[feature] Add a check which inspects device configuration status peri…

…odically #54

README.rst

@@ -247,6 +247,53 @@ in terms of disk space.
 
 Whether ping checks are created automatically for devices.
 
+``OPENWISP_MONITORING_AUTO_DEVICE_CONFIGURATION_MODIFIED``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
++--------------+-------------+
+| **type**:    | ``bool``    |
++--------------+-------------+
+| **default**: | ``True``    |
++--------------+-------------+
+
+``config_modified`` checks are run peridically to monitor whether device
+configuration is applied properly.
+This setting is used to govern whether ``config_modified`` checks are
+created automatically for newly registered devices.
+
+``OPENWISP_MONITORING_DEVICE_CONFIGURATION_MODIFIED_MAXIMUM_TIME``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
++--------------+-----------+
+| **type**:    |  ``int``  |
++--------------+-----------+
+| **default**: |   ``5``   |
++--------------+-----------+
+
+This setting allows you to configure the time that the check is allowed to
+fail after which the device health status changes to ``problem``.
+
+This default **duration** is 5 minutes. The input represents corresponding
+duration in minutes.
+
+**Note**: If the setting ``OPENWISP_MONITORING_AUTO_DEVICE_CONFIGURATION_MODIFIED``
+is disabled then this setting need not be declared.
+
+``OPENWISP_MONITORING_DEVICE_CONFIGURATION_MODIFIED_RETENTION_POLICY``
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
++--------------+-------------+
+| **type**:    |  ``time``   |
++--------------+-------------+
+| **default**: | ``48h0m0s`` |
++--------------+-------------+
+
+This setting allows to modify the duration for which the metric data generated
+by ``config_modified`` check is to be retained.
+
+**Note**: If the setting ``OPENWISP_MONITORING_AUTO_DEVICE_CONFIGURATION_MODIFIED``
+is disabled then this setting need not be declared.
+
 ``OPENWISP_MONITORING_AUTO_CHARTS``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

openwisp_monitoring/check/apps.py

@@ -1,8 +1,13 @@
 from django.apps import AppConfig
 from django.utils.translation import ugettext_lazy as _
 
+from .utils import manage_config_modified_retention_policy
+
 
 class CheckConfig(AppConfig):
     name = 'openwisp_monitoring.check'
     label = 'check'
     verbose_name = _('Network Monitoring Checks')
+
+    def ready(self):
+        manage_config_modified_retention_policy()

openwisp_monitoring/check/base/models.py

@@ -2,8 +2,9 @@
 
 from django.contrib.contenttypes.fields import GenericForeignKey
 from django.contrib.contenttypes.models import ContentType
-from django.db import models
+from django.db import models, transaction
 from django.db.models.signals import post_save
+from django.dispatch import receiver
 from django.utils.functional import cached_property
 from django.utils.module_loading import import_string
 from django.utils.translation import gettext_lazy as _
@@ -76,15 +77,13 @@ def perform_check(self, store=True):
 
 
 if app_settings.AUTO_PING:
-    from django.db import transaction
-    from django.dispatch import receiver
     from openwisp_monitoring.check.tasks import auto_create_ping
 
     @receiver(post_save, sender=Device, dispatch_uid='auto_ping')
     def auto_ping_receiver(sender, instance, created, **kwargs):
         """
         Implements OPENWISP_MONITORING_AUTO_PING
-        The creation step is executed in the backround
+        The creation step is executed in the background
         """
         # we need to skip this otherwise this task will be executed
         # every time the configuration is requested via checksum
@@ -96,6 +95,28 @@ def auto_ping_receiver(sender, instance, created, **kwargs):
                     model=sender.__name__.lower(),
                     app_label=sender._meta.app_label,
                     object_id=str(instance.pk),
-                    created=created,
+                )
+            )
+
+
+if app_settings.AUTO_CONFIG_MODIFIED:
+    from openwisp_monitoring.check.tasks import auto_create_config_modified
+
+    @receiver(post_save, sender=Device, dispatch_uid='auto_config_modified')
+    def auto_config_modified_receiver(sender, instance, created, **kwargs):
+        """
+        Implements OPENWISP_MONITORING_AUTO_CONFIG_MODIFIED
+        The creation step is executed in the background
+        """
+        # we need to skip this otherwise this task will be executed
+        # every time the configuration is requested via checksum
+        if not created:
+            return
+        with transaction.atomic():
+            transaction.on_commit(
+                lambda: auto_create_config_modified.delay(
+                    model=sender.__name__.lower(),
+                    app_label=sender._meta.app_label,
+                    object_id=str(instance.pk),
                 )
             )

