The Solution: Configuration Externalization Pattern

The problems in the last lesson share one cause. The values live inside the artifact. The Configuration Externalization Pattern separates the two.

What the Pattern Says

The rule is short. Settings are stored outside the deployable artifact, and the service reads them when it runs.

That is the whole idea. Everything below is a consequence of it.

The values are held in one place instead of sixty. That place is usually a configuration server, which is a service whose only job is to hold settings and hand them out. For a small system, a file in a shared location does the same job.