Add scheduled task to update rates

issue8804
review347191002

CHANGELOG

@@ -1,3 +1,5 @@
+* Add scheduled task to update rates
+
 Version 5.8.0 - 2020-11-02
 * Bug fixes (see mercurial logs for details)
 * Remove support for Python 3.5

__init__.py

@@ -7,7 +7,11 @@ from trytond.pool import Pool
 def register():
     # Prevent to import backend when importing scripts
     from . import currency
+    from . import ir
     Pool.register(
         currency.Currency,
         currency.CurrencyRate,
+        currency.Cron,
+        currency.Cron_Currency,
+        ir.Cron,
         module='currency', type_='model')

currency.py

@@ -1,22 +1,33 @@
 # This file is part of Tryton.  The COPYRIGHT file at the top level of
 # this repository contains the full copyright notices and license terms.
 import datetime
+import logging
 
 from decimal import Decimal, ROUND_HALF_EVEN, localcontext
 
+from dateutil.relativedelta import relativedelta
+
 from sql import Window
 from sql.functions import NthValue
 
+try:
+    from forex_python.converter import CurrencyRates, RatesNotAvailableError
+    get_rates = CurrencyRates(force_decimal=True).get_rates
+except ImportError:
+    CurrencyRates = get_rates = None
+
 from trytond.i18n import gettext
 from trytond.model import (
     ModelView, ModelSQL, DeactivableMixin, fields, Unique, Check, SymbolMixin)
 from trytond.transaction import Transaction
 from trytond.pool import Pool
 from trytond.rpc import RPC
-from trytond.pyson import Eval
+from trytond.pyson import Eval, If
 
 from .exceptions import RateError
 
+logger = logging.getLogger(__name__)
+
 
 class Currency(SymbolMixin, DeactivableMixin, ModelSQL, ModelView):
     'Currency'
@@ -269,3 +280,169 @@ class CurrencyRate(ModelSQL, ModelView):
 
