Code Utilities

Note

This page is for developers who want to customize or extend OpenWISP Monitoring, whether for bug fixes, new features, or contributions.

For user guides and general information, please see:

Registering / Unregistering Metric Configuration

OpenWISP Monitoring provides registering and unregistering metric configuration through utility functions openwisp_monitoring.monitoring.configuration.register_metric and openwisp_monitoring.monitoring.configuration.unregister_metric. Using these functions you can register or unregister metric configurations from anywhere in your code.

`register_metric`

This function is used to register a new metric configuration from anywhere in your code.

Parameter	Description
metric_name:	A `str` defining name of the metric configuration.
metric_configuration:	A `dict` defining configuration of the metric.

An example usage has been shown below.

from django.utils.translation import gettext_lazy as _
from openwisp_monitoring.monitoring.configuration import register_metric

# Define configuration of your metric
metric_config = {
    "label": _("Ping"),
    "name": "Ping",
    "key": "ping",
    "field_name": "reachable",
    "related_fields": ["loss", "rtt_min", "rtt_max", "rtt_avg"],
    "charts": {
        "uptime": {
            "type": "bar",
            "title": _("Ping Success Rate"),
            "description": _(
                "A value of 100% means reachable, 0% means unreachable, values in "
                "between 0% and 100% indicate the average reachability in the "
                "period observed. Obtained with the fping linux program."
            ),
            "summary_labels": [_("Average Ping Success Rate")],
            "unit": "%",
            "order": 200,
            "colorscale": {
                "max": 100,
                "min": 0,
                "label": _("Rate"),
                "scale": [
                    [
                        [0, "#c13000"],
                        [0.1, "cb7222"],
                        [0.5, "#deed0e"],
                        [0.9, "#7db201"],
                        [1, "#498b26"],
                    ],
                ],
                "map": [
                    [100, "#498b26", _("Flawless")],
                    [90, "#7db201", _("Mostly Reachable")],
                    [50, "#deed0e", _("Partly Reachable")],
                    [10, "#cb7222", _("Mostly Unreachable")],
                    [None, "#c13000", _("Unreachable")],
                ],
                "fixed_value": 100,
            },
            "query": chart_query["uptime"],
        },
        "packet_loss": {
            "type": "bar",
            "title": _("Packet loss"),
            "description": _(
                "Indicates the percentage of lost packets observed in ICMP probes. "
                "Obtained with the fping linux program."
            ),
            "summary_labels": [_("Average packet loss")],
            "unit": "%",
            "colors": "#d62728",
            "order": 210,
            "query": chart_query["packet_loss"],
        },
        "rtt": {
            "type": "scatter",
            "title": _("Round Trip Time"),
            "description": _(
                "Round trip time observed in ICMP probes, measuered in milliseconds."
            ),
            "summary_labels": [
                _("Average RTT"),
                _("Average Max RTT"),
                _("Average Min RTT"),
            ],
            "unit": _(" ms"),
            "order": 220,
            "query": chart_query["rtt"],
        },
    },
    "alert_settings": {"operator": "<", "threshold": 1, "tolerance": 0},
    "notification": {
        "problem": {
            "verbose_name": "Ping PROBLEM",
            "verb": "cannot be reached anymore",
            "level": "warning",
            "email_subject": _(
                "[{site.name}] {notification.target} is not reachable"
            ),
            "message": _(
                "The device [{notification.target}] {notification.verb} anymore by our ping "
                "messages."
            ),
        },
        "recovery": {
            "verbose_name": "Ping RECOVERY",
            "verb": "has become reachable",
            "level": "info",
            "email_subject": _(
                "[{site.name}] {notification.target} is reachable again"
            ),
            "message": _(
                "The device [{notification.target}] {notification.verb} again by our ping "
                "messages."
            ),
        },
    },
}

# Register your custom metric configuration
register_metric("ping", metric_config)

The above example will register one metric configuration (named ping), three chart configurations (named rtt, packet_loss, uptime) as defined in the charts key, two notification types (named ping_recovery, ping_problem) as defined in notification key.

The AlertSettings of ping metric will by default use threshold and tolerance defined in the alert_settings key. You can always override them and define your own custom values via the admin.

You can also use the alert_field key in metric configuration which allows AlertSettings to check the threshold on alert_field instead of the default field_name key.

Note

It will raise ImproperlyConfigured exception if a metric configuration is already registered with same name (not to be confused with verbose_name).

If you don't need to register a new metric but need to change a specific key of an existing metric configuration, you can use OPENWISP_MONITORING_METRICS.

`unregister_metric`

This function is used to unregister a metric configuration from anywhere in your code.

Parameter	Description
metric_name:	A `str` defining name of the metric configuration.

An example usage is shown below.

from openwisp_monitoring.monitoring.configuration import unregister_metric

# Unregister previously registered metric configuration
unregister_metric("metric_name")

Note

It will raise ImproperlyConfigured exception if the concerned metric configuration is not registered.

Registering / Unregistering Chart Configuration

OpenWISP Monitoring provides registering and unregistering chart configuration through utility functions openwisp_monitoring.monitoring.configuration.register_chart and openwisp_monitoring.monitoring.configuration.unregister_chart. Using these functions you can register or unregister chart configurations from anywhere in your code.

`register_chart`

This function is used to register a new chart configuration from anywhere in your code.

