Airflow how to retry task
Airflow how to retry task. BaseOperator | None) – email_alert (exception, task) [source] ¶ Send alert email with exception information. 10. See Schedule DAGs in Airflow; Automatically retry tasks In Airflow, you can configure individual tasks to retry automatically in case of a failure. Depending on the task's configuration, Airflow can retry the task, skip it, or mark it as failed. models. I managed it to retry the start_job task using the on_failure_callback of the wait_for_job sensor task. Oct 11, 2019 · I know that it is possible to retry individual tasks, but is it possible to retry complete DAG? I create tasks dynamically, that is why I need to retry not specific task, but complete DAG. Important Notes Apr 21, 2019 · retry_delay (timedelta) – delay between retries; retry_exponential_backoff (bool) – allow progressive longer waits between retries by using exponential backoff algorithm on retry delay (delay will be converted into seconds) max_retry_delay (timedelta) – maximum delay interval between retries How can I define Operators that can decide if a retry is sensible? In Airflow 1. amazonaws. their process was killed, or the machine died). on_skipped_callback. Jun 1, 2015 · If it deduces that it is allow to retry again retries < max_retries-1 and the state is failed, it will change its state, add 1 to retries, and pass the instruction to the executor. Original point: on_success_callback / on_failure_callback: Depending of whether Task 2 is supposed to run upon success or failure of Task 1, you can pass lambda: time. Invoked right before the task begins executing. At the third retry it will either mark the task as success if no exception was present or failed if there was an exception. This SO post suggests using the GUI to "clear" failed task: How to restart a failed task on Airflow. Second, clearing (rerun) a TaskGroup is a feature that currently is not available. email. But that is not running for 5 times. Apr 28, 2022 · I have a DAG which contains two tasks. Issue. execution_date, reverse=True) dag_run = dag_runs_sorted[0] task_run = dag_run. Then, you'll want to optionally clear downstream tasks as well and set the state of the relevant DagRun to running. You can mark the tasks the same as if they were not done ("Clear the state") and make them queued to be re-run. You should treat tasks in Airflow equivalent to transactions in a database. We’ll also provide some tips on how to troubleshoot failed tasks and keep your DAGs running smoothly. For example: task1 >> task2 Which would run task1 first, wait for it to complete, and only then run task2. Here's a deep dive into how retries work in Airflow and how to configure them effectively. AirflowFailException will mark the current task as failed ignoring any remaining retry attempts Apr 7, 2017 · If you want to rerun all the subtasks of the failed tasks, there is an easier way than the accepted answer especially if you have multiple tasks you want to rerun. Can a failed Airflow DAG Task Retry with changed parameter Sep 21, 2022 · Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright Feb 2, 2018 · The operator has set retries and retry_delay. Airflow retries are a fundamental feature that allows tasks to be re-executed in case of failures, ensuring that transient issues don't cause a pipeline to fail permanently. Airflow will find these periodically, clean them up, and either fail or retry the task depending on its settings. If you could provide some samples that's be great. Task F - Generate reports. There is an open feature request for it in When the previous (previous to EmailOperator) task fails, and is marked as, State: failed, the last task (EmailOperator) is then shown as yellow in the UI up_for_retry, but is marked in the logs as, State: upstream_failed. taskinstance. Mar 5, 2019 · UPDATE-1. Task timeout for Airflow DAGs. Invoked when the task is up for retry. For one of the tasks, I want to retry it 5 times in case of failure in airflow. After that it tries to run the task and then fall back to new retry time. Oct 20, 2020 · In my Airflow DAG i have 4 tasks. Best Practices Clearing a task instance creates a record of the task instance. Essentially, for any exit code other that 0, airflow will retry the task on the basis of retry value configured. We advise against using dynamic start_date and recommend using fixed ones Aug 8, 2022 · To fix your problem you can try: from airflow. But you can call a bash command as part of your on_failure_callback and then specify which tasks you want to clear, and if you want downstream/upstream tasks cleared etc. Hitting this will clear the state of your failed task and allow the scheduler to pick it back up and re-run it. 9 in celery executor mode. If it fails I'd start the "Start Spark cluster" task. Oct 19, 2021 · First, In Airflow downstream task can not effect upstream task. This