MES-719: Local Caching

[markovejnovic]

No description provided.

[mesa-dot-dev]

Mesa Description

This PR introduces a local, file-based caching layer to improve file read performance and reduce network traffic to the Mesa API.

Key Changes

• New Caching Library (lib/cache):

  • A new, reusable cache library was created to house all caching logic.
  • Introduced FileCache, a thread-safe, asynchronous file-based cache for storing arbitrary byte data.
  • Implemented an asynchronous LRU (Least Recently Used) eviction strategy to manage the cache's size on disk, ensuring it doesn't grow indefinitely.

• Filesystem Integration:

  • The RepoFs module, which handles file system operations for individual repositories, is now equipped with the FileCache.
  • The read operation was updated to follow a cache-aside pattern: it first attempts to retrieve file content from the local cache. On a cache miss, it fetches the content from the Mesa API and then stores it in the cache for subsequent requests.

• Configuration and Testing:

  • Cache behavior is now configurable, with settings passed down from the main daemon configuration.
  • Comprehensive correctness and concurrency tests were added for both the FileCache implementation and the underlying LRU eviction logic to ensure reliability under load.

^{Description generated by Mesa. Update settings}

[mesa-dot-dev]

Performed full review of d6db315...26ecc80

Analysis

1. The caching library relies on nightly-only Rust features but doesn't enable all necessary unstable gates, making it incompilable on both stable and nightly.

2. The FileCache implementation always wipes the target directory on initialization, preventing cache persistence across restarts and undermining the purpose of a file-backed cache.

3. Eviction operations mix synchronous filesystem calls in async workers without proper blocking isolation, risking runtime stalls during large batch evictions.

4. The architecture splits caching into a separate crate, but the integration has inconsistencies that may impact production usability.

Tip

Help

Slash Commands:

• /review - Request a full code review
• /review latest - Review only changes since the last review
• /describe - Generate PR description. This will update the PR body or issue comment depending on your configuration
• /help - Get help with Mesa commands and configuration options

^{0 files reviewed | 1 comments | Edit Agent Settings • Read Docs}