database entries which will be getting deleted; set to False
# to avoid printing large lists and slowdown process
PRINT_DELETES = False
# Whether the job should delete the db entries or not. Included if you want to
# temporarily avoid deleting the db entries.
ENABLE_DELETE = True
# List of all the objects that will be deleted. Comment out the DB objects you
# want to skip.
DATABASE_OBJECTS = [
{
"airflow_db_model": DagRun,
"age_check_column": DagRun.execution_date,
"keep_last": True,
"keep_last_filters": [DagRun.external_trigger.is_(False)],
"keep_last_group_by": DagRun.dag_id,
},
{
"airflow_db_model": TaskInstance,
"age_check_column": TaskInstance.start_date
if AIRFLOW_VERSION < ["2", "2", "0"]
else TaskInstance.start_date,
"keep_last": False,
"keep_last_filters": None,
"keep_last_group_by": None,
},
{
"airflow_db_model": Log,
"age_check_column": Log.dttm,
"keep_last": False,
"keep_last_filters": None,
"keep_last_group_by": None,
},
{
"airflow_db_model": XCom,
"age_check_column": XCom.execution_date
if AIRFLOW_VERSION < ["2", "2", "5"]
else XCom.timestamp,
"keep_last": False,
"keep_last_filters": None,
"keep_last_group_by": None,
},
{
"airflow_db_model": SlaMiss,
"age_check_column": SlaMiss.execution_date,
"keep_last": False,
"keep_last_filters": None,
"keep_last_group_by": None,
},
{
"airflow_db_model": DagModel,
"age_check_column": DagModel.last_parsed_time,
"keep_last": False,
"keep_last_filters": None,
"keep_last_group_by": None,
},
]
# Check for TaskReschedule model
try:
from airflow.models import TaskReschedule
DATABASE_OBJECTS.append(
{
"airflow_db_model": TaskReschedule,
"age_check_column": TaskReschedule.execution_date
if AIRFLOW_VERSION < ["2", "2", "0"]
else TaskReschedule.start_date,
"keep_last": False,
"keep_last_filters": None,
"keep_last_group_by": None,
}
)
except Exception as e:
logging.error(e)
# Check for TaskFail model
try:
from airflow.models import TaskFail
DATABASE_OBJECTS.append(
{
"airflow_db_model": TaskFail,
"age_check_column": TaskFail.start_date,
"keep_last": False,
"keep_last_filters": None,
"keep_last_group_by": None,
}
)
except Exception as e:
logging.error(e)
# Check for RenderedTaskInstanceFields model
if AIRFLOW_VERSION < ["2", "4", "0"]:
try:
from airflow.models import RenderedTaskInstanceFields
DATABASE_OBJECTS.append(
{
"airflow_db_model": RenderedTaskInstanceFields,
"age_check_column": RenderedTaskInstanceFields.execution_date,
"keep_last": False,
"keep_last_filters": None,
"keep_last_group_by": None,
}
)
except Exception as e:
logging.error(e)
# Check for ImportError model
try:
from airflow.models import ImportError
DATABASE_OBJECTS.append(
{
"airflow_db_model": ImportError,
"age_check_column": ImportError.timestamp,
"keep_last": False,
"keep_last_filters": None,
"keep_last_group_by": None,
"do_not_delete_by_dag_id": True,
}
)
except Exception as e:
logging.error(e)
if AIRFLOW_VERSION < ["2", "6", "0"]:
try:
from airflow.jobs.base_job import BaseJob
DATABASE_OBJECTS.append(
{
"airflow_db_model": BaseJob,
"age_check_column": BaseJob.latest_heartbeat,
"keep_last": False,
"keep_last_filters": None,
"keep_last_group_by": None,
}
)
except Exception as e:
logging.error(e)
else:
try:
from airflow.jobs.job import Job
DATABASE_OBJECTS.append(
{
"airflow_db_model": Job,
"age_check_column": Job.latest_heartbeat,
"keep_last": False,
"keep_last_filters": None,
"keep_last_group_by": None,
}
)
except Exception as e:
logging.error(e)
default_args = {
"owner": DAG_OWNER_NAME,
"depends_on_past": False,
"email": ALERT_EMAIL_ADDRESSES,
"email_on_failure": True,
"email_on_retry": False,
"start_date": START_DATE,
"retries": 1,
"retry_delay": timedelta(minutes=1),
}
dag = DAG(
DAG_ID,
default_args=default_args,
schedule_interval=SCHEDULE_INTERVAL,
start_date=START_DATE,
)
if hasattr(dag, "doc_md"):
dag.doc_md = __doc__
if hasattr(dag, "catchup"):
dag.catchup = False
def print_configuration_function(**context):
logging.info("Loading Configurations...")