also allows passing a list: Oct 1, 2023 · Image your DAG runs every day at midnight but the files from sources A, B, and C, never come. When the task is scheduled, it will check the database to see if the sign-off is done: If the sign-off has not been done yet, the task fails and release the worker and wait for next schedule. This doesn't seem to be supported. Apache Airflow tasks are stuck in a 'up_for_retry' state. python import PythonOperator def check_task_failure_count(dag_id, task_id): """ Returns the number of times a task has failed in the last dag run Args: dag_id (str): The dag_id to check task_id (str): The task_id to check Jan 16, 2019 · Task A - Gather the raw data. Invoked when a task misses its defined SLA. Not In Retry Period Task is not ready for retry yet but will be retried automatically. If task A depends on task B and their start_date are offset in a way that their execution_date don’t line up, A’s dependencies will never be met. Creating a task. Our task instances are stuck in retry mode. Maybe it's my unfamiliartiy with python or airflow in general, but could someone gu Jun 24, 2022 · Hi I'm currently running airflow on a Dataproc cluster. Click on the failed task in the Tree or Graph views and then click on Clear. Thereafter, you can retrieve that data from Xcom in any task across any DAG of your Airflow deployment, including the retry attempt of same / different task Invoked when the task succeeds. Parameters. email import send_email from airflow. on_retry_callback. set_duration [source] ¶ Set task instance duration. Jun 11, 2018 · You can run a second "Fail Check" DAG that queries for any task instances where the task_id matches what you want and the state is failed using the provide_session util. The default number of times a task will retry before failing permanently can be defined at the Airflow configuration level using the core config default_task_retries. My DAGs used to run fine but facing this issue where tasks are ending up in 'retry' state without any logs when I click on task instance -> Dec 3, 2019 · Currently, there is no way to set retry at dag level. Feb 8, 2019 · I have retry logic for tasks and it's not clear how Airflow handles task failures when retries are turned on. If you are looking to delay a task, for example running a daily task at 2AM, look into the TimeSensor and TimeDeltaSensor. execute() is called. operators. Invoked when the task is running and [email] email_backend = airflow. TaskInstance. May 2, 2019 · The BranchPythonOperator is much like the PythonOperator except that it expects a python_callable that returns a task_id (or list of task_ids). Oct 16, 2022 · Let's say we have two DAGs, each containing only one task: DAG A : Task A (produces data, runs manually) DAG B : Task B (consumes hourly data, runs hourly) DAG B runs may fail because hourly data that Task B has to consume is not available yet (not produced by Task A yet). Please refer the below answer for retrying a set of tasks/whole-dag in case of failures. I fixed the bug that caused some tasks to fail and I would like to re-run ONLY FAILED TASKS. 6, the logic that decides if a task should be retried or not is in airflow. It should retry, or at least trigger on_failure_callback to let me know it failed. Feb 2, 2024 · Exponentially increase the delay between task retries. Jul 19, 2019 · If you want to re-run a task in Airflow, the best way to do so is to press Clear or Delete (language depends on the Airflow version you’re running), not Run. Proper timeout handling ensures that your workflows remain robust and predictable, even in the face of unexpected delays or failures. When a task should be retried, it's marked in state up_for_retry. So the task will be rescheduled after it fails. Airflow’s built-in retry mechanism is useful, but it often makes sense to exponentially increase the delay between the tries instead of from airflow. Then, you should set retry_upstream_depth as 2. Dec 27, 2018 · I have a Apache Airflow DAG with tens of thousands of tasks and after a run, say a handful of them failed. Task E - Process Job results. db import create_session def rerun_dag_task(dag_name, task_name): dag_runs = DagRun. If task D fails because of parameter x being too high, I want to rerun task C and task D. Here are some other ways of introducing delay. on_execute_callback. Also, the maximum number of running tasks for that DAG is limited to 12 (max_active_tasks_per_dag=12). In that case, we should wait for DAG A to run again before retrying Task B. Airflow ExternalTaskSensor execution timeout. If the job doesn't complete within the configured sensor timeout, the job failed and I want both the start_job and the wait_for_job task to be re-tried. it can not change the state of taskB to failed. Aug 8, 2018 · In my Airflow DAG I have a task that needs to know if it's the first time it's ran or if it's a retry run. Why