Paulo Fidalgo
Writing
Essays and technical notes from engineering leadership, Rails, testing, infrastructure, and open-source work.
Rails
Service objects, boundaries, and tests in Rails
Service objects are useful when they make a boundary clearer. They become noise when they only move code without improving the system.
Technical Note
Branch coverage for changed Ruby code
Global coverage numbers can hide the risk in the change under review. A branch-focused SimpleCov group makes review more concrete.
Engineering Practice
Commit messages are engineering documents
Commit messages preserve intent, tradeoffs, and operational memory. They are part of the engineering record, not administrative noise.
Technical Note
Docker and SELinux on Fedora
A practical Fedora note for keeping SELinux enabled while making Docker storage, mounted workspaces, and container networking behave.
Rails
Rails, PostgreSQL, and UUID primary keys
UUID primary keys are useful when independent generation, merge safety, or public identifier opacity matters. They are not a default upgrade.
Technical Note
Load testing with Ruby and JMeter
An older note on defining JMeter load-test scenarios in Ruby and running them headlessly with repeatable output.
Open Source
Debugging a Padrino routing bug
A small framework bug became a focused contribution by isolating the behavior, writing the failing expectation, and sending a narrow fix.