# Part of accounting-api project:
# https://gitorious.org/conservancy/accounting-api
# License: AGPLv3-or-later
import sys
import subprocess
import logging
import time
import re
from datetime import datetime
from xml.etree import ElementTree
from contextlib import contextmanager
from accounting.exceptions import AccountingException
from accounting.models import Account, Transaction, Posting, Amount
from accounting.storage import Storage, TransactionNotFound
_log = logging.getLogger(__name__)
class Ledger(Storage):
def __init__(self, app=None, ledger_file=None, ledger_bin=None):
if app:
ledger_file = app.config['LEDGER_FILE']
if ledger_file is None:
raise ValueError('ledger_file cannot be None')
self.ledger_bin = ledger_bin or 'ledger'
self.ledger_file = ledger_file
_log.info('ledger file: %s', ledger_file)
self.locked = False
self.ledger_process = None
@contextmanager
def locked_process(self):
r'''
Context manager that checks that the ledger process is not already
locked, then "locks" the process and yields the process handle and
unlocks the process when execution is returned.
Since this decorated as a :func:`contextlib.contextmanager` the
recommended use is with the ``with``-statement.
.. code-block:: python
with self.locked_process() as p:
p.stdin.write(b'bal\n')
output = self.read_until_prompt(p)
'''
if self.locked:
raise RuntimeError('The process has already been locked,'
' something\'s out of order.')
# XXX: This code has no purpose in a single-threaded process
timeout = 5 # Seconds
for i in range(1, timeout + 2):
if i > timeout:
raise RuntimeError('Ledger process is already locked')
if not self.locked:
break
else:
_log.info('Waiting for one second... %d/%d', i, timeout)
time.sleep(1)
process = self.get_process()
self.locked = True
_log.debug('Lock enabled')
yield process
self.locked = False
_log.debug('Lock disabled')
def assemble_arguments(self):
'''
Returns a list of arguments suitable for :class:`subprocess.Popen`
based on :attr:`self.ledger_bin` and :attr:`self.ledger_file`.
'''
return [
self.ledger_bin,
'-f',
self.ledger_file,
]
def init_process(self):
'''
Creates a new (presumably) ledger subprocess based on the args from
:meth:`Ledger.assemble_arguments()` and then runs
:meth:`Ledger.read_until_prompt()` once (which should return the banner
text) and discards the output.
'''
_log.debug('Starting ledger process...')
self.ledger_process = subprocess.Popen(
self.assemble_arguments(),
stdout=subprocess.PIPE,
stdin=subprocess.PIPE,
stderr=subprocess.PIPE)
# Swallow the banner
with self.locked_process() as p:
self.read_until_prompt(p)
return self.ledger_process
def get_process(self):
'''
Returns :attr:`self.ledger_process` if it evaluates to ``True``. If
:attr:`self.ledger_process` is not set the result of
:meth:`self.init_process() <Ledger.init_process>` is returned.
'''
return self.ledger_process or self.init_process()
def read_until_prompt(self, process):
r'''
Reads from the subprocess instance :data:`process` until it finds a
combination of ``\n]\x20`` (the prompt), then returns the output
without the prompt.
'''
output = b''
while True:
line = process.stdout.read(1) # XXX: This is a hack
output += line
if b'\n] ' in output:
_log.debug('Found prompt!')
break
output = output[:-3] # Cut away the prompt
_log.debug('output: %s', output)
return output
def send_command(self, command):
output = None
with self.locked_process() as p:
if isinstance(command, str):
command = command.encode('utf8')
p.stdin.write(command + b'\n')
p.stdin.flush()
output = self.read_until_prompt(p)
self.ledger_process.send_signal(subprocess.signal.SIGTERM)
_log.debug('Waiting for ledger to shut down')
self.ledger_process.wait()
self.ledger_process = None
return output
def add_transaction(self, transaction):
'''
Writes a transaction to the ledger file by opening it in 'ab' mode and
writing a ledger transaction based on the
:class:`~accounting.models.Transaction` instance in
:data:`transaction`.
'''
if transaction.id is None:
_log.debug('No ID found. Generating an ID.')
transaction.generate_id()
transaction.metadata.update({'Id': transaction.id})
transaction_template = ('\n{date} {t.payee}\n'
'{metadata}'
'{postings}')
metadata_template = ' ;{0}: {1}\n'
# TODO: Generate metadata for postings
posting_template = (' {account} {p.amount.symbol}'
' {p.amount.amount}\n')
output = b''
