# Service Locator Pattern

> A design pattern in which code fetches its dependencies from a global registry at the point of use.

Record: `architecture:service-locator-pattern`
Kind: pattern
Layer: [Extensibility Core](https://banes-lab.com/records/layer/extensibility-core.md)
Severity: discouraged
Scope: runtime, dependency access
Canonical: https://banes-lab.com/ontology#architecture-service-locator-pattern

Listed in [Architecture principles](https://banes-lab.com/api/records/architecture.md), after [Registry Pattern](https://banes-lab.com/records/architecture/registry-pattern.md) and before [Feature Toggle](https://banes-lab.com/records/architecture/feature-toggle.md).

## Repair

- Refactored by: Replace with Dependency Injection
- Detected by: service locator calls inside domain logic
- Violated by: hidden dependencies through global locator
- Measured by: hidden dependency count
- Enforced by: banned API rules

## Requires

- [Registry](https://banes-lab.com/records/lexicon/registry.md)

## Reinforces

- [Runtime Lookup](https://banes-lab.com/records/lexicon/runtime-lookup.md)

## Enables

- [Late Resolution](https://banes-lab.com/records/lexicon/late-resolution.md)

## In tension with

- [Testability](https://banes-lab.com/records/architecture/testability.md)
- [Dependency Inversion Principle (DIP)](https://banes-lab.com/records/architecture/dependency-inversion.md)
- [Explicit Dependencies](https://banes-lab.com/records/lexicon/explicit-dependencies.md)

## Tensions

- [Service Locator Pattern / Testability](https://banes-lab.com/records/tension/service-locator-pattern-testability.md)
- [Service Locator Pattern / Dependency Inversion Principle (DIP)](https://banes-lab.com/records/tension/dependency-inversion-principle-dip-service-locator-pattern.md)
- [Service Locator Pattern / Explicit Dependencies](https://banes-lab.com/records/tension/explicit-dependencies-service-locator-pattern.md)

## Severity

- [discouraged](https://banes-lab.com/records/vocabulary/severity-discouraged.md)

## Category

- [Plugin / Extensibility / IoC](https://banes-lab.com/records/architecture-category/plugin-extensibility-ioc.md)

## Linked from

- [Correctness / Determinism / Verification](https://banes-lab.com/ontology/principles/architecture-category-correctness-determinism-verification.md)
- [SOLID / Object-Oriented Design](https://banes-lab.com/ontology/principles/architecture-category-solid-object-oriented-design.md)
- [Plugin / Extensibility / IoC](https://banes-lab.com/ontology/lexicon/lexicon-category-plugin-extensibility-ioc.md)
- [Severity levels](https://banes-lab.com/ontology/schema/the-vocabulary-severity.md)
- [The resolutions](https://banes-lab.com/ontology/schema/the-resolutions.md)