def _record_transfer_result(db, t_id, status, error=None):
balance = None
with db.get_cursor() as c:
tipper, tippee, amount = c.one("""
UPDATE transfers
SET status = %s
, error = %s
WHERE id = %s
RETURNING tipper, tippee, amount
""", (status, error, t_id))
if status == 'succeeded':
balance = c.one("""
UPDATE participants
SET balance = balance + %(amount)s
WHERE id = %(tippee)s;
UPDATE participants
SET balance = balance - %(amount)s
WHERE id = %(tipper)s
AND balance - %(amount)s >= 0
RETURNING balance;
""", locals())
if balance is None:
raise NegativeBalance
bundles = c.all("""
LOCK TABLE cash_bundles IN EXCLUSIVE MODE;
SELECT b.*
FROM cash_bundles b
JOIN exchanges e ON e.id = b.origin
WHERE b.owner = %s
ORDER BY e.participant = %s DESC, b.ts
""", (tipper, tippee))
x = amount
for b in bundles:
if x >= b.amount:
c.run("""
UPDATE cash_bundles
SET owner = %s
WHERE id = %s
""", (tippee, b.id))
x -= b.amount
if x == 0:
break
else:
c.run("""
UPDATE cash_bundles
SET amount = (amount - %s)
WHERE id = %s;
INSERT INTO cash_bundles
(owner, origin, amount, ts)
VALUES (%s, %s, %s, %s);
""", (x, b.id, tippee, b.origin, x, b.ts))
break
if balance is not None:
merge_cash_bundles(db, tippee)
return balance
raise TransferError(error)
def record_transfer_result(db, t_id, tr, _raise=False):
error = repr_error(tr)
status = tr.Status.lower()
assert (not error) ^ (status == 'failed')
r = _record_transfer_result(db, t_id, status, error)
if _raise and status == 'failed':
raise TransferError(error)
return r
def execute_transfer(db, t_id, tr):
try:
tr.save()
except APIError as e:
error = repr_exception(e)
_record_transfer_result(db, t_id, 'failed', error)
from liberapay.website import website
website.tell_sentry(e, {})
raise TransferError(error)
return record_transfer_result(db, t_id, tr, _raise=True)