does a task with upstream_failed get assigned to up_for_retry or at least in this specific Jan 10, 2014 · Task Instance Details Dependencies Blocking Task From Getting Scheduled Dependency Reason Task Instance State Task is in the 'up_for_retry' state which is not a valid state for execution. The order of your tasks is as follows: task_1 >> task_2 >> task_depends_on_previous_tasks And you want to retry task_1 and task_2 sequentially when task_depends_on_previous_tasks fails. I need to adjust my logic in the task if it's a retry attempt. Invoked when the task fails. region. Below is info from Airflow documentation Mar 6, 2022 · from airflow import DAG from airflow. g. find(dag_id=dag_name) dag_runs_sorted = sorted(dag_runs, key=lambda dr: dr. Here is my code. dedent ("""\ #### Load task A simple Load task which takes in the result of the Transform task, by reading it from xcom and instead of saving it to end Jul 21, 2021 · I have a dag with multiple tasks. Context is the same dictionary used as when rendering jinja templates. Here’s a basic example DAG: It defines four Tasks - A, B, C, and D - and dictates the order in which they have to run, and which tasks depend on what others. If it is not supported by Airflow, maybe there is some workaround. How to reproduce it:. How do i set a condition such as : if task_2 fails, retry task_2 after 2 minutes and stop retrying after the 5th attempt Mar 11, 2024 · A sensor task (wait_for_job) waits for the job to complete. Feb 13, 2019 · You can make use of on_failure_callback and on_retry_callback params of BaseOperator to push the value that you want to persist as xcom. What I'm getting is key: return_value ; Value:ODAwMAo=. An example is not to produce incomplete data in HDFS or S3 at the end of a task. The try_number of the current task instance is incremented, the max_tries set to 0 and the state set to None, which causes the task to re-run. Dec 12, 2018 · I resorted to reading the source code, and found that Airflow treats up_for_retry tasks differently if they are part of a backfill DAG run. 7. doc_md = textwrap. send_email_smtp [smtp] # If you want airflow to send emails on retries, failure, and you want to use # the airflow. UPDATE: do NOT use this as pointed out by @Vit. Dec 4, 2020 · How to use a different retry delay in every Airflow task Bartosz Mikulski 04 Dec 2020 – 1 min read When we configure an Airflow DAG, we set the default values of various properties, for example, the retry delay. The task must be cleared in order to be run. task_1 >> [task_2,task_3]>> task_4 task_4 runs only after a successful run of both task_2 and task_3. See full list on stackabuse. Task D - Run the data manipulation Job. First state: Task is not ready for retry yet but will be retried automatically. For other failures I do not want to retry. handle_failure, making it impossible to define the behavior in the operator as it is a responsibility of the task and not the operator. If this service becomes unavailable during the task execution, I would like to retry later (max 3 retries). Delete a running worker pod then you'll see: kubectl delete pods -n airflow airflow-worker-3 --force @PhilippJohannis thanks for this, I changed xcom_push argument in my SSHOperator to do_xcom_push. Nov 17, 2021 · In Airflow, you can define order between tasks using >>. baseoperator. 8. com When a task fails, Airflow can automatically retry it based on the parameters defined in the task's configuration. Airflow started running the stuck task immediately. Execute right before self. Feb 21, 2019 · You could use the execution_timeout argument when creating the task to control how long it'll run before timing out. So I connected to the metadata DB and changed backfill_ to scheduled__ in the dag_run row corresponding to the stuck task. The expected scenario is the following: Task 1 executes If Task 1 succeed, then execute Task 2a Else If Task 1 This computed value is then put into xcom, so that it can be processed by the next task. def build_task(self, dag): Jun 26, 2019 · What's the best way to retry an Airflow operator only for certain failures/exceptions? For example, let's assume that I have an Airflow task which relies on the availability of an external service. I'm using Airflow but didn't find a way to trigger a task in case the previous one fails. Jul 19, 2021 · Regarding the retry logic: If you specify retries=3 as keyword-argument to your BaseOperator, it will retry 3 times. Apr 26, 2017 · In the DAGs screen you can see the running tasks: Example. send_email_smtp function, you have to configure an # smtp server here smtp_host = emailsmtpserver. On 'Recent Tasks' press the running icon and Airflow will automatically run the search query with the filters for the Dag Id and State equal to 'running' and show the results on the Task Instances screen (you can find it manually on the tab Browse > Task