bindery/bindery/config.py

"""Configuration. Every setting comes from an environment variable."""

import logging
import os
import shutil
from pathlib import Path

logger = logging.getLogger(__name__)


def flag(value: str, default: bool = False) -> bool:
    """A text value as true or false. A value that is neither gives the default."""
    value = value.strip().lower()
    if value in ("true", "yes", "1", "y", "on"):
        return True
    if value in ("false", "no", "0", "n", "off"):
        return False
    return default


def _bool(name: str, default: bool = False) -> bool:
    return flag(os.getenv(name, ""), default)


def _list(name: str, default: str = "") -> list[str]:
    return [v.strip() for v in os.getenv(name, default).split(",") if v.strip()]


# A relative path is relative to the working folder. Paths are made absolute at once, because Flask's send_file
# reads a relative path from the package folder.
def _path(name: str, default: str) -> Path:
    return Path(os.getenv(name, default)).absolute()


def _optional_path(name: str) -> Path | None:
    value = os.getenv(name, "").strip()
    return Path(value).absolute() if value else None


# A bad value stops the start with one clear line, not with a traceback.
def _number(name: str, default: str) -> float:
    value = os.getenv(name, default).strip()
    try:
        return float(value)
    except ValueError:
        raise SystemExit(f"{name} must be a number, not {value!r}") from None


def _choice(name: str, default: str, choices: tuple[str, ...]) -> str:
    value = os.getenv(name, default).strip().upper()
    if value not in choices:
        raise SystemExit(f"{name} must be one of {', '.join(choices)}, not {value!r}")
    return value


def _base_path(value: str) -> str:
    path = value.strip().strip("/")
    return f"/{path}" if path else ""


PROJECT_ROOT = Path(__file__).resolve().parent.parent

CONFIG_DIR = _path("CONFIG_DIR", "/config")
INGEST_DIR = _optional_path("INGEST_DIR")
TMP_DIR = _path("TMP_DIR", "/tmp/bindery")
LOG_LEVEL = _choice("LOG_LEVEL", "INFO", ("DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL"))
# A path prefix, such as /bindery, for a reverse proxy that forwards the full path.
URL_BASE = _base_path(os.getenv("URL_BASE", ""))

# The CWA account that Bindery uses for the OPDS feed.
CWA_URL = os.getenv("CWA_URL", "").strip()
CWA_USERNAME = os.getenv("CWA_USERNAME", "").strip()
CWA_PASSWORD = os.getenv("CWA_PASSWORD", "")
# Independent, optional read-only databases. HTTP remains the fallback.
CWA_DB_PATH = _optional_path("CWA_DB_PATH")  # Calibre-Web app.db, for logins
CALIBRE_DB_PATH = _optional_path("CALIBRE_DB_PATH")  # calibre metadata.db, for book IDs
# false if the user has no CWA. Bindery then ignores the CWA settings above, and shows nothing about CWA. INGEST_DIR
# still gets each built book, as a plain epub. Only a clear "false" turns CWA off.
CWA_ENABLED = _bool("CWA_ENABLED", True)
CWA_SETTINGS = ("CWA_URL", "CWA_USERNAME", "CWA_PASSWORD", "CWA_DB_PATH", "CALIBRE_DB_PATH")
IGNORED_SETTINGS = [] if CWA_ENABLED else [name for name in CWA_SETTINGS if os.getenv(name, "").strip()]
if not CWA_ENABLED:
    CWA_URL = CWA_USERNAME = CWA_PASSWORD = ""
    CWA_DB_PATH = CALIBRE_DB_PATH = None

UPDATE_INTERVAL_HOURS = _number("UPDATE_INTERVAL_HOURS", "24")
DEFAULT_LOCKED_FIELDS = _list("DEFAULT_LOCKED_FIELDS", "title")

