f/data.py
Greg Pomerantz cba7291676 data: manifest-based incremental refresh of the parquet cache
The cache now tracks every file in the data dir (mtime_ns + size) in
.cache/manifest.json. On load, a directory scan is compared against the
manifest:
  - changed/added files are re-read and merged into the parquet panels
    (one read + one concat + one write per touched panel; new values
    win where present, old values kept where the new file is short)
  - removed files drop their symbols (and names)
  - an up-to-date cache is a ~30 ms memo hit

Measured on the real 4k-symbol set: full build 54 s, refresh of
5 modified + 1 added + 1 removed files 3.4 s. No scan TTL (a scan is
a few ms); a previous 5 s scan cache masked data updates.

Tests: tests/test_data.py (11 checks) added as step 1 of run_tests.sh.
2026-08-24 17:28:20 -04:00

283 lines
10 KiB
Python

"""Data ingestion: Yahoo Finance CSV dumps -> parquet cache.
Layout expected in the data root (default ~/prog/fin/stocks):
{SYM}-history.csv Date,Open,High,Low,Close,Adj Close,Volume
{SYM}-dividend.csv Date,Dividends (optional)
{SYM}-capitalGain.csv Date,Capital Gains (optional)
{SYM}.json Yahoo chart API payload (metadata only)
All panels are date x symbol DataFrames. The "adj" panel (Adj Close)
already bakes in dividends and capital gains, so it is the correct
input for pre-tax total returns. The dividend/capgain panels are used
only by the tax engine (to tax distributions).
First call builds a parquet cache (default: .cache/) in ~1 min for
4k symbols; subsequent calls load in well under a second.
"""
from __future__ import annotations
import json
import os
import threading
from dataclasses import dataclass
from pathlib import Path
import pandas as pd
DEFAULT_ROOT = Path("~/prog/fin/stocks").expanduser()
CACHE_DIR = Path(__file__).parent / ".cache"
_SUFFIXES = ("history", "dividend", "capitalGain")
_PANELS = ("adj", "close", "div", "capg")
@dataclass
class Bundle:
adj: pd.DataFrame # adjusted close (total-return adjusted)
close: pd.DataFrame # raw close
div: pd.DataFrame # dividend distributions per share
capg: pd.DataFrame # capital gain distributions per share
names: dict # symbol -> long name (best effort)
def _read_csv_clean(f: Path) -> pd.DataFrame:
df = pd.read_csv(f, index_col=0)
df.index = pd.to_datetime(df.index, format="mixed", errors="coerce")
df = df[~df.index.isna()]
df = df[~df.index.duplicated(keep="last")].sort_index()
return df
def _read_panel(root: Path, suffix: str, col: str) -> pd.DataFrame:
cols, syms = [], []
for f in sorted(root.glob(f"*-{suffix}.csv")):
try:
df = _read_csv_clean(f)
except Exception:
continue
if col in df.columns:
cols.append(df[col])
syms.append(f.name[: -len(f"-{suffix}.csv")])
if not cols:
return pd.DataFrame()
out = pd.concat(cols, axis=1)
out.columns = syms
return out.sort_index()
def _read_name(f: Path) -> str:
try:
meta = json.loads(f.read_text())["chart"]["result"][0]["meta"]
return meta.get("longName", f.stem)
except Exception:
return f.stem
def _read_names(root: Path, max_files: int = 5000) -> dict:
files = sorted(root.glob("*.json"))[:max_files]
return {f.stem: _read_name(f) for f in files}
# ---------------------------------------------------------------- caching
# a bundle is ~2 GB resident; memoize the last one so Streamlit re-runs
# (every widget change!) don't reload the parquet panels
_BUNDLE_CACHE: dict[tuple, Bundle] = {}
_LOCK = threading.Lock()
def _scan_files(root: Path) -> dict:
"""{filename: (mtime_ns, size)} for every csv/json file in the data root."""
out = {}
with os.scandir(root) as it:
for e in it:
if e.is_file() and e.name.endswith((".csv", ".json")):
st = e.stat()
out[e.name] = (st.st_mtime_ns, st.st_size)
return out
def _manifest_path(cache: Path) -> Path:
return cache / "manifest.json"
def _cache_up_to_date(root: Path, cache: Path) -> bool:
"""Cheap staleness check: dir scan vs manifest.
A scan is a handful of milliseconds for ~16k files, so this is done on
every call (caching the scan result would mask data updates)."""
new = _scan_files(root)
try:
old = json.loads(_manifest_path(cache).read_text())
except Exception:
return False
return {f: tuple(v) for f, v in old.items()} == new
def _full_build(root: Path, cache: Path, cache_files: list) -> None:
"""(Re)read every CSV and write all parquet panels + manifest."""
adj = _read_panel(root, "history", "Adj Close")
close = _read_panel(root, "history", "Close")
div = _read_panel(root, "dividend", "Dividends").fillna(0.0)
capg = _read_panel(root, "capitalGain", "Capital Gains").fillna(0.0)
for df, f in zip((adj, close, div, capg), cache_files):
df.to_parquet(f)
_manifest_path(cache).write_text(json.dumps(_scan_files(root)))
def _apply_changes(root: Path, cache: Path, old: dict, new: dict) -> None:
"""Incremental refresh: re-read only files that were added/changed,
drop symbols whose files vanished, refresh names, rewrite the touched
