jedarden 8969c44b8b P1.2 Topology type + node state machine - Complete verification

All acceptance criteria met:
- Topology deserializes from plan §4 YAML (RG=2, 6 nodes, RF=2)
- groups() iterator returns RG groups in ascending order
- State-machine tests cover all legal/illegal transitions
- Node::is_write_eligible_for() tests verify correctness table

41 topology tests passing. Implementation complete and verified.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

2026-05-13 18:55:35 -04:00

2.4 KiB

Raw Blame History

P1.2 Topology type + node state machine - Completion Summary

Task

Implement miroir_core::topology with complete state machine and YAML deserialization support.

Implementation Status: ✅ COMPLETE

The topology implementation is fully complete with all acceptance criteria met:

Core Types Implemented

Topology struct with shards, replica_groups, rf, and nodes
Node struct with id, address, replica_group, and status
NodeStatus enum with all required states: Healthy, Degraded, Draining, Failed, Joining, Active, Removed

Helper Methods

✅ Topology::groups() - Returns iterator over all replica groups
✅ Topology::group(g: u32) - Get a specific group by ID
✅ Group::nodes() - Get nodes in a group
✅ Group::healthy_nodes() - Get only healthy nodes in a group

State Machine

Complete state transition validation with all legal transitions:

(new) → Joining (POST /_miroir/nodes)
Joining → Active (Migration complete)
Active → Draining (POST /_miroir/nodes/{id}/drain)
Draining → Removed (Migration complete)
Active/Draining → Failed (Health check detects failure)
Failed → Active (Health check recovery)
Active/Failed ↔ Degraded (Partial health)
Healthy ↔ Active (Bidirectional synonyms)

All illegal transitions are rejected (e.g., Joining → Draining, Removed → Active).

Write Eligibility

Node::is_write_eligible_for(shard_id, status) correctly implements routing eligibility:

Healthy/Active/Degraded: Always eligible
Joining/Failed/Removed: Never eligible
Draining: Eligible only for shards not being actively migrated

Testing

All 41 topology tests pass:

13 state transition tests (legal and illegal)
8 write eligibility tests covering all statuses
4 YAML deserialization tests
16 structural and functional tests

Verification

cargo test topology --lib
# test result: ok. 41 passed; 0 failed; 0 ignored

Files Modified

crates/miroir-core/src/topology.rs - Complete implementation (41 passing tests)

Previous Commits

7aabf62 "P1.2 Topology type + node state machine - Add YAML deserialization test"
Earlier commits in Phase 1 (miroir-cdo) series

Conclusion

The topology implementation is production-ready with comprehensive state machine validation, complete test coverage, and proper YAML deserialization support for the plan §4 configuration format.

2.4 KiB Raw Blame History