aljaz/cdk

mirror of https://github.com/aljazceru/cdk.git synced 2025-12-18 21:25:09 +01:00

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# Implement Saga Pattern for Swap Operations with Recovery Mechanism

## Overview

This PR refactors the swap operation implementation to use the saga pattern - a distributed transaction pattern that provides reliable transaction management through explicit state tracking and compensation-based error handling. The implementation includes a robust recovery mechanism that automatically handles swap operations interrupted by crashes, power loss, or network failures.

## What Changed

**Saga Pattern Implementation:**
- Introduced a strict linear state machine for swaps: `Initial` → `SetupComplete` → `Signed` → `Completed`
- New modular `swap_saga` module with state validation, compensation logic, and saga orchestration
- Automatic rollback of database changes on failure, ensuring atomic swap operations
- Replaced previous swap implementation (`swap.rs`, `blinded_message_writer.rs`) with saga-based approach

**Recovery Mechanism:**
- Added `operation_id` and `operation_kind` columns to database schema for tracking which operation proofs belong to
- New `recover_from_bad_swaps()` method that runs on mint startup to handle incomplete swaps
- For proofs left in `PENDING` state from swap operations:
  - If blind signatures exist: marks proofs as `SPENT` (swap completed but not finalized)
  - If no blind signatures exist: removes proofs from database (swap failed partway through)
- Database migrations included for both PostgreSQL and SQLite

2025-10-22 08:30:33 -05:00

src

Swap saga (#1183 )

2025-10-22 08:30:33 -05:00

tests

Migrate from sqlx to rusqlite (#783 )

2025-06-14 12:49:50 +01:00

Cargo.toml

Prometheus crate (#883 )

2025-09-09 13:26:03 +01:00

README.md

chore: update readmes (#773 )

2025-05-29 09:38:10 -04:00

README.md

CDK SQLite

ALPHA This library is in early development, the API will change and should be used with caution.

SQLite storage backend implementation for the Cashu Development Kit (CDK).

Features

The following crate feature flags are available:

Feature	Default	Description
`wallet`	Yes	Enable cashu wallet features
`mint`	Yes	Enable cashu mint wallet features
`sqlcipher`	No	Enable encrypted database

Installation

Add this to your Cargo.toml:

[dependencies]
cdk-sqlite = "*"

Minimum Supported Rust Version (MSRV)

This crate supports Rust version 1.75.0 or higher.

To build and test with the MSRV you will need to pin the below dependency versions:

cargo update -p half --precise 2.2.1
cargo update -p home --precise 0.5.5
cargo update -p tokio --precise 1.38.1
cargo update -p serde_with --precise 3.1.0
cargo update -p reqwest --precise 0.12.4

License

This project is licensed under the MIT License.