Add fields validation for CrontabSchedule (#154)

* ignore pyenv .python-version file

* add crontab validators

* add validators unittests

* py2.7 compatibility

* add python-crontab to default requirements

* use latest version of python-crontab

in 2.3+ all bugs were fixed but support for py3.3-3.4 was droped (judging by setup.py tags)

* 📝 rewrite crontab validation

* 📚 add validators reference file to docs

* 📚 include validators reference into index toctree

* 📝 add migration

* please linters

Author: vanyakosmos

.gitignore

@@ -30,3 +30,4 @@ cover/
 htmlcov/
 coverage.xml
 .eggs/
+.python-version

django_celery_beat/migrations/0008_auto_20180914_1922.py

@@ -0,0 +1,61 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 2.0.3 on 2018-09-14 19:22
+from __future__ import absolute_import, unicode_literals
+
+from django.db import migrations, models
+from django_celery_beat import validators
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('django_celery_beat', '0007_auto_20180521_0826'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='crontabschedule',
+            name='day_of_month',
+            field=models.CharField(
+                default='*', max_length=124,
+                validators=[validators.day_of_month_validator],
+                verbose_name='day of month'
+            ),
+        ),
+        migrations.AlterField(
+            model_name='crontabschedule',
+            name='day_of_week',
+            field=models.CharField(
+                default='*', max_length=64,
+                validators=[validators.day_of_week_validator],
+                verbose_name='day of week'
+            ),
+        ),
+        migrations.AlterField(
+            model_name='crontabschedule',
+            name='hour',
+            field=models.CharField(
+                default='*', max_length=96,
+                validators=[validators.hour_validator],
+                verbose_name='hour'
+            ),
+        ),
+        migrations.AlterField(
+            model_name='crontabschedule',
+            name='minute',
+            field=models.CharField(
+                default='*', max_length=240,
+                validators=[validators.minute_validator],
+                verbose_name='minute'
+            ),
+        ),
+        migrations.AlterField(
+            model_name='crontabschedule',
+            name='month_of_year',
+            field=models.CharField(
+                default='*', max_length=64,
+                validators=[validators.month_of_year_validator],
+                verbose_name='month of year'
+            ),
+        ),
+    ]

django_celery_beat/models.py

@@ -3,19 +3,18 @@
 
 from datetime import timedelta
 
+import timezone_field
+from celery import schedules
+from celery.five import python_2_unicode_compatible
 from django.core.exceptions import MultipleObjectsReturned, ValidationError
 from django.db import models
 from django.db.models import signals
 from django.utils.translation import ugettext_lazy as _
 
-from celery import schedules
-from celery.five import python_2_unicode_compatible
-
-from . import managers
+from . import managers, validators
 from .tzcrontab import TzAwareCrontab
-from .utils import now, make_aware
+from .utils import make_aware, now
 
-import timezone_field
 
 DAYS = 'days'
 HOURS = 'hours'
@@ -152,16 +151,25 @@ class CrontabSchedule(models.Model):
     # 4 chars for each value (what we save on 0-9 accomodates the []).
     # We leave the other fields at their historical length.
     #
-    minute = models.CharField(_('minute'), max_length=60 * 4, default='*')
-    hour = models.CharField(_('hour'), max_length=24 * 4, default='*')
+    minute = models.CharField(
+        _('minute'), max_length=60 * 4, default='*',
+        validators=[validators.minute_validator],
+    )
+    hour = models.CharField(
+        _('hour'), max_length=24 * 4, default='*',
+        validators=[validators.hour_validator],
+    )
     day_of_week = models.CharField(
         _('day of week'), max_length=64, default='*',
+        validators=[validators.day_of_week_validator],
     )
     day_of_month = models.CharField(
         _('day of month'), max_length=31 * 4, default='*',
+        validators=[validators.day_of_month_validator],
     )
     month_of_year = models.CharField(
         _('month of year'), max_length=64, default='*',
+        validators=[validators.month_of_year_validator],
     )
 
