dump all models when load sqlalchemy

dump.py

import os
import json
import hashlib
import datetime

from database import db
from sqlalchemy import event


def literal_sql(context):
    statement = context.statement
    session = context.session
    try:
        dialect = session.get_bind().dialect
        compiled = statement.compile(dialect=dialect,
                                     compile_kwargs={'literal_binds': True})
        return str(compiled).replace("\n", "")
    except Exception:
        return str(statement).replace("\n", "")


def dump(data, fp):
    def default(o):
        if isinstance(o, (datetime.date, datetime.datetime)):
            return o.isoformat()
    return json.dump(
        data,
        fp,
        sort_keys=True,
        indent=1,
        default=default
    )


@event.listens_for(db.Model, "load", propagate=True)
def _record_loaded_instances(target, context):
    # from sqlalchemy.ext.serializer import loads, dumps
    obj = {c.name: getattr(target, c.name) for c in target.__table__.columns}
    literal = literal_sql(context)
    perm = {}
    if os.path.exists("dump.json"):
        with open("dump.json", "r") as f:
            perm = json.load(f)
    key = hashlib.md5(literal.encode('utf-8')).hexdigest()
    if key not in perm:
        class_path = "%s.%s" % (target.__class__.__module__,
                                target.__class__.__name__)
        perm[key] = {"sql": literal, "obj": obj,
                     "class": class_path}
    with open("dump.json", "w") as f:
        dump(perm, f)
    print(literal)
    print(obj)