Spring - MongoDB migrations (Mongock)
Apply Mongock migration guidelines for Spring Boot and Spring Data MongoDB.
What is covered in this Skill?
- Mongock BOM, Spring Boot runner, and Spring Data MongoDB driver coordinates
mongock.migration-scan-package configuration and startup execution- Code-first
@ChangeUnit migrations with @Execution and rollback hooks
- Locking, idempotency, transaction limits, and forward-only rollout discipline
- Optional MongoDB-backed integration tests using only project-approved, pinned, or already-available container images when the user permits external runtime dependencies
- Coordination with
@315-frameworks-spring-mongodb
Scope: Apply recommendations based on the reference rules and good/bad examples.
Constraints
Compile before Mongock or MongoDB migration changes; verify after changes.
- MANDATORY: Run
./mvnw compile or mvn compile before applying any change
- SAFETY: If compilation fails, stop immediately
- VERIFY: Run
./mvnw clean verify or mvn clean verify after applying improvements
- BEFORE APPLYING: Read the reference for detailed rules and good/bad patterns
- EDGE CASE: If the project Spring Data MongoDB version is not compatible with the selected Mongock driver, stop and ask whether to pin/upgrade Mongock or use a lower driver generation
- EXTERNAL RUNTIME GATE: Do not pull or execute Docker images for MongoDB verification unless the user explicitly approves and the image is pinned, policy-approved, or already present in the project configuration
When to use this skill
- Add Mongock migrations in Spring Boot
- Review Spring MongoDB data migrations
- Configure Mongock change units for Spring Data MongoDB
- Create Mongock change units for Spring Boot MongoDB
- Review Mongock migration ordering in a Spring service
Workflow
- Read references and inspect MongoDB setup
Read references/316-frameworks-spring-mongodb-migrations-mongock.md, references/316-frameworks-spring-mongodb-migrations-mongock-antipatterns.md, and references/316-frameworks-spring-mongodb-migrations-mongock-parallel-change.md, then inspect pom.xml, Spring Boot version, dependency management, MongoDB configuration, existing full-context tests, and existing @315-frameworks-spring-mongodb persistence patterns.
- Choose runner, driver, and execution policy
Select Mongock coordinates compatible with the active Spring Data MongoDB generation, configure migration scan packages, and decide startup vs controlled-job execution.
- Apply framework-aligned migrations
Implement/refactor @ChangeUnit classes with idempotent operations, explicit ordering, rollback hooks, and safe lock/transaction settings.
- Run verification and report results
Execute build/tests. Run MongoDB-backed migration checks only when the project already defines an approved MongoDB test runtime or the user explicitly approves a pinned container image. If generic @SpringBootTest smoke tests do not provide MongoDB, disable Mongock only for those tests with mongock.enabled=false. Summarize outcomes and follow-up risks.
Reference
For detailed guidance, examples, and constraints, see: