OsProject

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.

https://diagrams.bitplan.com/render/png/0xa0be5aae.png

Supported Formats

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

Usage

command line

nomina -h
usage: nomina [-h] [-a] [--apache APACHE] [-c] [-d]
              [--debugServer DEBUGSERVER] [--debugPort DEBUGPORT]
              [--debugRemotePath DEBUGREMOTEPATH]
              [--debugLocalPath DEBUGLOCALPATH] [-l] [-i INPUT] [-rol]
              [--host HOST] [--port PORT] [-s] [-V] [-v] [-rp ROOT_PATH]
              [--convert CONVERT] [--format {LB-YAML,GC-XML,BEAN}] [-o OUTPUT]
Personal finance tool
options:
  -h, --help            show this help message and exit
  -a, --about           show about info [default: False]
  --apache APACHE       create an apache configuration file for the given
                        domain
  -c, --client          start client [default: False]
  -d, --debug           show debug info [default: False]
  --debugServer DEBUGSERVER
                        remote debug Server
  --debugPort DEBUGPORT
                        remote debug Port
  --debugRemotePath DEBUGREMOTEPATH
                        remote debug Server path mapping - remotePath - path
                        on debug server
  --debugLocalPath DEBUGLOCALPATH
                        remote debug Server path mapping - localPath - path on
                        machine where python runs
  -l, --local           run with local file system access [default: False]
  -i INPUT, --input INPUT
                        input file
  -rol, --render_on_load
                        render on load [default: False]
  --host HOST           the host to serve / listen from [default: localhost]
  --port PORT           the port to serve from [default: 9849]
  -s, --serve           start webserver [default: False]
  -V, --version         show program's version number and exit
  -v, --verbose         show verbose output [default: False]
  -rp ROOT_PATH, --root_path ROOT_PATH
                        path to nomina files [default:
                        /Users/wf/Library/Python/3.12/lib/python/site-
                        packages/nomina_examples]
  --convert CONVERT     Convert the specified file to the desired format
  --format {LB-YAML,GC-XML,BEAN}
                        Output format for conversion [default: LB-YAML]
  -o OUTPUT, --output OUTPUT
                        Output file

command line conversion

There is a script test_cmdline that tries out some combinations of input and output file formats. see also Issue 7:command line conversion support

scripts/test_cmdline 
nomina_examples/empty.yaml →  /tmp/nomina/empty_converted.yaml: LB-YAML✅
nomina_examples/empty.yaml →  /tmp/nomina/empty_converted.gnucash: GC-XML✅
nomina_examples/empty.yaml →  /tmp/nomina/empty_converted.beancount: BEAN✅
...

starting as local webapp

nomina -s -l 
NiceGUI ready to go on http://localhost:9849

Tutorials

Quicken

Pynomina/Quicken

GnuCash

Pynomina/GnuCash

Beancount

Pynomina/Beancount

Microsoft Money

Pynomina/MsMoney

tickets

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

https://diagrams.bitplan.com/render/png/0xfec2cab6.png

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.