id: T042 name: CreditService - Credit/Quota Management goal: Implement PROJECT.md Item 13 - project-based resource usage and billing management status: complete priority: P1 owner: peerA (spec), peerB (impl) created: 2025-12-11 depends_on: [] blocks: [] context: | **PROJECT.md Item 13: CreditService** - プロジェクトごとのリソース使用量と課金を管理する「銀行」のようなサービス - 各サービス（PlasmaVMCなど）からのリソース作成リクエストをインターセプトして残高確認（Admission Control） - NightLightから使用量メトリクスを収集して定期的に残高を引き落とす（Billing Batch） **Architecture Decision (2025-12-11):** - IAMにクオータ管理を持たせず、専用のCreditServiceを新設 - NightLightを使用量計測のバックエンドとして活用 acceptance: - Wallet/Balance management per project - gRPC Admission Control API for resource creation checks - NightLight integration for usage metrics - Billing batch process for periodic deductions - Multi-tenant isolation (project scoped) steps: - step: S1 name: Research and Specification done: spec.md with API design, data model, integration points status: complete owner: peerA priority: P0 outputs: - path: specifications/creditservice/spec.md note: Full specification (~400L) notes: | Completed: - IAM Scope model analysis (ProjectScope with org_id) - NightLight integration design (PromQL queries) - 2-phase commit admission control pattern - ChainFire/FlareDB storage options Deliverables: - specifications/creditservice/spec.md (complete) - gRPC proto design (in spec) - Data model: Wallet, Transaction, Reservation, Quota - step: S2 name: Workspace Scaffold done: creditservice workspace with types, proto, api, server crates status: complete owner: peerB priority: P0 outputs: - path: creditservice/crates/creditservice-types/ note: Core types (Wallet, Transaction, Reservation, Quota, Error) - path: creditservice/crates/creditservice-proto/ note: gRPC proto generation - path: creditservice/crates/creditservice-api/ note: Service implementation stubs - path: creditservice/crates/creditservice-server/ note: Server binary - path: creditservice/creditservice-client/ note: Client library notes: | **Complete (2025-12-11):** - 5 crates created and building (cargo check OK) - creditservice-types: ~400L (Wallet, Transaction, Reservation, Quota, Error) - creditservice-proto: build.rs + proto generation - creditservice-api: CreditServiceImpl with all method stubs - creditservice-server: Server binary with health service - creditservice-client: Client library with convenience methods - step: S3 name: Core Wallet Management done: Wallet CRUD, balance operations, transaction log status: complete owner: peerB priority: P0 outputs: - path: creditservice/crates/creditservice-api/src/storage.rs note: CreditStorage trait + InMemoryStorage (~190L) - path: creditservice/crates/creditservice-api/src/credit_service.rs note: gRPC service with wallet methods (~450L) notes: | **Complete (2025-12-11):** - CreditStorage trait abstraction for wallet/transaction/reservation/quota ops - InMemoryStorage implementation with RwLock-based concurrency - Implemented gRPC methods: get_wallet, create_wallet, top_up, get_transactions - Proto-to-domain type conversions (Wallet, Transaction, WalletStatus) - Error mapping (storage errors to gRPC Status codes) - 7 unit tests passing (storage + service layer) - step: S4 name: Admission Control API done: gRPC service for resource creation checks status: complete owner: peerA priority: P0 outputs: - path: creditservice/crates/creditservice-api/src/credit_service.rs note: Admission Control methods (~250L added) notes: | **Complete (2025-12-11) by PeerA:** - check_quota: Balance + quota validation, returns allowed/denied with reason - reserve_credits: 2-phase commit phase 1, creates reservation with TTL - commit_reservation: Phase 2, deducts from wallet, logs transaction - release_reservation: Releases held credits back to available balance - set_quota/get_quota/list_quotas: Quota CRUD operations - Proto conversion helpers for Quota, Reservation, ResourceType - 7 new tests passing (total 14 tests for creditservice-api) - step: S5 name: NightLight Integration done: Usage metrics collection from NightLight status: complete owner: peerA priority: P1 outputs: - path: creditservice/crates/creditservice-api/src/nightlight.rs note: NightLightClient (~420L) notes: | **Complete (2025-12-11) by PeerA:** - NightLightClient implementing UsageMetricsProvider trait - PromQL queries for all 10 ResourceTypes - list_projects_with_usage() for batch billing discovery - Health check endpoint - 4 new tests passing - step: S6 name: Billing Batch done: Periodic billing process with configurable intervals status: complete owner: peerB priority: P1 outputs: - path: creditservice/crates/creditservice-api/src/billing.rs note: Billing module (~200L) - path: creditservice/crates/creditservice-api/src/credit_service.rs note: process_billing method + process_project_billing helper notes: | **Complete (2025-12-11) by PeerB:** - UsageMetricsProvider trait for metrics abstraction - MockUsageMetricsProvider for testing - PricingRules with default pricing per resource type - process_billing gRPC method implementation - Batch processing with per-project results - Wallet suspension on zero/negative balance - 3 new tests (21 total for creditservice-api) evidence: - cmd: "cargo test" result: "21 tests passing (creditservice-api)" notes: | **T042 COMPLETE (2025-12-11)** - Total: ~2,500L across 6 steps - All acceptance criteria met: - Wallet/Balance management per project ✓ - gRPC Admission Control API ✓ - NightLight integration ✓ - Billing batch process ✓ - Multi-tenant isolation (project scoped) ✓ - 21 tests in creditservice-api + 2 in creditservice-types = 23 tests total