Instances). Alternatively, if retries == max_retries - 1 the scheduler will set the status of the Task to failed, notify that the task has failed, and not retry the task. sleep(300) in either of these params of Task 1. This functionality is crucial for handling transient issues that can occur in distributed systems, such as temporary network outages or resource unavailability. Airflow can retry a task if it fails. abstract execute (context) [source] ¶. exceptions import AirflowFailException def task_to_fail(): raise AirflowFailException("Our api key is bad!") If you are looking for retries use AirflowException :- Example:- May 22, 2018 · if sp. The executor will re-run it. May 16, 2023 · Here are some examples of different wait intervals between retries to illustrate how long the scheduler will wait to re-schedule a task for a retry: retries retry_delay Dec 23, 2021 · Is there any difference between the following ways for handling Airflow tasks failure? First way - def handle_failure(**kwargs): do_something(kwargs) def on_failure_callback(context): A DAG (Directed Acyclic Graph) is the core concept of Airflow, collecting Tasks together, organized with dependencies and relationships to say how they should run. The Dag has been created like below: default_args = { 'catchup': False, 'depends_on_past': False, 'start_date': datetime(2022, 1 When a task times out, it's essential to handle the exception appropriately. 13. Task B - Generate config file for job. The task_id returned by the Python function has to be referencing a task directly downstream from the BranchPythonOperator task. I have a few ideas on how I Airflow detects two kinds of task/process mismatch: Zombie tasks are tasks that are supposed to be running but suddenly died (e. When a task in Airflow fails, the system can automatically retry the task based on the retry parameters defined in the task's configuration. Derive when creating an operator. Aug 29, 2018 · We are running airflow version 1. returncode: raise AirflowException("Bash command failed") This indicates that unless exit code is 0, airflow will mark the task as failed for all other exit codes. BaseOperator) – task related to the exception. sla_miss_callback. get_task_instance(task_id=task_name) with create_session() as session: clear_task_instances(tis=[task_run Jul 6, 2021 · What you expected to happen:. For example. This implies that you should never produce incomplete results from your tasks. Apache Airflow's retry mechanism is a fundamental feature that ensures the robustness of data pipeline execution. Feb 27, 2018 · Then for my task that runs subdagoperator, it has: on_retry_callback=callback_subdag_clear, It now clears out the task instance history of each task and re-runs each task in the sub dag up to the number of retries in the main dag. If you want to control your task’s state from within custom Task/Operator code, Airflow provides two special exceptions you can raise: AirflowSkipException will mark the current task as skipped. task (airflow. Their documentation just states that on_failure_callback gets triggered when a task fails, but if that task fails and is also marked for retry does that mean that both the on_failure_callback and on_retry_callback would be called? DAG scheduling. Task C - Modify config file parameter x. pre_execute (context) [source] ¶. Checking the xcom page, I'm not getting the expected result. """) load_task = PythonOperator (task_id = "load", python_callable = load,) load_task. exception – the exception. Besides that I'd need to check the previous one in case it succeeds so it would branch to the Spark job task and skip the "Start Spark Cluster" task. Feb 28, 2020 · As other comments mentioned, I would use caution to make sure you aren't getting into an endless loop of clearing/retries. com smtp_starttls = True smtp_ssl = False # Uncomment and May 16, 2017 · I need to be able to access default_args defined as part of DAG definition in a Python Operator, python_callable. Apr 28, 2017 · I would like to create a conditional task in Airflow as described in the schema below. Dec 26, 2023 · In this article, we’ll discuss how to retry tasks in Airflow, including the different retry strategies available and how to configure them. models import DagRun from airflow. on_failure_callback. When the job fails, the task instance retries. Assuming structure of: taskA >> taskB >> taskC >> taskD then if taskB is successful and taskC failed. utils. Aug 14, 2019 · You can change n to control how many tasks you want to retry before the current task. The task_id returned is followed, and all of the other paths are skipped. By default it will also clear downstream tasks recursively, but you can change that with the option selections. ai. So if you run your task at 7AM, and want it to end at 9AM, then set the timeout to 2 hours. nuoc axnu bbej cmrns ebnjb jgtq yfohvu adcp zptdrja dbyxxw