dag_run_conf = context.get("dag_run").conf
logging.info("dag_run.conf: " + str(dag_run_conf))
max_db_entry_age_in_days = None
if dag_run_conf:
max_db_entry_age_in_days = dag_run_conf.get("maxDBEntryAgeInDays", None)
logging.info("maxDBEntryAgeInDays from dag_run.conf: " + str(dag_run_conf))
if max_db_entry_age_in_days is None or max_db_entry_age_in_days < 1:
logging.info(
"maxDBEntryAgeInDays conf variable isn't included or Variable "
+ "value is less than 1. Using Default '"
+ str(DEFAULT_MAX_DB_ENTRY_AGE_IN_DAYS)
+ "'"
)
max_db_entry_age_in_days = DEFAULT_MAX_DB_ENTRY_AGE_IN_DAYS
max_date = now() + timedelta(-max_db_entry_age_in_days)
logging.info("Finished Loading Configurations")
logging.info("")
logging.info("Configurations:")
logging.info("max_db_entry_age_in_days: " + str(max_db_entry_age_in_days))
logging.info("max_date: " + str(max_date))
logging.info("enable_delete: " + str(ENABLE_DELETE))
logging.info("")
logging.info("Setting max_execution_date to XCom for Downstream Processes")
context["ti"].xcom_push(key="max_date", value=max_date.isoformat())
print_configuration = PythonOperator(
task_id="print_configuration",
python_callable=print_configuration_function,
provide_context=True,
dag=dag,
)
def build_query(
session,
airflow_db_model,
age_check_column,
max_date,
keep_last,
keep_last_filters=None,
keep_last_group_by=None,
):
query = session.query(airflow_db_model)
logging.info("INITIAL QUERY : " + str(query))
if not keep_last:
query = query.filter(
age_check_column <= max_date,
)
else:
subquery = session.query(func.max(DagRun.execution_date))
# workaround for MySQL "table specified twice" issue
# https://github.com/teamclairvoyant/airflow-maintenance-dags/issues/41
if keep_last_filters is not None:
for entry in keep_last_filters:
subquery = subquery.filter(entry)
logging.info("SUB QUERY [keep_last_filters]: " + str(subquery))
if keep_last_group_by is not None:
subquery = subquery.group_by(keep_last_group_by)
logging.info("SUB QUERY [keep_last_group_by]: " + str(subquery))
subquery = subquery.from_self()
query = query.filter(
and_(age_check_column.notin_(subquery)), and_(age_check_column <= max_date)
)
return query
def print_query(query, airflow_db_model, age_check_column):
entries_to_delete = query.all()
logging.info("Query: " + str(query))
logging.info(
"Process will be Deleting the following "
+ str(airflow_db_model.__name__)
+ "(s):"
)
for entry in entries_to_delete:
date = str(entry.__dict__[str(age_check_column).split(".")[1]])
logging.info("\tEntry: " + str(entry) + ", Date: " + date)
logging.info(
"Process will be Deleting "
+ str(len(entries_to_delete))
+ " "
+ str(airflow_db_model.__name__)
+ "(s)"
)
def cleanup_function(**context):
session = settings.Session()
logging.info("Retrieving max_execution_date from XCom")
max_date = context["ti"].xcom_pull(
task_ids=print_configuration.task_id, key="max_date"
)
max_date = dateutil.parser.parse(max_date) # stored as iso8601 str in xcom
airflow_db_model = context["params"].get("airflow_db_model")
state = context["params"].get("state")
age_check_column = context["params"].get("age_check_column")
keep_last = context["params"].get("keep_last")
keep_last_filters = context["params"].get("keep_last_filters")
keep_last_group_by = context["params"].get("keep_last_group_by")
logging.info("Configurations:")
logging.info("max_date: " + str(max_date))
logging.info("enable_delete: " + str(ENABLE_DELETE))
logging.info("session: " + str(session))
logging.info("airflow_db_model: " + str(airflow_db_model))
logging.info("state: " + str(state))
logging.info("age_check_column: " + str(age_check_column))
logging.info("keep_last: " + str(keep_last))
logging.info("keep_last_filters: " + str(keep_last_filters))
logging.info("keep_last_group_by: " + str(keep_last_group_by))
logging.info("")
logging.info("Running Cleanup Process...")
