Production Ready Clients

Formation client has a few middleware to support production ready clients. Clients that are robust, fail fast and recover from failure in a timely manner.

The idea about formation is to be able to compose and execute a set of middleware on any kind of Python code. In this instance we use both the middleware infrastructure and the HTTP client (for_requests) to show how that can be powerful.

First, the necessary imports:

from formation.for_requests import client, html_response
from formation.middleware import (
    request_logger,
    circuit_breaker,
    trigger_breaker_if,
    timeout,
)
import structlog

logger = structlog.getLogger()

Next, the client and middleware stack:

@client
class Breaker(object):
    base_uri = "https://example.com"
    middleware = [
        timeout(1),
        circuit_breaker(logger, "breaker-1", reset_timeout=10),
        trigger_breaker_if(lambda res: res.status_code == 200),
        request_logger(logger),
    ]
    response_as = html_response

Here, we see that we allow for just one second timeout, for all requests -- timeout(1), we set up a circuit breaker with circuit_breaker in addition to defininf how it should trip with trigger_breaker_if.

Finally we're setting up a structured logger with request_logger.