Retry Policy

Sometimes tasks fail due to temporary issues such as network errors. Task Orchestrator allows you to automate retry logic for tasks using the built-in RetryPolicy module.

With RetryPolicy, you can configure:

• Max Retries: The maximum number of times a task should be retried.

• Backoff: A function controlling the wait time between retries. The backoff functions are available in pravaha.retry.backoff.

• retry_on: A tuple of exception types. The retry logic will only trigger if the task raises one of these exceptions.

This allows tasks to automatically recover from transient failures without manual intervention.

Example Usage

from pravaha.core.task import Task
from pravaha.retry.policy import RetryPolicy
from pravaha.retry.backoff import fixed_delay
from pravaha.core.executor import TaskExecutor

# Custom exception for demonstration
class ConnectionError(Exception):
    pass

counter = {"value": 0}

@Task(
    name="make_db_connection",
    retries=RetryPolicy(
        max_retries=3,
        backoff=fixed_delay(3),
        retry_on=(ConnectionError,)
    )
)
def make_db_connection():
    if counter['value'] == 2:
        print("Connection made")
        return
    counter['value'] += 1
    raise ConnectionError("Connection error.")

@Task(name="fetch_data_from_db", depends_on=['make_db_connection'])
def fetch_data_from_db():
    print("Fetching data from db.")
    return "Hello world"

@Task(name="print_data", depends_on=['fetch_data_from_db'])
def print_data(data):
    print("Printing data")
    print(data)

if __name__ == '__main__':
    TaskExecutor.execute()

Expected Output

[RETRY] make_db_connection attempt 1, retrying in 3s
[RETRY] make_db_connection attempt 2, retrying in 3s
Connection made
Fetching data from db.
Printing data
Hello world

Notes

• Retry attempts respect the task registration order.

• Backoff functions can be customized (fixed, exponential, or custom functions).

• Only exceptions listed in retry_on trigger retries; other exceptions will fail immediately.