     timezone = timezone_field.TimeZoneField(default='UTC')

django_celery_beat/validators.py

@@ -0,0 +1,107 @@
+"""Validators."""
+from __future__ import absolute_import, unicode_literals
+
+import crontab
+from django.core.exceptions import ValidationError
+
+
+class _CronSlices(crontab.CronSlices):
+    """Cron slices with customized validation."""
+
+    def __init__(self, *args):
+        super(crontab.CronSlices, self).__init__(
+            [_CronSlice(info) for info in crontab.S_INFO]
+        )
+        self.special = None
+        self.setall(*args)
+        self.is_valid = self.is_self_valid
+
+    @classmethod
+    def validate(cls, *args):
+        try:
+            cls(*args)
+        except Exception as e:
+            raise ValueError(e)
+
+
+class _CronSlice(crontab.CronSlice):
+    """Cron slice with custom range parser."""
+
+    def get_range(self, *vrange):
+        ret = _CronRange(self, *vrange)
+        if ret.dangling is not None:
+            return [ret.dangling, ret]
+        return [ret]
+
+
+class _CronRange(crontab.CronRange):
+    """Cron range parser class."""
+
+    # rewrite whole method to raise error on bad range
+    def parse(self, value):
+        if value.count('/') == 1:
+            value, seq = value.split('/')
+            try:
+                self.seq = self.slice.parse_value(seq)
+            except crontab.SundayError:
+                self.seq = 1
+                value = "0-0"
+            if self.seq < 1 or self.seq > self.slice.max:
+                raise ValueError("Sequence can not be divided by zero or max")
+        if value.count('-') == 1:
+            vfrom, vto = value.split('-')
+            self.vfrom = self.slice.parse_value(vfrom, sunday=0)
+            try:
+                self.vto = self.slice.parse_value(vto)
+            except crontab.SundayError:
+                if self.vfrom == 1:
+                    self.vfrom = 0
+                else:
+                    self.dangling = 0
+                self.vto = self.slice.parse_value(vto, sunday=6)
+            if self.vto < self.vfrom:
+                raise ValueError("Bad range '{0.vfrom}-{0.vto}'".format(self))
+        elif value == '*':
+            self.all()
+        else:
+            raise ValueError('Unknown cron range value "%s"' % value)
+
+
+def crontab_validator(value):
+    """Validate crontab."""
+    try:
+        _CronSlices.validate(value)
+    except ValueError as e:
+        raise ValidationError(e)
+
+
+def minute_validator(value):
+    """Validate minutes crontab value."""
+    _validate_crontab(value, 0)
+
+
+def hour_validator(value):
+    """Validate hours crontab value."""
+    _validate_crontab(value, 1)
+
+
+def day_of_month_validator(value):
+    """Validate day of month crontab value."""
+    _validate_crontab(value, 2)
+
+
+def month_of_year_validator(value):
+    """Validate month crontab value."""
+    _validate_crontab(value, 3)
+
+
+def day_of_week_validator(value):
+    """Validate day of week crontab value."""
+    _validate_crontab(value, 4)
+
+
+def _validate_crontab(value, index):
+    tab = ['*'] * 5
+    tab[index] = value
+    tab = ' '.join(tab)
+    crontab_validator(tab)

docs/reference/django-celery-beat.validators.rst

@@ -0,0 +1,11 @@
+=====================================================
+ ``django_celery_beat.validators``
+=====================================================
+
+.. contents::
+    :local:
+.. currentmodule:: django_celery_beat.validators
+
+.. automodule:: django_celery_beat.validators
+    :members:
+    :undoc-members:

docs/reference/index.rst

@@ -17,3 +17,4 @@
     django-celery-beat.schedulers
     django-celery-beat.admin
     django-celery-beat.utils
+    django-celery-beat.validators

requirements/default.txt

@@ -1,2 +1,3 @@
 celery>=4.0,<5.0
 django-timezone-field>=2.0
+python-crontab>=2.3.4