How deeply does Python Concurrency with asyncio cover closed state?

Defines normal operation, failure counting, and reopening after a reset interval while skipping detailed half-open behavior.

Closed state

As explained in Python Concurrency with asyncio

The closed state is the circuit-breaker state in which requests are sent normally to the protected service.

The closed state is the circuit breaker's normal path: requests reach the protected service, and successful responses return normally. It contrasts with the open state, which fails calls immediately after repeated service errors. section 10.3.5

A simple circuit breaker uses the closed state to:

Send requests normally while failures remain below the configured limit. section 10.3.5
Record failures within a time window and open the circuit after the maximum is exceeded. section 10.3.5

Breaker in action

A slow callback times out twice, causing the circuit to open; subsequent calls fail fast. After five seconds, the circuit closes and requests resume until failures trip it again.

How Python Concurrency with asyncio covers it

Cover of Python Concurrency with asyncio

liveBook manning.com

Read Python Concurrency with asyncio on liveBook Get the book at manning.com

Related concepts

circuit breaker patternpart of · The circuit breaker pattern is a resilience mechanism that temporarily interrupts or limits operations when specified failure or risk conditions occur, often allowing controlled recovery attempts.
open statecontrasts with · An open state is a circuit-breaker state in which calls to a failing dependency are rejected or fail immediately without being attempted.
half-open statecontrasts with · A half-open state is a circuit-breaker state that permits a limited number of requests to test whether a previously failing dependency has recovered.

This explainer was generated by Manning's knowledge graph from the text of Python Concurrency with asyncio. The section links point to the parts of the book it draws on.