Parameter	Description
chart_name:	A `str` defining name of the chart configuration.
chart_configuration:	A `dict` defining configuration of the chart.

An example usage has been shown below.

from openwisp_monitoring.monitoring.configuration import register_chart

# Define configuration of your chart
chart_config = {
    "type": "histogram",
    "title": "Histogram",
    "description": "Histogram",
    "top_fields": 2,
    "order": 999,
    "query": {
        "influxdb": (
            "SELECT {fields|SUM|/ 1} FROM {key} "
            "WHERE time >= '{time}' AND content_type = "
            "'{content_type}' AND object_id = '{object_id}'"
        )
    },
}

# Register your custom chart configuration
register_chart("chart_name", chart_config)

Note

It will raise ImproperlyConfigured exception if a chart configuration is already registered with same name (not to be confused with verbose_name).

If you don't need to register a new chart but need to change a specific key of an existing chart configuration, you can use OPENWISP_MONITORING_CHARTS.

`unregister_chart`

This function is used to unregister a chart configuration from anywhere in your code.

Parameter	Description
chart_name:	A `str` defining name of the chart configuration.

An example usage is shown below.

from openwisp_monitoring.monitoring.configuration import unregister_chart

# Unregister previously registered chart configuration
unregister_chart("chart_name")

Note

It will raise ImproperlyConfigured exception if the concerned chart configuration is not registered.

Monitoring Notifications

OpenWISP Monitoring registers and uses the following notification types:

threshold_crossed: Fires when a metric crosses the boundary defined in the threshold value of the alert settings.
threhold_recovery: Fires when a metric goes back within the expected range.
connection_is_working: Fires when the connection to a device is working.
connection_is_not_working: Fires when the connection (e.g.: SSH) to a device stops working (e.g.: credentials are outdated, management IP address is outdated, or device is not reachable).

Registering Notification Types

You can define your own notification types using register_notification_type function from OpenWISP Notifications.

For more information, see the relevant documentation section about registering notification types in the Notifications module.

Once a new notification type is registered, you have to use the "notify" signal provided the Notifications module to send notifications for this type.

Signals

Note

If you're not familiar with signals, please refer to the Django Signals documentation.

`device_metrics_received`

Full Python path: openwisp_monitoring.device.signals.device_metrics_received

Arguments:

instance: instance of Device whose metrics have been received
request: the HTTP request object
time: time with which metrics will be saved. If none, then server time will be used
current: whether the data has just been collected or was collected previously and sent now due to network connectivity issues

This signal is emitted when device metrics are received to the DeviceMetric view (only when using HTTP POST).

The signal is emitted just before a successful response is returned, it is not sent if the response was not successful.

`health_status_changed`

Full Python path: openwisp_monitoring.device.signals.health_status_changed

Arguments:

instance: instance of DeviceMonitoring whose status has been changed
status: the status by which DeviceMonitoring's existing status has been updated with

This signal is emitted only if the health status of DeviceMonitoring object gets updated.

`threshold_crossed`

Full Python path: openwisp_monitoring.monitoring.signals.threshold_crossed

Arguments:

metric: Metric object whose threshold defined in related alert settings was crossed
alert_settings: AlertSettings related to the Metric
target: related Device object
first_time: it will be set to true when the metric is written for the first time. It shall be set to false afterwards.
tolerance_crossed: it will be set to true if the metric has crossed the threshold for tolerance configured in alert settings. Otherwise, it will be set to false.

first_time parameter can be used to avoid initiating unneeded actions. For example, sending recovery notifications.

This signal is emitted when the threshold value of a Metric defined in alert settings is crossed.

`pre_metric_write`

Full Python path: openwisp_monitoring.monitoring.signals.pre_metric_write

Arguments:

metric: Metric object whose data shall be stored in timeseries database
values: metric data that shall be stored in the timeseries database
time: time with which metrics will be saved
current: whether the data has just been collected or was collected previously and sent now due to network connectivity issues

This signal is emitted for every metric before the write operation is sent to the timeseries database.

`post_metric_write`

Full Python path: openwisp_monitoring.monitoring.signals.post_metric_write

Arguments:

metric: Metric object whose data is being stored in timeseries database
values: metric data that is being stored in the timeseries database
time: time with which metrics will be saved
current: whether the data has just been collected or was collected previously and sent now due to network connectivity issues

This signal is emitted for every metric after the write operation is successfully executed in the background.

Exceptions

`TimeseriesWriteException`

Full Python path: openwisp_monitoring.db.exceptions.TimeseriesWriteException

If there is any failure due while writing data in timeseries database, this exception will be raised with a helpful error message explaining the cause of the failure. This exception will normally be caught and the failed write task will be retried in the background so that there is no loss of data if failures occur due to overload of Timeseries server. You can read more about this retry mechanism at OPENWISP_MONITORING_WRITE_RETRY_OPTIONS.

`InvalidMetricConfigException`

Full Python path: openwisp_monitoring.monitoring.exceptions.InvalidMetricConfigException

This exception will be raised if the metric configuration is broken.

`InvalidChartConfigException`

Full Python path: openwisp_monitoring.monitoring.exceptions.InvalidChartConfigException

This exception will be raised if the chart configuration is broken.

Developer Installation Instructions

Extending OpenWISP Monitoring