An array of one or more matching conditions in the form of APISIX expressions. The buffered logs are flushed to the error log only when all expressions evaluate to true. When unset, the logs are collected for every request.

Probability of collecting the logs for a request. The default value of 1 collects the logs for all requests. Set to a value below 1 to collect the logs for a random sample of requests.

Maximum number of log entries held in the per-worker buffer. When the number of buffered logs exceeds this value, the oldest entries are overwritten.