# Logins: none, local, cwa or proxy. An API key works in every mode.
AUTH_METHOD = os.getenv("AUTH_METHOD", "none").strip().lower()
LOCAL_USERNAME = os.getenv("BINDERY_USERNAME", "").strip()
LOCAL_PASSWORD_HASH = os.getenv("BINDERY_PASSWORD_HASH", "").strip()
CWA_ALLOWED_USERS = _list("CWA_ALLOWED_USERS")
# The users of the cwa and proxy modes that can change the global settings. Without a list, each user can.
ADMIN_USERS = _list("BINDERY_ADMIN_USERS")
PROXY_AUTH_USER_HEADER = os.getenv("PROXY_AUTH_USER_HEADER", "X-Remote-User").strip()
PROXY_AUTH_LOGOUT_URL = os.getenv("PROXY_AUTH_LOGOUT_URL", "").strip()
# The addresses and networks that can send the user header. The default is each loopback and private address, so
# a request that comes straight from the internet cannot send it.
PROXY_AUTH_TRUSTED_IPS = _list(
    "PROXY_AUTH_TRUSTED_IPS", "127.0.0.0/8, ::1, 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, fc00::/7, fe80::/10"
)
API_KEY = os.getenv("BINDERY_API_KEY", "").strip()
# The host names that Bindery answers to. A leading dot also allows the subdomains, and * allows every name.
# Without a list, the "none" login mode answers only to addresses and local names. The other modes answer to all.
ALLOWED_HOSTS = [h.lower() for h in _list("ALLOWED_HOSTS")]
SESSION_COOKIE_SECURE = _bool("SESSION_COOKIE_SECURE")
# Take the client address from the last entry of X-Forwarded-For, which a reverse proxy adds.
TRUST_PROXY = _bool("TRUST_PROXY")

# Tests turn off the job threads.
START_THREADS = _bool("BINDERY_START_THREADS", True)

SITE_DELAY = 5  # seconds between two jobs that go to a story site
JOB_LIST_MAX_HOURS = 24 * 30  # the highest allowed value of a "jobs from the last N hours" setting
JOB_LIST_MAX_COUNT = 500  # the highest allowed value of a "to a maximum of N jobs" setting
JOB_HISTORY = JOB_LIST_MAX_HOURS * 60 * 60  # seconds; finished jobs stay this long, for the settings above

DB_PATH = CONFIG_DIR / "bindery.db"
UPLOAD_DIR = CONFIG_DIR / "uploads"  # uploaded epubs wait here for their job, also over a restart
SECRET_KEY_FILE = CONFIG_DIR / ".flask_secret"
PERSONAL_INI = CONFIG_DIR / "personal.ini"
DEFAULT_PERSONAL_INI = PROJECT_ROOT / "data" / "personal.ini"
BACKUP_DIR = CONFIG_DIR / "backups"
BACKUP_COUNT = 7  # daily backups to keep


def prepare() -> None:
    """Make the folders, and give the user a personal.ini to edit on first start."""
    for directory in (CONFIG_DIR, UPLOAD_DIR, TMP_DIR):
        directory.mkdir(parents=True, exist_ok=True)
    # The ingest folder belongs to CWA. A folder that Bindery makes hides a missing volume mount, and CWA
    # never sees its files.
    if INGEST_DIR and not INGEST_DIR.is_dir():
        logger.error(
            f"The ingest folder {INGEST_DIR} does not exist. Check INGEST_DIR and the volume mount. "
            "Uploads fail until the folder exists."
        )
    if not PERSONAL_INI.exists():
        shutil.copy(DEFAULT_PERSONAL_INI, PERSONAL_INI)
        logger.info(f"Created the default FanFicFare configuration at {PERSONAL_INI}")
    if not CWA_ENABLED:
        if IGNORED_SETTINGS:
            logger.info(f"CWA_ENABLED is false. Bindery ignores {', '.join(IGNORED_SETTINGS)}.")
        return
    if CWA_PASSWORD and not CWA_USERNAME:
        logger.warning("CWA_PASSWORD is set, but CWA_USERNAME is not. Bindery sends no login to CWA.")
    missing = _missing_cwa()
    for warning in missing:
        logger.warning(warning)
    if missing:
        logger.warning("If you do not use CWA, set CWA_ENABLED=false. Bindery then shows no messages about CWA.")


def _missing_cwa() -> list[str]:
    """What Bindery cannot do with CWA, because a setting is not set."""
    missing = []
    if INGEST_DIR is None:
        missing.append("INGEST_DIR is not set. Bindery sends no book to CWA.")
    if not (CWA_URL or CALIBRE_DB_PATH):
        effect = ", so each update adds a new book to CWA." if INGEST_DIR else "."
        missing.append(
            "CWA_URL and CALIBRE_DB_PATH are not set. Bindery cannot find the library book of a story" + effect
        )
    elif not CWA_URL:
        missing.append("CWA_URL is not set. Bindery cannot search the CWA library, or import books from it.")
    return missing