Pynomina

OsProject

OsProject
id	pynomina
state	active
owner	WolfgangFahl
title	pynomina
url	https://github.com/WolfgangFahl/pynomina
version	0.0.5
description	personal finance tool
date	2024-10-10
since	2024-10-06
until

Demo

https://nomina.bitplan.com

Introduction

pynomina is a personal finance tool designed to provide a flexible and enduring solution for managing financial records from diverse personal accounting tool sources. It aims to address the challenges of data conversion between different accounting software and ensure long-term readability of financial data. There is only limited support for the actual accounting tasks - this can be done much better by existing commercial and open source solutions. pynomina aims to give you the long-term freedom of choice between tools.

Motivation

In the past decades the author used different personal accounting tools:

• Quicken
• Microsoft Money
• Lexware Finanzmanager
• BankingZV

The pain the conversion between those tools created was finally big enough to do something about it.

Goals

• use a computer and human-readable ledger format that is ready to survive decades
• convert from and to the formats of the tool of choice
• allow for simple sanity checks and reports
• allow for systematic tidy up
• allow for integration into a larger organizational knowledge graph

Hub & Spoke Conversion

The pyNomina tool follows a Hub and Spoke model for conversion between different personal accounting file formats. The Ledger Book (YAML/JSON) format acts as the hub, with each supported format serving as a spoke. This setup simplifies conversions by allowing data to be transformed from any spoke to the hub and then to any other spoke format.

Supported Formats

Format	Type	Description	Wikidata Entry
Ledger Book YAML/JSON	Hub	Main format of pyNomina for converting between formats.	Ledger Book
Beancount	Spoke	A plaintext accounting format.	Beancount
GnuCash XML	Spoke	An XML-based format used by GnuCash.	GnuCash
Microsoft Money	Spoke	Zip File exported with mny_export script using mdb-tools	Microsoft Money
Finanzmanager Deluxe (QIF)	Spoke	A variant of QIF used by Finanzmanager Deluxe.	Finanzmanager Deluxe
Quicken Interchange Format	Spoke	Quicken Interchange Format (QIF)	Quicken
pyNomina Banking ZV YAML	Spoke	A format for exporting banking data in YAML or JSON.	Banking ZV

Installation

pip install pynomina
# alternatively if your pip is not a python3 pip
pip3 install pynomina 
# local install from source directory of pynomina 
pip install .

upgrade

pip install pynomina  -U
# alternatively if your pip is not a python3 pip
pip3 install pynomina -U

tickets

1. Issue 2 - setup open checkos compatible opensource project✓

Testing

The testcases are python unittest modules see https://github.com/WolfgangFahl/pynomina/tree/main/tests. These tests are run as part of the continuous integration github actions To run the tests manually there is a "test" script in the scripts directory:

scripts/test 
Starting test test_read_bzv, debug=True ...
# Accounts: 3
# Transactions: 2
Date Range: 2024-10-06 to 2024-10-06
# Categories: 1
# Currencies: EUR: 2
Other Details:
  name: expenses2024
  owner: John Doe
test test_read_bzv, debug=True took   0.0 s
.Starting test test_conversions, debug=True ...
Converting Ledger Book None to GC-XML

...
Ran 17 tests in 4.518s

OK

see also https://github.com/WolfgangFahl/pynomina/issues/3

Ledger Book

The pynomina Ledger Book model consists of four main classes:

• Book
• Account
• Transaction
• Split

These are the necessary classes which work together to represent a comprehensive financial ledger records.

Class Structure

Book

The Book class represents the main container for all financial data. It includes:

• Basic information: name, owner, creation date, and source URL
• Collections of accounts and transactions
• Methods for managing accounts and transactions, including:
  • get_stats(): Retrieves statistics about the book
  • filter(): Filters transactions by date range
  • create_account(): Creates a new account
  • add_account(): Adds an account to the book
  • lookup_account(): Finds an account by ID

Account

The Account class represents a hierarchy of individual financial accounts within the ledger. It includes:

• account_id: Unique identifier for the account
• name: Human-readable account name
• account_type: Type of account (e.g., EXPENSE, INCOME)
• description: Optional account description
• currency: Account currency (default: EUR)
• parent_account_id: Optional parent account for hierarchical structure

Transaction

The Transaction class represents individual financial transactions. It includes:

• isodate: Date of the transaction in International Standards Organization date format yyyy-mm-dd
• description: Description of the transaction
• splits: List of Split objects representing the movement of money
• payee: Optional payee information
• memo: Optional additional notes
• total_amount(): Method to calculate the total transaction amount

Split

The Split class represents the individual components of a transaction, showing how money moves between accounts. It includes:

• amount: The amount of money involved in the split
• account_id: The account associated with this part of the transaction
• memo: Optional notes for this split
• reconciled: Boolean indicating if the split has been reconciled

Example Data

Here's an example of how the ledger model is used in practice:

Yaml Format

owner: Wolfgang Fahl
url: https://github.com/WolfgangFahl/pynomina/blob/main/nomina_examples/expenses2024.yaml
since: 2024-10-06
accounts:
  Expenses:
    account_id: Expenses
    name: Expenses
    account_type: EXPENSE
    description: 'General Expenses'
    currency: EUR
  Expenses:Food:
    account_id: Expenses:Food
    name: Dining
    account_type: EXPENSE
    description: 'Expenses for Food'
    currency: EUR
    parent_account_id: Expenses
  Cash in wallet:
    account_id: Wallet
    name: Cash in Wallet
    account_type: EXPENSE
    description: ''
    currency: EUR
transactions:
  Bakery2024-10-06_0900_1:
    isodate: '2024-10-06'
    description: Bread
    splits:
      - amount: -3.50
        account_id: Cash in Wallet
      - amount: 3.50
        account_id: Expenses:Dining
        memo: Fresh sourdough bread
  Bakery2024-10-06_0900_2:
    isodate: '2024-10-06'
    description: Buns for Breakfast
    splits:
      - amount: -2.40
        account_id: Cash in Wallet
      - amount: 2.40
        account_id: Expenses:Dining
        memo: 4 whole grain buns

Implementation

The ledger model is implemented in Python, utilizing dataclasses and type hinting for clear and maintainable code. The `@lod_storable` decorator is used to enable easy serialization and deserialization of the data in YAML and/or JSON and other formats. The core idea is that the records should be readily available an tabular "list of dicts (lod)" format.