Türker Yıldırım

logging

  • try/catch around await catches a rejection

    Note2 min read

    A rejected promise inside an async function behaves like a thrown exception, which means error handling stops being a .catch() bolted onto the end of a chain and…

  • A circuit breaker before the third-party outage

    Deep dive10 min read

    A payment provider was slow and the whole site went down with it. A timeout bounds one request; it does nothing about how many are waiting at once.

  • journald rate limiting drops your logs silently

    Note1 min read

    systemd-journald discards messages from a service exceeding its burst limit and notes the fact in a single line that is easy to miss — so a debugging session…

  • Alerting that people do not learn to ignore

    Deep dive10 min read

    340 alerts in a month, four of which mattered. An alert channel nobody reads is the same as no alerting, and the cause is alerting on causes.

  • Delete Elasticsearch indices older than 30 days

    Snippet1 min read

  • Logging drivers, and why json-file fills the disk

    Note1 min read

    The default driver writes every line to a JSON file with no rotation, so a chatty container quietly consumes the host disk and nothing points at it —…

  • Centralised logging that answers a question

    Deep dive17 min read

    Four servers, eleven log files, and an incident reconstructed from three of them. Shipping first and parsing second, structured events, and the correlation id that makes it useful.

  • Every threshold needs a duration

    Note2 min read

    An alert on an instantaneous value fires on the spike that a deploy, a cron job or a single slow request produces, so the first thing anyone does…

  • The runbook link belongs in the alert

    Note1 min read

    An alert saying HighErrorRate on shop-web at three in the morning is a puzzle. The person receiving it may not have written the check, and the context lives…

  • Structured logs are the whole decision

    Note2 min read

    A log line written as a sentence has to be parsed back into fields by a regular expression somebody maintains, and that expression breaks whenever the sentence changes.…