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logging

  • A correlation id that survives a language boundary

    Note1 min read

    Two services generating their own request identifiers means two traces for one request and no way to connect them. Deciding where the identifier originates is the whole conversation,…

  • An SLO that survived contact with the business

    Deep dive14 min read

    99.9% was written in a document in 2020 and had never been measured. Three teams with three definitions of “up”.

  • A multi-window alert stops firing when it recovers

    Note1 min read

    A long window detects a sustained problem and keeps firing for hours after it ends, which trains people to ignore the alert. The long window is doing the…

  • Model events lie about who made the change

    Note2 min read

    An ORM observer sees that a row changed and has no idea who changed it or why, so it invents an actor from whatever ambient context exists. The…

  • A job summary is markdown you write to a file

    Note2 min read

    A pipeline that reports its result by making somebody open the log is a pipeline whose result nobody reads. Writing the failure explanation into the summary rather than…

  • An incident channel that is created, not chosen

    Note2 min read

    Deciding where to coordinate during an incident is a decision made badly under pressure, and automating the creation removes it. The timeline being captured automatically is the part…

  • An audit record needs before, after and an actor

    Note2 min read

    A log line saying that an order was updated answers none of the questions asked during a dispute. Recording only the changed fields rather than the whole model…

  • Exemplars link a metric to a trace

    Note1 min read

    A latency histogram tells you the 99th percentile is four seconds and cannot tell you which request that was, and an exemplar attaches a trace id to a…

  • An audit log that a lawyer could read

    Deep dive9 min read

    A dispute, and a log that recorded that something changed. “Order updated” with no before, no after and no actor.

  • An error boundary catches renders and not event handlers

    Note2 min read

    An error boundary catches errors thrown during rendering, in lifecycle methods and in constructors, and nothing thrown from a click handler or a promise. Handlers and promises need…