# XXX: Even I hardly understands what this does, however I indent it it
# stays unreadable.
output += transaction_template.format(
date=transaction.date.strftime('%Y-%m-%d'),
t=transaction,
metadata=''.join([
metadata_template.format(k, v)
for k, v in transaction.metadata.items()]),
postings=''.join([posting_template.format(
p=p,
account=p.account + ' ' * (
80 - (len(p.account) + len(p.amount.symbol) +
len(str(p.amount.amount)) + 1 + 2)
)) for p in transaction.postings
])
).encode('utf8')
with open(self.ledger_file, 'ab') as f:
f.write(output)
_log.debug('written to file: %s', output)
return transaction.id
def bal(self):
output = self.send_command('xml')
if output is None:
raise RuntimeError('bal call returned no output')
accounts = []
xml = ElementTree.fromstring(output.decode('utf8'))
accounts = self._recurse_accounts(xml.find('./accounts'))
return accounts
def _recurse_accounts(self, root):
accounts = []
for account in root.findall('./account'):
name = account.find('./fullname').text
amounts = []
# Try to find an account total value, then try to find the account
# balance
account_amounts = account.findall(
'./account-total/balance/amount') or \
account.findall('./account-amount/amount') or \
account.findall('./account-total/amount')
if account_amounts:
for amount in account_amounts:
quantity = amount.find('./quantity').text
symbol = amount.find('./commodity/symbol').text
amounts.append(Amount(amount=quantity, symbol=symbol))
else:
_log.warning('Account %s does not have any amounts', name)
accounts.append(Account(name=name,
amounts=amounts,
accounts=self._recurse_accounts(account)))
return accounts
def get_transactions(self):
return self.reg()
def get_transaction(self, transaction_id):
transactions = self.get_transactions()
for transaction in transactions:
if transaction.id == transaction_id:
return transaction
raise TransactionNotFound('No transaction with id %s found',
transaction_id)
def reg(self):
output = self.send_command('xml')
if output is None:
raise RuntimeError('reg call returned no output')
entries = []
reg_xml = ElementTree.fromstring(output.decode('utf8'))
for transaction in reg_xml.findall('./transactions/transaction'):
date = datetime.strptime(transaction.find('./date').text,
'%Y/%m/%d')
payee = transaction.find('./payee').text
postings = []
for posting in transaction.findall('./postings/posting'):
account = posting.find('./account/name').text
amount = posting.find('./post-amount/amount/quantity').text
symbol = posting.find(
'./post-amount/amount/commodity/symbol').text
# Get the posting metadata
metadata = {}
values = posting.findall('./metadata/value')
if values:
for value in values:
key = value.get('key')
value = value.find('./string').text
_log.debug('metadata: %s: %s', key, value)
metadata.update({key: value})
postings.append(
Posting(account=account,
metadata=metadata,
amount=Amount(amount=amount, symbol=symbol)))
# Get the transaction metadata
metadata = {}
values = transaction.findall('./metadata/value')
if values:
for value in values:
key = value.get('key')
value = value.find('./string').text
_log.debug('metadata: %s: %s', key, value)
metadata.update({key: value})
# Add a Transaction instance to the list
id = metadata.pop('Id')
entries.append(
Transaction(id=id, date=date, payee=payee, postings=postings,
metadata=metadata))
return entries
def delete_transaction(self, transaction_id):
'''
Delete a transaction from the ledger file.
This method opens the ledger file, loads all lines into memory and
looks for the transaction_id, then looks for the bounds of that
transaction in the ledger file, removes all lines within the bounds of
the transaction and removes them, then writes the lines back to the
ledger file.
Exceptions:
- RuntimeError: If all boundaries to the transaction are not found
- TransactionNotFound: If no such transaction_id can be found in
:data:`self.ledger_file`
'''
f = open(self.ledger_file, 'r')
lines = [i for i in f]
# A mapping of line meanings and their line numbers as found by the
# following logic
semantic_lines = dict(
id_location=None,
transaction_start=None,
next_transaction_or_eof=None
)
for i, line in enumerate(lines):
if transaction_id in line:
semantic_lines['id_location'] = i
break
if not semantic_lines['id_location']:
raise TransactionNotFound(
'No transaction with ID "{0}" found'.format(transaction_id))
transaction_start_pattern = re.compile(r'^\S')
cursor = semantic_lines['id_location'] - 1
# Find the first line of the transaction
while True:
if transaction_start_pattern.match(lines[cursor]):
semantic_lines['transaction_start'] = cursor
break
cursor -= 1
cursor = semantic_lines['id_location'] + 1
# Find the last line of the transaction
while True:
try:
if transaction_start_pattern.match(lines[cursor]):
semantic_lines['next_transaction_or_eof'] = cursor
break
except IndexError:
# Set next_line_without_starting_space_or_end_of_file to
# the cursor. The cursor will be an index not included in the
# list of lines
semantic_lines['next_transaction_or_eof'] = cursor
break
cursor += 1
if not all(map(lambda v: v is not None, semantic_lines.values())):
raise RuntimeError('Could not find all the values necessary for'
' safe deletion of a transaction.')
del_start = semantic_lines['transaction_start']
if len(lines) == semantic_lines['next_transaction_or_eof']:
_log.debug('There are no transactions below the transaction being'
' deleted. The line before the first line of the'
' transaction will be deleted.')
# Delete the preceding line to make the file
del_start -= 1
del lines[del_start:semantic_lines['next_transaction_or_eof']]
with open(self.ledger_file, 'w') as f:
for line in lines:
f.write(line)
def update_transaction(self, transaction):
'''
Update a transaction in the ledger file.
Takes a :class:`~accounting.models.Transaction` object and removes
the old transaction using :data:`transaction.id` from the passed
:class:`~accounting.models.Transaction` instance and adds
:data:`transaction` to the database.
'''
if not transaction.id:
return AccountingException(('The transaction {0} has no'
' id attribute').format(transaction))
old_transaction = self.get_transaction(transaction.id)
self.delete_transaction(transaction.id)
self.add_transaction(transaction)
_log.debug('Updated transaction from: %s to: %s', old_transaction,
transaction)
def main(argv=None):
import argparse
if argv is None:
argv = sys.argv
parser = argparse.ArgumentParser()
parser.add_argument('-v', '--verbosity',
default='INFO',
help=('Filter logging output. Possible values:' +
' CRITICAL, ERROR, WARNING, INFO, DEBUG'))
args = parser.parse_args(argv[1:])
logging.basicConfig(level=getattr(logging, args.verbosity, 'INFO'))
ledger = Ledger(ledger_file='non-profit-test-data.ledger')
print(ledger.bal())
print(ledger.reg())
if __name__ == '__main__':
sys.exit(main())