openwisp_monitoring/check/classes/__init__.py

@@ -1 +1,2 @@
+from .config_modified import ConfigModified  # noqa
 from .ping import Ping  # noqa

openwisp_monitoring/check/classes/base.py

@@ -0,0 +1,39 @@
+from django.contrib.contenttypes.models import ContentType
+from django.core.exceptions import ValidationError
+from swapper import load_model
+
+from openwisp_controller.config.models import Device
+
+Metric = load_model('monitoring', 'Metric')
+
+
+class BaseCheck(object):
+    def validate_instance(self):
+        # check instance is of type device
+        obj = self.related_object
+        if not obj or not isinstance(obj, Device):
+            message = 'A related device is required to perform this operation'
+            raise ValidationError({'content_type': message, 'object_id': message})
+
+    def _get_or_create_metric(self, field_name):
+        """
+        Gets or creates metric
+        """
+        check = self.check_instance
+        if check.object_id and check.content_type:
+            obj_id = check.object_id
+            ct = check.content_type
+        else:
+            obj_id = str(check.id)
+            ct = ContentType.objects.get(
+                app_label=check._meta.app_label, model=check.__class__.__name__.lower()
+            )
+        options = dict(
+            name=check.name,
+            object_id=obj_id,
+            content_type=ct,
+            field_name=field_name,
+            key=self.__class__.__name__.lower(),
+        )
+        metric, created = Metric.objects.get_or_create(**options)
+        return metric, created

openwisp_monitoring/check/classes/config_modified.py

@@ -0,0 +1,40 @@
+from swapper import load_model
+
+from ..settings import CONFIG_MODIFIED_MAX_TIME
+from ..utils import CONFIG_MODIFIED_RP
+from .base import BaseCheck
+
+AlertSettings = load_model('monitoring', 'AlertSettings')
+
+
+class ConfigModified(BaseCheck):
+    def __init__(self, check, params):
+        self.check_instance = check
+        self.related_object = check.content_object
+        self.params = params
+
+    def validate(self):
+        self.validate_instance()
+
+    def check(self, store=True):
+        if not hasattr(self.related_object, 'config'):
+            return
+        result = 0 if self.related_object.config.status == 'applied' else 1
+        if store:
+            self.get_metric().write(
+                result, retention_policy=CONFIG_MODIFIED_RP,
+            )
+        return result
+
+    def get_metric(self):
+        metric, created = self._get_or_create_metric(field_name='config_modified')
+        if created:
+            self._create_alert_setting(metric)
+        return metric
+
+    def _create_alert_setting(self, metric):
+        alert_s = AlertSettings(
+            metric=metric, operator='>', value=0, seconds=CONFIG_MODIFIED_MAX_TIME * 60
+        )
+        alert_s.full_clean()
+        alert_s.save()

openwisp_monitoring/check/classes/ping.py

@@ -1,25 +1,23 @@
 import subprocess
 
-from django.contrib.contenttypes.models import ContentType
 from django.core.exceptions import ValidationError
 from jsonschema import draft7_format_checker, validate
 from jsonschema.exceptions import ValidationError as SchemaError
 from swapper import load_model
 
-from openwisp_controller.config.models import Device
-
 from ... import settings as monitoring_settings
 from .. import settings as app_settings
 from ..exceptions import OperationalError
+from .base import BaseCheck
 
 Chart = load_model('monitoring', 'Chart')
 Metric = load_model('monitoring', 'Metric')
 AlertSettings = load_model('monitoring', 'AlertSettings')
 
 
-class Ping(object):
+class Ping(BaseCheck):
     schema = {
-        '$schema': 'http://json-schema.org/draft-04/schema#',
+        '$schema': 'http://json-schema.org/draft-07/schema#',
         'type': 'object',
         'additionalProperties': False,
         'properties': {
@@ -57,13 +55,6 @@ def validate(self):
         self.validate_instance()
         self.validate_params()
 
