Files
foxhunt/crates/ml/src/feature_cache.rs
2026-04-01 01:37:59 +02:00

93 lines
3.2 KiB
Rust

//! Feature Cache Key Utilities
//!
//! Provides cache key generation for `.fxcache` auto-discovery.
//! The flat-binary `.fxcache` format is the only cache path; Parquet
//! and old binary caches have been removed.
use anyhow::{Context, Result};
use sha2::{Digest, Sha256};
use std::path::{Path, PathBuf};
use std::time::SystemTime;
/// Calculate a cache key for a DBN data directory.
///
/// Hashes every `.dbn` and `.dbn.zst` file found recursively under `data_dir`
/// by (canonical path, size, mtime). Any change to the directory contents
/// (add / remove / modify) produces a different key.
pub fn calculate_dbn_cache_key(data_dir: &Path) -> Result<String> {
calculate_dbn_cache_key_full(data_dir, None, None)
}
/// Extended cache key that includes MBP-10 and trades directories.
/// The cache is invalidated when ANY data source changes — OHLCV, MBP-10, or trades.
/// Without this, a cache built without trades would serve stale features
/// even after trades data is added, silently dropping VPIN/Kyle's Lambda enrichment.
pub fn calculate_dbn_cache_key_full(
data_dir: &Path,
mbp10_dir: Option<&Path>,
trades_dir: Option<&Path>,
) -> Result<String> {
let mut hasher = Sha256::new();
hasher.update(data_dir.to_string_lossy().as_bytes());
let mut files: Vec<_> = collect_dbn_files_for_hash(data_dir);
// Also include MBP-10 and trades files in the hash
if let Some(dir) = mbp10_dir {
hasher.update(b"mbp10:");
hasher.update(dir.to_string_lossy().as_bytes());
files.extend(collect_dbn_files_for_hash(dir));
} else {
hasher.update(b"mbp10:none");
}
if let Some(dir) = trades_dir {
hasher.update(b"trades:");
hasher.update(dir.to_string_lossy().as_bytes());
files.extend(collect_dbn_files_for_hash(dir));
} else {
hasher.update(b"trades:none");
}
files.sort(); // deterministic ordering
if files.is_empty() {
return Err(anyhow::anyhow!(
"No .dbn or .dbn.zst files found in {:?} — cannot build cache key",
data_dir
));
}
for path in &files {
hasher.update(path.to_string_lossy().as_bytes());
let meta = path
.metadata()
.with_context(|| format!("Failed to stat {:?}", path))?;
hasher.update(&meta.len().to_le_bytes());
let mtime = meta
.modified()
.context("mtime unavailable")?
.duration_since(SystemTime::UNIX_EPOCH)
.context("mtime before epoch")?
.as_secs();
hasher.update(&mtime.to_le_bytes());
}
Ok(format!("{:x}", hasher.finalize()))
}
/// Collect all .dbn and .dbn.zst paths recursively (for hashing purposes).
fn collect_dbn_files_for_hash(dir: &Path) -> Vec<PathBuf> {
let mut out = Vec::new();
if let Ok(entries) = std::fs::read_dir(dir) {
for entry in entries.flatten() {
let path = entry.path();
if path.is_dir() {
out.extend(collect_dbn_files_for_hash(&path));
} else if path.extension().and_then(|s| s.to_str()) == Some("dbn")
|| path.to_string_lossy().ends_with(".dbn.zst")
{
out.push(path);
}
}
}
out
}