From 55b15473e1e625908a57032db8e446777b4aebf0 Mon Sep 17 00:00:00 2001
From: Jean-Paul Calderone <exarkun@twistedmatrix.com>
Date: Mon, 18 Nov 2019 11:04:40 -0500
Subject: [PATCH] Redeeming and unpaid states
---
src/_zkapauthorizer/controller.py | 78 ++++++++++++++++---
src/_zkapauthorizer/model.py | 67 ++++++++++------
.../tests/test_client_resource.py | 10 ++-
3 files changed, 117 insertions(+), 38 deletions(-)
diff --git a/src/_zkapauthorizer/controller.py b/src/_zkapauthorizer/controller.py
index ba49e35..fb3bd82 100644
--- a/src/_zkapauthorizer/controller.py
+++ b/src/_zkapauthorizer/controller.py
@@ -17,6 +17,13 @@ This module implements controllers (in the MVC sense) for the web interface
for the client side of the storage plugin.
"""
+from sys import (
+ exc_info,
+)
+from operator import (
+ setitem,
+ delitem,
+)
from functools import (
partial,
)
@@ -60,8 +67,9 @@ from .model import (
UnblindedToken,
Voucher,
Pass,
- Pending,
+ Pending as model_Pending,
Unpaid as model_Unpaid,
+ Redeeming as model_Redeeming,
)
@@ -434,11 +442,13 @@ class PaymentController(object):
The ``PaymentController`` coordinates the process of turning a voucher
into a collection of ZKAPs:
- 1. A voucher to be consumed is handed to the controller.
- Once a voucher is handed over to the controller the controller takes all responsibility for it.
+ 1. A voucher to be consumed is handed to the controller. Once a voucher
+ is handed over to the controller the controller takes all
+ responsibility for it.
- 2. The controller tells the data store to remember the voucher.
- The data store provides durability for the voucher which represents an investment (ie, a purchase) on the part of the client.
+ 2. The controller tells the data store to remember the voucher. The
+ data store provides durability for the voucher which represents an
+ investment (ie, a purchase) on the part of the client.
3. The controller hands the voucher and some random tokens to a redeemer.
In the future, this step will need to be retried in the case of failures.
@@ -448,6 +458,10 @@ class PaymentController(object):
the voucher. The data store marks the voucher as redeemed and stores
the unblinded tokens for use by the storage client.
+ :ivar dict[voucher, datetime] _active: A mapping from voucher identifiers
+ which currently have redemption attempts in progress to timestamps
+ when the attempt began.
+
:ivar dict[voucher, datetime] _unpaid: A mapping from voucher identifiers
which have recently failed a redemption attempt due to an unpaid
response from the redemption server to timestamps when the failure was
@@ -459,6 +473,7 @@ class PaymentController(object):
redeemer = attr.ib()
_unpaid = attr.ib(default=attr.Factory(dict))
+ _active = attr.ib(default=attr.Factory(dict))
def redeem(self, voucher, num_tokens=100):
"""
@@ -484,7 +499,11 @@ class PaymentController(object):
# Ask the redeemer to do the real task of redemption.
self._log.info("Redeeming random tokens for a voucher ({voucher}).", voucher=voucher)
- d = self.redeemer.redeem(Voucher(voucher), tokens)
+ d = bracket(
+ lambda: setitem(self._active, voucher, self.store.now()),
+ lambda: delitem(self._active, voucher),
+ lambda: self.redeemer.redeem(Voucher(voucher), tokens),
+ )
d.addCallbacks(
partial(self._redeemSuccess, voucher),
partial(self._redeemFailure, voucher),
@@ -533,11 +552,17 @@ class PaymentController(object):
example, if a redemption attempt is current in progress, this is
incorporated.
"""
- if isinstance(voucher.state, Pending) and voucher.number in self._unpaid:
- return attr.evolve(
- voucher,
- state=model_Unpaid(finished=self._unpaid[voucher.number]),
- )
+ if isinstance(voucher.state, model_Pending):
+ if voucher.number in self._active:
+ return attr.evolve(
+ voucher,
+ state=model_Redeeming(started=self._active[voucher.number]),
+ )
+ if voucher.number in self._unpaid:
+ return attr.evolve(
+ voucher,
+ state=model_Unpaid(finished=self._unpaid[voucher.number]),
+ )
return voucher
@@ -558,3 +583,34 @@ _REDEEMERS = {
u"unpaid": UnpaidRedeemer.make,
u"ristretto": RistrettoRedeemer.make,
}
+
+
+@inlineCallbacks
+def bracket(first, last, between):
+ """
+ Invoke an action between two other actions.
+
+ :param first: A no-argument function that may return a Deferred. It is
+ called first.
+
+ :param last: A no-argument function that may return a Deferred. It is
+ called last.
+
+ :param between: A no-argument function that may return a Deferred. It is
+ called after ``first`` is done and completes before ``last`` is called.
+
+ :return Deferred: A ``Deferred`` which fires with the result of
+ ``between``.