-    def validate_instance(self):
-        # check instance is of type device
-        obj = self.related_object
-        if not obj or not isinstance(obj, Device):
-            message = 'A related device is required ' 'to perform this operation'
-            raise ValidationError({'content_type': message, 'object_id': message})
-
     def validate_params(self):
         try:
             validate(self.params, self.schema, format_checker=draft7_format_checker)
@@ -165,23 +156,7 @@ def _get_metric(self):
         """
         Gets or creates metric
         """
-        check = self.check_instance
-        if check.object_id and check.content_type:
-            obj_id = check.object_id
-            ct = check.content_type
-        else:
-            obj_id = str(check.id)
-            ct = ContentType.objects.get(
-                app_label=check._meta.app_label, model=check.__class__.__name__.lower()
-            )
-        options = dict(
-            name=check.name,
-            object_id=obj_id,
-            content_type=ct,
-            field_name='reachable',
-            key=self.__class__.__name__.lower(),
-        )
-        metric, created = Metric.objects.get_or_create(**options)
+        metric, created = self._get_or_create_metric(field_name='reachable')
         if created:
             self._create_alert_settings(metric)
             self._create_charts(metric)

openwisp_monitoring/check/migrations/0001_initial.py

@@ -9,6 +9,8 @@
 import collections
 import swapper
 
+from ..settings import CHECK_CLASSES
+
 
 class Migration(migrations.Migration):
 
@@ -58,7 +60,7 @@ class Migration(migrations.Migration):
                 (
                     'check',
                     models.CharField(
-                        choices=[('openwisp_monitoring.check.classes.Ping', 'Ping')],
+                        choices=CHECK_CLASSES,
                         db_index=True,
                         help_text='Select check type',
                         max_length=128,

openwisp_monitoring/check/migrations/0003_create_ping.py

@@ -11,7 +11,6 @@ def create_device_ping(apps, schema_editor):
                 model=Device.__name__.lower(),
                 app_label=Device._meta.app_label,
                 object_id=str(device.pk),
-                created=True,
             )
 
 

openwisp_monitoring/check/migrations/0004_create_config_modified.py

@@ -0,0 +1,33 @@
+from django.db import migrations
+from openwisp_monitoring.check.settings import AUTO_CONFIG_MODIFIED
+from openwisp_monitoring.check.tasks import auto_create_config_modified
+
+
+def add_config_modified_checks(apps, schema_editor):
+    if not AUTO_CONFIG_MODIFIED:
+        return
+    Device = apps.get_model('config', 'Device')
+    for device in Device.objects.all():
+        auto_create_config_modified.delay(
+            model=Device.__name__.lower(),
+            app_label=Device._meta.app_label,
+            object_id=str(device.pk),
+        )
+
+
+def remove_config_modified_checks(apps, schema_editor):
+    Check = apps.get_model('config', 'Device')
+    Check.objects.filter(name='Configuration Modified').delete()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('check', '0003_create_ping'),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            add_config_modified_checks, reverse_code=remove_config_modified_checks
+        ),
+    ]

openwisp_monitoring/check/settings.py

@@ -3,7 +3,22 @@
 CHECK_CLASSES = getattr(
     settings,
     'OPENWISP_MONITORING_CHECK_CLASSES',
-    (('openwisp_monitoring.check.classes.Ping', 'Ping'),),
+    (
+        ('openwisp_monitoring.check.classes.Ping', 'Ping'),
+        ('openwisp_monitoring.check.classes.ConfigModified', 'Configuration Modified'),
+    ),
 )
 AUTO_PING = getattr(settings, 'OPENWISP_MONITORING_AUTO_PING', True)
+AUTO_CONFIG_MODIFIED = getattr(
+    settings, 'OPENWISP_MONITORING_AUTO_DEVICE_CONFIGURATION_MODIFIED', True
+)
+# Input in minutes
+CONFIG_MODIFIED_MAX_TIME = getattr(
+    settings, 'OPENWISP_MONITORING_DEVICE_CONFIGURATION_MODIFIED_MAXIMUM_TIME', 5
+)
+CONFIG_MODIFIED_RETENTION_POLICY = getattr(
+    settings,
+    'OPENWISP_MONITORING_DEVICE_CONFIGURATION_MODIFIED_RETENTION_POLICY',
+    '48h0m0s',
+)
 MANAGEMENT_IP_ONLY = getattr(settings, 'OPENWISP_MONITORING_MANAGEMENT_IP_ONLY', True)