aiohttp-retry 2.2

Simple retry cient for aiohttp

Simple aiohttp retry client

This package is similar to Tornado-retry-client.
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, RetryOptions

async def main():
    retry_options = RetryOptions(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, RetryOptions

async def main():
    retry_options = RetryOptions(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, RetryOptions


handler = logging.StreamHandler(sys.stdout)
logging.basicConfig(handlers=[handler])
logger = logging.getLogger(__name__)
retry_options = RetryOptions(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:

from typing import Optional, Set, Type

class RetryOptions:
    def __init__(
        self,
        attempts: int = 3,  # How many times we should retry
        start_timeout: float = 0.1,  # Base timeout time, then it exponentially grow
        max_timeout: float = 30.0,  # Max possible timeout between tries
        factor: float = 2.0,  # How much we increase timeout each time
        statuses: Optional[Set[int]] = None,  # On which statuses we should retry
        exceptions: Optional[Set[Type[Exception]]] = None,  # On which exceptions we should retry
    )
    ...

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

Request Trace Context

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