+ """
+ yield first()
+ try:
+ result = yield between()
+ except GeneratorExit:
+ raise
+ except:
+ info = exc_info()
+ yield last()
+ raise info
+ else:
+ yield last()
+ returnValue(result)
diff --git a/src/_zkapauthorizer/model.py b/src/_zkapauthorizer/model.py
index 95780c8..4337dec 100644
--- a/src/_zkapauthorizer/model.py
+++ b/src/_zkapauthorizer/model.py
@@ -466,7 +466,26 @@ class RandomToken(object):
@attr.s(frozen=True)
class Pending(object):
- pass
+ def to_json_v1(self):
+ return {
+ u"name": u"pending",
+ }
+
+
+@attr.s(frozen=True)
+class Redeeming(object):
+ """
+ This is a non-persistent state in which a voucher exists when the database
+ state is **pending** but for which there is a redemption operation in
+ progress.
+ """
+ started = attr.ib(validator=attr.validators.instance_of(datetime))
+
+ def to_json_v1(self):
+ return {
+ u"name": u"redeeming",
+ u"started": self.started.isoformat(),
+ }
@attr.s(frozen=True)
@@ -474,11 +493,24 @@ class Redeemed(object):
finished = attr.ib(validator=attr.validators.instance_of(datetime))
token_count = attr.ib(validator=attr.validators.instance_of((int, long)))
+ def to_json_v1(self):
+ return {
+ u"name": u"redeemed",
+ u"finished": self.finished.isoformat(),
+ u"token-count": self.token_count,
+ }
+
@attr.s(frozen=True)
class DoubleSpend(object):
finished = attr.ib(validator=attr.validators.instance_of(datetime))
+ def to_json_v1(self):
+ return {
+ u"name": u"double-spend",
+ u"finished": self.finished.isoformat(),
+ }
+
@attr.s(frozen=True)
class Unpaid(object):
@@ -489,6 +521,12 @@ class Unpaid(object):
"""
finished = attr.ib(validator=attr.validators.instance_of(datetime))
+ def to_json_v1(self):
+ return {
+ u"name": u"unpaid",
+ u"finished": self.finished.isoformat(),
+ }
+
@attr.s
class Voucher(object):
@@ -554,6 +592,10 @@ class Voucher(object):
state_name = state_json[u"name"]
if state_name == u"pending":
state = Pending()
+ elif state_name == u"redeeming":
+ state = Redeeming(
+ started=parse_datetime(state_json[u"started"]),
+ )
elif state_name == u"double-spend":
state = DoubleSpend(
finished=parse_datetime(state_json[u"finished"]),
@@ -586,28 +628,7 @@ class Voucher(object):
def to_json_v1(self):
- if isinstance(self.state, Pending):
- state = {
- u"name": u"pending",
- }
- elif isinstance(self.state, DoubleSpend):
- state = {
- u"name": u"double-spend",
- u"finished": self.state.finished.isoformat(),
- }
- elif isinstance(self.state, Redeemed):
- state = {
- u"name": u"redeemed",
- u"finished": self.state.finished.isoformat(),
- u"token-count": self.state.token_count,
- }
- elif isinstance(self.state, Unpaid):
- state = {
- u"name": u"unpaid",
- u"finished": self.state.finished.isoformat(),
- }
- else:
- raise ValueError("Unrecognized state {!r}".format(self.state.__class__))
+ state = self.state.to_json_v1()
return {
u"number": self.number,
u"created": None if self.created is None else self.created.isoformat(),
diff --git a/src/_zkapauthorizer/tests/test_client_resource.py b/src/_zkapauthorizer/tests/test_client_resource.py
index cfc9a8c..7af34c1 100644
--- a/src/_zkapauthorizer/tests/test_client_resource.py
+++ b/src/_zkapauthorizer/tests/test_client_resource.py
@@ -112,7 +112,7 @@ from treq.testing import (
from ..model import (
Voucher,
- Pending,
+ Redeeming,
Redeemed,
DoubleSpend,
Unpaid,
@@ -599,11 +599,11 @@ class VoucherTests(TestCase):
)
@given(tahoe_configs(client_nonredeemer_configurations()), datetimes(), vouchers())
- def test_get_known_voucher_pending(self, get_config, now, voucher):
+ def test_get_known_voucher_redeeming(self, get_config, now, voucher):
"""
When a voucher is first ``PUT`` and then later a ``GET`` is issued for the
same voucher then the response code is **OK** and details, including
- those relevant to a voucher which is still pending redemption, about
+ those relevant to a voucher which is actively being redeemed, about
the voucher are included in a json-encoded response body.
"""
return self._test_get_known_voucher(
@@ -613,7 +613,9 @@ class VoucherTests(TestCase):
MatchesStructure(
number=Equals(voucher),
created=Equals(now),
- state=Equals(Pending()),
+ state=Equals(Redeeming(
+ started=now,
+ )),
),
)
--
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