Module manager 

High-level orchestrator combining the cache, index, and rotator.

AssetManager is the entry point used by the rest of devboy-tools. It hides the split between the physical cache directory and the in-memory index, and enforces the rotation policy on every write.

Concurrency and blocking

The manager wraps its mutable state in a std::sync::Mutex so it can be freely cloned via an Arc (e.g. to be shared across tokio tasks). The mutex serializes updates to the in-memory AssetIndex and rotation bookkeeping: reads, writes, touches, rotation, and index persistence all synchronize through the same critical section.

Several code paths also perform filesystem I/O while holding the lock, including:

• AssetManager::get — is_file() existence check on the target file before returning the metadata
• AssetManager::delete — CacheManager::delete on the target file
• AssetManager::store — rotation may delete evicted files, and AssetIndex::save writes index.json atomically (temp file + rename)
• AssetManager::rotate_now — same rotation + persist path

The only filesystem write that intentionally runs before the lock is acquired is the initial CacheManager::store inside AssetManager::store, which writes the new blob to a path derived from the caller-supplied asset_id and filename. Assuming the caller provides unique asset_id values (which is part of the API contract), two concurrent writes target different paths and cannot collide. Reusing the same asset_id concurrently is unsupported and may race on the underlying file.

Because of the above, callers must not assume these methods are free from blocking filesystem work — if they are invoked from an async context, wrap them in tokio::task::spawn_blocking (or equivalent) so the executor’s worker thread isn’t stalled on disk I/O.

Structs

AssetManager

Top-level asset cache.

ResolvedAsset

Resolved lookup result — both the cached metadata and the absolute path of the file on disk.

StoreRequest

Parameters for AssetManager::store.