ad/molodetz/database/settings.py

# retoor <retoor@molodetz.nl>
import logging

from molodetz.cache import TTLCache
from molodetz.constants import SETTINGS_DEFAULTS
from molodetz.database.core import db, now_iso

logger = logging.getLogger(__name__)

_settings_cache = TTLCache(ttl=60, max_size=100)
_version_cache = TTLCache(ttl=1, max_size=100)
_local_versions = {}


def read_cache_version(name):
    cached = _version_cache.get(name)
    if cached is not None:
        return cached
    try:
        if "cache_state" not in db.tables:
            return 0
        row = db["cache_state"].find_one(name=name)
        version = int(row["version"]) if row else 0
    except Exception as exc:
        logger.warning("cache version read failed for %s: %s", name, exc)
        return 0
    _version_cache.set(name, version)
    return version


def sync_local_cache(name, cache):
    version = read_cache_version(name)
    if _local_versions.get(name) != version:
        cache.clear()
        _local_versions[name] = version


def bump_cache_version(name, cache=None):
    try:
        with db:
            db.query(
                "INSERT INTO cache_state (name, version, updated_at) VALUES (:name, 1, :stamp) "
                "ON CONFLICT(name) DO UPDATE SET version = version + 1, updated_at = excluded.updated_at",
                name=name,
                stamp=now_iso(),
            )
    except Exception as exc:
        logger.warning("cache version bump failed for %s: %s", name, exc)
    _version_cache.pop(name)
    if cache is not None:
        cache.clear()
    _local_versions.pop(name, None)


def get_setting(key, default=None):
    if default is None:
        default = SETTINGS_DEFAULTS.get(key, "")
    sync_local_cache("settings", _settings_cache)
    cached = _settings_cache.get(key)
    if cached is not None:
        return cached
    value = default
    if "site_settings" in db.tables:
        row = db["site_settings"].find_one(key=key)
        if row is not None and row.get("value") is not None:
            value = str(row["value"])
    _settings_cache.set(key, value)
    return value


def get_int_setting(key, default):
    try:
        return int(get_setting(key, str(default)))
    except (TypeError, ValueError):
        return default


def set_setting(key, value):
    table = db["site_settings"]
    stamp = now_iso()
    with db:
        if table.find_one(key=key) is None:
            table.insert({"uid": f"setting_{key}", "key": key, "value": str(value), "updated_at": stamp})
        else:
            table.update({"key": key, "value": str(value), "updated_at": stamp}, ["key"])
    bump_cache_version("settings", _settings_cache)


def all_settings():
    return {key: get_setting(key, default) for key, default in SETTINGS_DEFAULTS.items()}