architecture

  • An aggregate that was three aggregates in a trench coat

    A Subscription class of nine hundred lines, holding the plan, the billing schedule and the usage record, loaded in full to check whether a feature was enabled. The…

  • A cache with persistence turned on to hide a design problem

    Turning on persistence so a restart would stop losing data, which is treating the symptom of data that should not have been there. Persistence on a cache is…

  • The service we merged back

    Two services extracted in 2021, a team of four maintaining four pipelines, and forty-one of forty-four releases touching both.

  • Rate limiting per key rather than per address

    A limit keyed on the client address, and four integrators behind one corporate gateway sharing a quota. Keying on the credential is the only fair unit when consumers…

  • Reusable workflows, and the inputs that became an API

    A reusable workflow shared across four repositories, and the eleventh input added because one repository was different. Every input is a branch in the workflow and eleven of…

  • A sparse fieldset that was invented by accident

    A response that omits fields when a header is present, implemented three years ago for one consumer and never documented. The behaviour was correct and the mechanism was…

  • The migration Rector wrote and we rewrote

    An automated refactor across 412 files, a diff of 8,000 lines, and three wrong hunks in it. The review nobody could actually do.

  • Layer rules after a merge, and the baseline that grew

    Merging two codebases produced a layer rule baseline of 188 violations, where each had been under five. A baseline that jumps is nearly always a configuration problem rather…

  • Include parameters, and the query language they become

    An include parameter added for one consumer, and eleven values later it is a query language with no grammar. An include parameter is a small query language and…

  • Cache keys audited for what writes them

    An audit of every cache key, asking one question each: if this disappeared, could it be regenerated? A cache that holds the only copy of something is a…