     def get_rec_name(self, name):
         return str(self.date)
+
+
+class CronFetchError(Exception):
+    pass
+
+
+class Cron(ModelSQL, ModelView):
+    "Currency Cron"
+    __name__ = 'currency.cron'
+
+    source = fields.Selection(
+        [], "Source", required=True,
+        help="The external source for rates.")
+    frequency = fields.Selection([
+            ('daily', "Daily"),
+            ('weekly', "Weekly"),
+            ('monthly', "Monthly"),
+            ], "Frequency", required=True,
+        help="How frequently rates must be updated.")
+    weekday = fields.Many2One(
+        'ir.calendar.day', "Day of Week",
+        states={
+            'required': Eval('frequency') == 'weekly',
+            'invisible': Eval('frequency') != 'weekly',
+            },
+        depends=['frequency'])
+    day = fields.Integer(
+        "Day of Month",
+        domain=[If(Eval('frequency') == 'monthly',
+                [('day', '>=', 1), ('day', '<=', 31)],
+                [('day', '=', None)]),
+            ],
+        states={
+            'required': Eval('frequency') == 'monthly',
+            'invisible': Eval('frequency') != 'monthly',
+            },
+        depends=['frequency'])
+    currency = fields.Many2One(
+        'currency.currency', "Currency", required=True,
+        help="The base currency to fetch rate.")
+    currencies = fields.Many2Many(
+        'currency.cron-currency.currency', 'cron', 'currency', "Currencies",
+        help="The currencies to update the rate.")
+    last_update = fields.Date("Last Update", required=True)
+
+    @classmethod
+    def __setup__(cls):
+        super().__setup__()
+        cls._buttons.update({
+                'run': {},
+                })
+        if CurrencyRates:
+            cls.source.selection.append(('ecb', "European Central Bank"))
+
+    @classmethod
+    def default_frequency(cls):
+        return 'monthly'
+
+    @classmethod
+    def default_day(cls):
+        return 1
+
+    @classmethod
+    def default_last_update(cls):
+        pool = Pool()
+        Date = pool.get('ir.date')
+        return Date.today()
+
+    @classmethod
+    @ModelView.button
+    def run(cls, crons):
+        cls.update(crons)
+
+    @classmethod
+    def update(cls, crons=None):
+        pool = Pool()
+        Rate = pool.get('currency.currency.rate')
+        if crons is None:
+            crons = cls.search([])
+        rates = []
+        for cron in crons:
+            rates.extend(cron._update())
+        Rate.save(rates)
+        cls.save(crons)
+
+    def _update(self):
+        limit = self.limit_update()
+        date = self.next_update()
+        while date <= limit:
+            try:
+                yield from self._rates(date)
+            except CronFetchError:
+                logger.warning("Could not fetch rates temporary")
+                break
+            except Exception:
+                logger.error("Fail to fetch rates", exc_info=True)
+                break
+            self.last_update = date
+            date = self.next_update()
+
+    def next_update(self):
+        return self.last_update + self.delta()
+
+    def limit_update(self):
+        pool = Pool()
+        Date = pool.get('ir.date')
+        return Date.today()
+
+    def delta(self):
+        if self.frequency == 'daily':
+            delta = relativedelta(days=1)
+        elif self.frequency == 'weekly':
+            delta = relativedelta(weeks=1, weekday=int(self.weekday.index))
+        elif self.frequency == 'monthly':
+            delta = relativedelta(months=1, day=self.day)
+        else:
+            delta = relativedelta()
+        return delta
+
+    def _rates(self, date, rounding=None):
+        pool = Pool()
+        Rate = pool.get('currency.currency.rate')
+        values = getattr(self, 'fetch_%s' % self.source)(date)
+
+        exp = Decimal(Decimal(1) / 10 ** Rate.rate.digits[1])
+        rates = Rate.search([
+                ('date', '=', date),
+                ])
+        code2rates = {r.currency.code: r for r in rates}
+
+        def get_rate(currency):
+            if currency.code in code2rates:
+                rate = code2rates[currency.code]
+            else:
+                rate = Rate(date=date, currency=currency)
+            return rate
+
+        rate = get_rate(self.currency)
+        rate.rate = Decimal(1).quantize(exp, rounding=rounding)
+        yield rate
+
+        for currency in self.currencies:
+            if currency.code not in values:
+                continue
+            value = values[currency.code]
+            rate = get_rate(currency)
+            rate.rate = value.quantize(exp, rounding=rounding)
+            yield rate
+
+    def fetch_ecb(self, date):
+        try:
+            return get_rates(self.currency.code, date)
+        except RatesNotAvailableError as e:
+            raise CronFetchError() from e
+
+
+class Cron_Currency(ModelSQL):
+    "Currency Cron - Currency"
+    __name__ = 'currency.cron-currency.currency'
+
+    cron = fields.Many2One(
+        'currency.cron', "Cron",
+        required=True, select=True, ondelete='CASCADE')
+    currency = fields.Many2One(
+        'currency.currency', "Currency",
+        required=True, ondelete='CASCADE')

currency.xml

@@ -98,5 +98,61 @@ this repository contains the full copyright notices and license terms. -->
             <field name="perm_delete" eval="True"/>
         </record>
 
