Sindbad~EG File Manager

#!/opt/alt/python37/bin/python3 -bb
# coding=utf-8
#
# Copyright © Cloud Linux GmbH & Cloud Linux Software, Inc 2010-2020 All Rights Reserved
#
# Licensed under CLOUD LINUX LICENSE AGREEMENT
# http://cloudlinux.com/docs/LICENCE.TXT
#

import os
import contextlib
import sqlite3

from datetime import datetime, timedelta
from sqlalchemy import (
    Column,
    Boolean,
    DateTime,
    Integer,
    String,
    create_engine,
    event, func
)
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.engine.reflection import Inspector
from sqlalchemy.orm import Session

SSA_DB = '/var/lve/ssa.db'
RETENTION_TIME_DAYS = 1

Base = declarative_base()


class RequestResult(Base):
    """
    Describes processed request stored in database file.

    E.g.
    {
        "timestamp": "1650008727",
        "url": "http://mydomain.com/index.php",
        "duration": 162077,
        "hitting_limits": false,
        "throttled_time": 0,
        "io_throttled_time": 0,
        "wordpress": true
    }

    Note: created_at, updated_at is saved in local TZ format
    """
    __tablename__ = 'scrape_result'

    id = Column(Integer, primary_key=True)

    domain = Column(String, index=True, nullable=False)
    path = Column(String, index=True, nullable=False)

    timestamp = Column(Integer, nullable=False)

    duration = Column(Integer, nullable=False)
    is_slow_request = Column(Boolean, nullable=False)
    hitting_limits = Column(Boolean, nullable=False)
    throttled_time = Column(Integer, nullable=False)
    io_throttled_time = Column(Integer, nullable=False)
    wordpress = Column(Boolean, nullable=False)

    created_at = Column(DateTime(timezone=True), server_default=func.now())
    updated_at = Column(DateTime(timezone=True), onupdate=func.now(), server_default=func.now())


def cleanup_old_data(engine):
    """
    Removes outdated records from database, saving disk space.
    """
    n_days_ago = datetime.today() - timedelta(days=RETENTION_TIME_DAYS)
    with session_scope(engine) as session:
        session.query(RequestResult)\
            .filter(RequestResult.created_at < n_days_ago)\
            .delete()


def create_db_if_not_exist(engine):
    if not is_db_present(engine):
        Base.metadata.create_all(engine)


def is_db_present(engine):
    if not os.path.isfile(SSA_DB):
        return False
    database_inspection = Inspector.from_engine(engine)
    tables = [table for table in database_inspection.get_table_names()]
    return len(tables) > 0


def setup_wal_mode(dbapi_con, con_record):
    dbapi_con.execute('PRAGMA journal_mode = WAL')


def _setup_database(readonly):
    connection_string = f'file:{SSA_DB}'
    if readonly:
        connection_string = f'{connection_string}?mode=ro'
    creator = lambda: sqlite3.connect(connection_string, uri=True)
    engine = create_engine(
        'sqlite:////', creator=creator, echo=False,
    )
    event.listen(engine, 'connect', setup_wal_mode)
    create_db_if_not_exist(engine)
    return engine


def setup_database(readonly=False):
    return _setup_database(readonly)


@contextlib.contextmanager
def session_scope(engine) -> Session:
    """
    Provide a transactional scope around a series of operations.
    """
    session = Session(bind=engine)
    try:
        yield session
        session.commit()
    except:
        session.rollback()
        raise
    finally:
        session.close()