Skip to main content

Simple retry client for aiohttp

Project description

Simple aiohttp retry client

codecov

Python 3.6 or higher.

Install: pip install aiohttp-retry.

Warning

This current version is 2.0+. It hasn't backward compatibility for previous versions.
You still can use v1.2 (pip install aiohttp-retry==1.2), but it is unsupported.

Examples of usage:

from aiohttp_retry import RetryClient, ExponentialRetry

async def main():
    retry_options = ExponentialRetry(attempts=1)
    retry_client = RetryClient(raise_for_status=False, retry_options=retry_options)
    async with retry_client.get('https://ya.ru') as response:
        print(response.status)

    await retry_client.close()
from aiohttp_retry import RetryClient, RandomRetry

async def main():
    retry_options = RandomRetry(attempts=1)
    retry_client = RetryClient(raise_for_status=False, retry_options=retry_options)

    response = await retry_client.get('/ping')
    print(response.status)

    await retry_client.close()
from aiohttp_retry import RetryClient

async def main():
    async with RetryClient() as client:
        async with client.get('https://ya.ru') as response:
            print(response.status)

You can also add some logic, F.E. logging, on failures by using trace mechanic.

import logging
import sys
from types import SimpleNamespace

from aiohttp import ClientSession, TraceConfig, TraceRequestStartParams

from aiohttp_retry import RetryClient, ExponentialRetry


handler = logging.StreamHandler(sys.stdout)
logging.basicConfig(handlers=[handler])
logger = logging.getLogger(__name__)
retry_options = ExponentialRetry(attempts=2)


async def on_request_start(
    session: ClientSession,
    trace_config_ctx: SimpleNamespace,
    params: TraceRequestStartParams,
) -> None:
    current_attempt = trace_config_ctx.trace_request_ctx['current_attempt']
    if retry_options.attempts <= current_attempt:
        logger.warning('Wow! We are in last attempt')


async def main():
    trace_config = TraceConfig()
    trace_config.on_request_start.append(on_request_start)
    retry_client = RetryClient(retry_options=retry_options, trace_configs=[trace_config])

    response = await retry_client.get('https://httpstat.us/503', ssl=False)
    print(response.status)

    await retry_client.close()

Look tests for more examples.
Be aware: last request returns as it is.

Documentation

RetryClient takes the same arguments as ClientSession[docs]
RetryClient has methods:

  • get
  • options
  • head
  • post
  • put
  • patch
  • put
  • delete

They are same as for ClientSession, but take one possible additional argument:

class RetryOptionsBase:
    def __init__(
        self,
        attempts: int = 3,  # How many times we should retry
        statuses: Optional[Iterable[int]] = None,  # On which statuses we should retry
        exceptions: Optional[Iterable[Type[Exception]]] = None,  # On which exceptions we should retry
    ):
        ...

    @abc.abstractmethod
    def get_timeout(self, attempt: int) -> float:
        raise NotImplementedError

You can specify RetryOptions both for RetryClient and it's methods. RetryOptions in methods override RetryOptions defined in RetryClient constructor.

You can define your own timeouts logic or use:

  • ExponentialRetry with exponential backoff
  • RandomRetry for random backoff
  • ListRetry with backoff you predefine by list

Request Trace Context

RetryClient add current attempt number to request_trace_ctx (see examples, for more info see aiohttp doc).

Change URL between retries

You can change URL between retries by specifying url as list of urls. Example:

from aiohttp_retry import RetryClient

retry_client = RetryClient()
async with retry_client.get(url=['/internal_error', '/ping']) as response:
    text = await response.text()
    assert response.status == 200
    assert text == 'Ok!'

await retry_client.close()

In this example we request /interval_error, fail and then successfully request /ping. If you specify less urls than attempts number in RetryOptions, RetryClient will request last url at last attempts. This means that in example above we would request /ping once again in case of failure.

Project details


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

aiohttp_retry-2.3.5.tar.gz (5.3 kB view hashes)

Uploaded Source

Built Distribution

aiohttp_retry-2.3.5-py3-none-any.whl (6.5 kB view hashes)

Uploaded Python 3

Supported by

AWS AWS Cloud computing and Security Sponsor Datadog Datadog Monitoring Fastly Fastly CDN Google Google Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page