try:
if context["params"].get("do_not_delete_by_dag_id"):
query = build_query(
session,
airflow_db_model,
age_check_column,
max_date,
keep_last,
keep_last_filters,
keep_last_group_by,
)
if PRINT_DELETES:
print_query(query, airflow_db_model, age_check_column)
if ENABLE_DELETE:
logging.info("Performing Delete...")
query.delete(synchronize_session=False)
session.commit()
else:
dags = session.query(airflow_db_model.dag_id).distinct()
session.commit()
list_dags = [str(list(dag)[0]) for dag in dags] + [None]
for dag in list_dags:
query = build_query(
session,
airflow_db_model,
age_check_column,
max_date,
keep_last,
keep_last_filters,
keep_last_group_by,
)
query = query.filter(airflow_db_model.dag_id == dag)
if PRINT_DELETES:
print_query(query, airflow_db_model, age_check_column)
if ENABLE_DELETE:
logging.info("Performing Delete...")
query.delete(synchronize_session=False)
session.commit()
if not ENABLE_DELETE:
logging.warn(
"You've opted to skip deleting the db entries. "
"Set ENABLE_DELETE to True to delete entries!!!"
)
logging.info("Finished Running Cleanup Process")
except ProgrammingError as e:
logging.error(e)
logging.error(
str(airflow_db_model) + " is not present in the metadata." + "Skipping..."
)
finally:
session.close()
def cleanup_sessions():
session = settings.Session()
try:
logging.info("Deleting sessions...")
count_statement = (
"SELECT COUNT(*) AS cnt FROM session WHERE expiry < now()::timestamp(0);"
)
before = session.execute(text(count_statement)).one_or_none()["cnt"]
session.execute(text("DELETE FROM session WHERE expiry < now()::timestamp(0);"))
after = session.execute(text(count_statement)).one_or_none()["cnt"]
logging.info("Deleted %s expired sessions.", (before - after))
except Exception as err:
logging.exception(err)
session.commit()
session.close()
def analyze_db():
session = settings.Session()
session.execute("ANALYZE")
session.commit()
session.close()
analyze_op = PythonOperator(
task_id="analyze_query", python_callable=analyze_db, provide_context=True, dag=dag
)
cleanup_session_op = PythonOperator(
task_id="cleanup_sessions",
python_callable=cleanup_sessions,
provide_context=True,
dag=dag,
)
cleanup_session_op.set_downstream(analyze_op)
for db_object in DATABASE_OBJECTS:
cleanup_op = PythonOperator(
task_id="cleanup_" + str(db_object["airflow_db_model"].__name__),
python_callable=cleanup_function,
params=db_object,
provide_context=True,
dag=dag,
)
print_configuration.set_downstream(cleanup_op)
cleanup_op.set_downstream(analyze_op)
移除未使用的 DAG 的条目
如需移除未使用的 DAG 的数据库条目，请执行以下操作： 从 Airflow 网页界面中移除 DAG。