+        <record model="ir.ui.view" id="cron_view_list">
+            <field name="model">currency.cron</field>
+            <field name="type">tree</field>
+            <field name="name">cron_list</field>
+        </record>
+
+        <record model="ir.ui.view" id="cron_view_form">
+            <field name="model">currency.cron</field>
+            <field name="type">form</field>
+            <field name="name">cron_form</field>
+        </record>
+
+        <record model="ir.action.act_window" id="act_cron_form">
+            <field name="name">Scheduled Rate Updates</field>
+            <field name="res_model">currency.cron</field>
+        </record>
+        <record model="ir.action.act_window.view" id="act_cron_form_view1">
+            <field name="sequence" eval="10"/>
+            <field name="view" ref="cron_view_list"/>
+            <field name="act_window" ref="act_cron_form"/>
+        </record>
+        <record model="ir.action.act_window.view" id="act_cron_form_view2">
+            <field name="sequence" eval="20"/>
+            <field name="view" ref="cron_view_form"/>
+            <field name="act_window" ref="act_cron_form"/>
+        </record>
+
+        <menuitem parent="menu_currency" action="act_cron_form" sequence="20" id="menu_cron_form"/>
+
+        <record model="ir.model.access" id="access_cron">
+            <field name="model" search="[('model', '=', 'currency.cron')]"/>
+            <field name="perm_read" eval="True"/>
+            <field name="perm_write" eval="False"/>
+            <field name="perm_create" eval="False"/>
+            <field name="perm_delete" eval="False"/>
+        </record>
+        <record model="ir.model.access" id="access_cron_currency_admin">
+            <field name="model" search="[('model', '=', 'currency.cron')]"/>
+            <field name="group" ref="group_currency_admin"/>
+            <field name="perm_read" eval="True"/>
+            <field name="perm_write" eval="True"/>
+            <field name="perm_create" eval="True"/>
+            <field name="perm_delete" eval="True"/>
+        </record>
+
+        <record model="ir.model.button" id="cron_run_button">
+            <field name="name">run</field>
+            <field name="string">Run</field>
+            <field name="model" search="[('model', '=', 'currency.cron')]"/>
+        </record>
+
+        <record model="ir.cron" id="cron_cron">
+            <field name="method">currency.cron|update</field>
+            <field name="interval_number" eval="1"/>
+            <field name="interval_type">days</field>
+        </record>
     </data>
 </tryton>

doc/design.rst

@@ -37,3 +37,23 @@ currencies.
 As exchange rates vary over time they are stored along with the date from
 when they apply.
 All exchange rates are relative with respect to each other.
+
+.. _model-currency.cron:
+
+Scheduled Rate Updates
+======================
+
+The `Exchange Rates <model-currency.rate>` can be automatically updated using a
+`Scheduled Task <trytond:model-ir.cron>`.
+When the scheduled task is run it uses the external source to fill in the
+missing rates since the last update.
+The frequency determines which dates get rates.
+
+.. seealso::
+
+   Scheduled Rate Updates can be found by opening the main menu item:
+
+      |Currency --> Scheduled Rate Updates|__
+
+      .. |Currency --> Scheduled Rate Updates| replace:: :menuselection:`Currency --> Scheduled Rate Updates`
+      __ https://demo.tryton.org/model/currency.cron

doc/usage.rst

@@ -35,3 +35,29 @@ the 15th of January you just need to set the rate on the USD currency to
    and 14th of January the last available rate will be used.
    Here this rate would be ``1.1222`` as this was the rate set for the 1st of
    January.
+
+.. _Scheduling rate updates:
+
+Scheduling rate updates
+=======================
+
+You may want to define some `Scheduled Rate Updates <model-currency.cron>` to
+keep the `Exchange Rates <model-currency.currency.rate>` up to date.
+When doing this you have to pick a source, the base `currency
+<model-currency.currency>` and a frequency.
+Then for each required date since the last update, a rate of ``1.0`` will be
+set for the base currency and the corresponding rate will be set for each of
+the selected currencies.
+
+.. warning::
+
+   It is strongly advised to use the same base currency for all *Scheduled Rate
+   Updates*.
+
+.. note::
+
+   The currency module only supports the rates provided by the `European
+   Central Bank`_, but third party modules can add additional sources for
+   exchange rates.
+
+.. _European Central Bank: https://www.ecb.europa.eu/stats/policy_and_exchange_rates/euro_reference_exchange_rates/html/index.en.html

ir.py

@@ -0,0 +1,13 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
+from trytond.pool import PoolMeta
+
+
+class Cron(metaclass=PoolMeta):
+    __name__ = 'ir.cron'
+
+    @classmethod
+    def __setup__(cls):
+        super().__setup__()
+        cls.method.selection.append(
+            ('currency.cron|update', "Update Currency Rates"))

setup.py

@@ -60,7 +60,7 @@ else:
 if local_version:
     version += '+' + '.'.join(local_version)
 
