Implement cursor repository

[pragmaticAweds]

Repository

This issue belongs in Fundable-Protocol/Backend under indexer/.

Migrated from https://github.com/Fundable-Protocol/stellar_indexer/issues/7.

Context

Cursor table access should be isolated behind a repository so poller logic does not spread SQL details through the codebase.

Scope

• Add get cursor behavior
• Add initialize cursor behavior
• Add update cursor behavior
• Add tests for normal and missing cursor cases

Out of Scope

• Unrelated package work
• Docker, CI, or deployment work unless named in scope
• Broad refactors outside the touched package

Acceptance Criteria

• Scope items are complete
• Relevant tests are added or updated
• Documentation is updated when needed
• bun run type-check passes
• bun run test passes
• bun run lint passes
• bun run indexer:type-check passes
• bun run indexer:test passes
• bun run indexer:lint passes

Dependencies

• Create core ledger cursor table #24

Suggested Files or Packages

• indexer/common/src/db/
• indexer/common/src/index.ts

[Franklivania]

@Franklivania has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hi, I am Franklin. I have built backend infrastructure around repository patterns, isolating persistence logic from business services to improve maintainability, testing, and scalability. I have implemented similar database repositories for blockchain indexers and event-processing systems, including cursor management, atomic updates, and comprehensive test coverage for stateful workflows.

To tackle this issue, I would:

• Implement a dedicated cursor repository under indexer/common/src/db/ to encapsulate all cursor-related database operations.

• Add repository methods for retrieving, initializing, and updating cursor state while keeping SQL implementation details isolated from the poller logic.

• Handle missing cursor scenarios gracefully by supporting initialization and predictable return values.

• Ensure cursor updates are atomic and safe for long-running indexer processes.

• Export the repository through indexer/common/src/index.ts where appropriate for consistent consumption across the indexer package.

• Add unit and integration tests covering:

  • Successful cursor retrieval.
  • Missing cursor initialization.
  • Cursor updates.
  • Edge cases around absent or newly created cursor records.

• Update documentation if needed and verify the implementation by running:

  • bun run type-check
  • bun run test
  • bun run lint
  • bun run indexer:type-check
  • bun run indexer:test
  • bun run indexer:lint

ETA: 6–8 hours.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Franklivania to this issue.

[drips-wave]

Congratulations, @Franklivania! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

🧑‍💻 @Franklivania: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

🤠 Repo maintainers: Please keep an eye on the contributor's progress and review their work before the due date. You can manage this issue, including adjusting its complexity and points, here.

🌊 Happy Wave 🌊

[Franklivania]

@pragmaticAweds , waiting for PR #41 to be merged, so I can work on this, as I am dependent on it