Convert beancount journal to a JSON format

b2j.py

#!/usr/bin/env python3
from beancount import loader
from beancount.core.amount import Amount
from beancount.core.number import Decimal
from datetime import date
import json
import sys

def json_serial(obj):
    if isinstance(obj, date):
        serial = obj.isoformat()
        return serial
    if isinstance(obj, Decimal):
        return float(obj)
    if isinstance(obj, Amount):
        return {obj.currency: float(obj.number)}
    raise TypeError("Type not serializable %s: %s" % (type(obj), obj))

def convert_entry(e):
    name = type(e).__name__
    e = e._asdict()
    e['_type'] = name
    if 'postings' in e:
        e['postings'] = [convert_entry(p) for p in e['postings']]
    if e.get('meta', None) is not None and 'filename' in e['meta']:
        del e['meta']['filename']
    return e

if __name__ == '__main__':
    entries, errors, options = loader.load_file(sys.argv[1])
    result = json.dumps([convert_entry(e) for e in entries], default=json_serial)
    print(result)

Adjustment for tags (Type not serializable <class 'frozenset'>: frozenset({'test-tag'})):

def json_serial(obj):
    print(obj)
    if isinstance(obj, date):
        serial = obj.isoformat()
        return serial
    if isinstance(obj, Decimal):
        return float(obj)
    if isinstance(obj, Amount):
        return {obj.currency: float(obj.number)}
    if isinstance(obj, frozenset): # <--
        return list(obj)
    raise TypeError("Type not serializable %s: %s" % (type(obj), obj))