-requires = ['python-sql >= 0.9']
+requires = ['python-sql >= 0.9', 'python-dateutil']
 for dep in info.get('depends', []):
     if not re.match(r'(ir|res)(\W|$)', dep):
         requires.append(get_require_version('trytond_%s' % dep))
@@ -144,6 +144,7 @@ setup(name=name,
     extras_require={
         'data': [
             'pycountry', 'forex-python', get_require_version('proteus')],
+        'ecb_rate': ['forex-python'],
         },
     dependency_links=dependency_links,
     zip_safe=False,

tests/scenario_currency_rate_update.rst

@@ -0,0 +1,54 @@
+====================
+Currency Rate Update
+====================
+
+Imports::
+
+    >>> import datetime as dt
+    >>> from proteus import Model
+    >>> from trytond.tests.tools import activate_modules
+
+    >>> today = dt.date.today()
+    >>> yesterday = today - dt.timedelta(days=1)
+    >>> before_yesterday = yesterday - dt.timedelta(days=1)
+
+Activate modules::
+
+    >>> config = activate_modules('currency')
+
+Import models::
+
+    >>> Currency = Model.get('currency.currency')
+    >>> Cron = Model.get('currency.cron')
+
+Create some currencies::
+
+    >>> eur = Currency(name="Euro", code='EUR', symbol="€")
+    >>> eur.save()
+    >>> usd = Currency(name="U.S. Dollar", code='USD', symbol="$")
+    >>> usd.save()
+
+Setup cron::
+
+    >>> cron = Cron()
+    >>> cron.source = 'ecb'
+    >>> cron.frequency = 'daily'
+    >>> cron.day = None
+    >>> cron.currency = eur
+    >>> cron.currencies.append(Currency(usd.id))
+    >>> cron.last_update = before_yesterday
+    >>> cron.save()
+
+Run update::
+
+    >>> cron.click('run')
+    >>> cron.last_update >= yesterday
+    True
+
+    >>> eur.reload()
+    >>> rate, = [r for r in eur.rates if r.date == yesterday]
+    >>> rate.rate
+    Decimal('1.000000')
+    >>> rate, = [r for r in usd.rates if r.date == yesterday]
+    >>> bool(rate.rate)
+    True

tests/test_currency.py

@@ -303,4 +303,9 @@ def suite():
             tearDown=doctest_teardown, encoding='utf-8',
             checker=doctest_checker,
             optionflags=doctest.REPORT_ONLY_FIRST_FAILURE))
+    suite.addTests(doctest.DocFileSuite(
+            'scenario_currency_rate_update.rst',
+            tearDown=doctest_teardown, encoding='utf-8',
+            checker=doctest_checker,
+            optionflags=doctest.REPORT_ONLY_FIRST_FAILURE))
     return suite

view/cron_form.xml

@@ -0,0 +1,23 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<form>
+    <label name="source"/>
+    <field name="source"/>
+    <label name="frequency"/>
+    <group id="frequency" col="-1">
+        <field name="frequency"/>
+        <label name="weekday"/>
+        <field name="weekday"/>
+        <label name="day"/>
+        <field name="day"/>
+    </group>
+    <label name="currency"/>
+    <field name="currency"/>
+    <label name="last_update"/>
+    <group id="run">
+        <field name="last_update"/>
+        <button name="run"/>
+    </group>
+    <field name="currencies" colspan="4"/>
+</form>

view/cron_list.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<tree>
+    <field name="source" expand="1"/>
+    <field name="frequency"/>
+    <field name="currency"/>
+    <field name="last_update"/>
+</tree>