parquet panels.
Per touched panel this is ONE read + ONE concat + ONE write (inserting
column-by-column into a ~500 MB frame is prohibitively slow).
"""
old = {f: tuple(v) for f, v in old.items()} # JSON round-trip turns tuples into lists
changed = [f for f, v in new.items() if old.get(f) != v]
removed = [f for f in old if f not in new]
if not changed and not removed:
return
def _suffix(fname: str):
for sfx in _SUFFIXES:
if fname.endswith(f"-{sfx}.csv"):
return sfx, fname[: -len(f"-{sfx}.csv")]
return None, None
updates: dict[str, dict] = {k: {} for k in _PANELS} # panel -> {sym: series}
drops: set[str] = set()
for fname in changed:
sfx, sym = _suffix(fname)
if sfx is None:
continue
try:
df = _read_csv_clean(root / fname)
except Exception:
continue # e.g. a file mid-download
if sfx == "history":
if "Adj Close" in df.columns:
updates["adj"][sym] = df["Adj Close"]
if "Close" in df.columns:
updates["close"][sym] = df["Close"]
elif sfx == "dividend" and "Dividends" in df.columns:
updates["div"][sym] = df["Dividends"].fillna(0.0)
elif sfx == "capitalGain" and "Capital Gains" in df.columns:
updates["capg"][sym] = df["Capital Gains"].fillna(0.0)
for fname in removed:
sfx, sym = _suffix(fname)
if sfx is not None:
drops.add(sym)
# names: only the json metadata files that changed
j_changed = [f for f in changed if f.endswith(".json")]
j_removed = [f for f in removed if f.endswith(".json")]
if j_changed or j_removed:
names_path = cache / "names.json"
try:
names = json.loads(names_path.read_text())
except Exception:
names = {}
for f in j_removed:
names.pop(f[:-5], None)
for f in j_changed:
names[f[:-5]] = _read_name(root / f)
names_path.write_text(json.dumps(names))
for k in _PANELS:
upd = {s: ser for s, ser in updates[k].items() if s not in drops}
if not upd and not drops:
continue
panel = pd.read_parquet(cache / f"panel_{k}.parquet")
old = {s: panel[s] for s in upd if s in panel.columns}
drop_cols = [s for s in (drops | set(upd)) if s in panel.columns]
if drop_cols:
panel = panel.drop(columns=drop_cols)
if upd:
extras = []
for sym, s in upd.items():
s = s.rename(sym)
if sym in old:
# new values win where present; keep old values for dates
# the new file doesn't cover (e.g. a partial re-download)
uidx = panel.index.union(s.index)
s = s.reindex(uidx).combine_first(old[sym].reindex(uidx))
extras.append(s)
extra = pd.concat(extras, axis=1)
extra.columns = list(upd)
panel = pd.concat([panel, extra], axis=1).sort_index()
panel.to_parquet(cache / f"panel_{k}.parquet")
def load_bundle(root: Path = DEFAULT_ROOT, cache: Path = CACHE_DIR,
rebuild: bool = False) -> Bundle:
"""Load the full dataset, using (or building) a parquet cache.
The cache tracks the data dir via a manifest of (mtime, size) per file:
changed/added files are re-read and merged in incrementally, removed
files are dropped, so an updated download refreshes in seconds instead
of the ~1 min full rebuild. `rebuild=True` forces the full rebuild.
"""
root, cache = Path(root), Path(cache)
key = (str(root), rebuild)
with _LOCK:
hit = _BUNDLE_CACHE.get(key)
if hit is not None and not rebuild and _cache_up_to_date(root, cache):
return hit
cache.mkdir(parents=True, exist_ok=True)
cache_files = [cache / f"panel_{k}.parquet" for k in _PANELS]
cache_ok = all(f.exists() for f in cache_files)
if rebuild or not cache_ok:
_full_build(root, cache, cache_files)
else:
try:
old = json.loads(_manifest_path(cache).read_text())
except Exception:
old = None
new = _scan_files(root)
if old is None:
# parquet without a manifest: state unknown -> rebuild once
_full_build(root, cache, cache_files)
else:
_apply_changes(root, cache, old, new)
_manifest_path(cache).write_text(json.dumps(new))
panels = {k: pd.read_parquet(f) for k, f in zip(_PANELS, cache_files)}
names_path = cache / "names.json"
if names_path.exists():
names = json.loads(names_path.read_text())
else:
names = _read_names(root)
names_path.write_text(json.dumps(names))
bundle = Bundle(panels["adj"], panels["close"], panels["div"],
panels["capg"], names)
# keep only the newest bundle: there is no room for two
_BUNDLE_CACHE.clear()
_BUNDLE_CACHE[key] = bundle
return bundle
def search_symbols(bundle: Bundle, query: str, limit: int = 200) -> list[str]:
"""Case-insensitive search over symbols and names.
Ranked: exact symbol, symbol prefix, name prefix, symbol substring,
name substring.
"""
q = query.lower()
buckets: dict[int, list[str]] = {}
for s in bundle.adj.columns:
sl, nl = s.lower(), bundle.names.get(s, "").lower()
if sl == q:
buckets.setdefault(0, []).append(s)
elif sl.startswith(q):
buckets.setdefault(1, []).append(s)
elif nl.startswith(q):
buckets.setdefault(2, []).append(s)
elif q in sl:
buckets.setdefault(3, []).append(s)
elif q in nl:
buckets.setdefault(4, []).append(s)
out: list[str] = []
for k in sorted(buckets):
out.extend(buckets[k])
return out[:limit]