Grafana
- Canonical Observability
Channel | Revision | Published | Runs on |
---|---|---|---|
latest/stable | 117 | 10 Sep 2024 | |
latest/candidate | 117 | 28 Jun 2024 | |
latest/beta | 117 | 21 Jun 2024 | |
latest/edge | 121 | 18 Oct 2024 | |
1.0/stable | 93 | 12 Dec 2023 | |
1.0/candidate | 93 | 22 Nov 2023 | |
1.0/beta | 93 | 22 Nov 2023 | |
1.0/edge | 93 | 22 Nov 2023 |
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Platform:
charms.grafana_k8s.v0.grafana_dashboard
-
- Last updated 11 Jun 2024
- Revision Library version 0.36
Overview.
This document explains how to integrate with the Grafana charm
for the purpose of providing a dashboard which can be used by
end users. It also explains the structure of the data
expected by the grafana-dashboard
interface, and may provide a
mechanism or reference point for providing a compatible interface
or library by providing a definitive reference guide to the
structure of relation data which is shared between the Grafana
charm and any charm providing datasource information.
Provider Library Usage
The Grafana charm interacts with its dashboards using its charm
library. The goal of this library is to be as simple to use as
possible, and instantiation of the class with or without changing
the default arguments provides a complete use case. For the simplest
use case of a charm which bundles dashboards and provides a
provides: grafana-dashboard
interface,
requires:
grafana-dashboard:
interface: grafana_dashboard
creation of a GrafanaDashboardProvider
object with the default arguments is
sufficient.
:class:GrafanaDashboardProvider
expects that bundled dashboards should
be included in your charm with a default path of:
path/to/charm.py
path/to/src/grafana_dashboards/*.{json|json.tmpl|.tmpl}
Where the files are Grafana dashboard JSON data either from the Grafana marketplace, or directly exported from a Grafana instance. Refer to the official docs for more information.
When constructing a dashboard that is intended to be consumed by COS, make sure to use variables for your datasources, and name them "prometheusds" and "lokids". You can also use the following juju topology variables in your dashboards: $juju_model, $juju_model_uuid, $juju_application and $juju_unit. Note, however, that if metrics are coming via peripheral charms (scrape-config or cos-config) then topology labels would not exist.
The default constructor arguments are:
`charm`: `self` from the charm instantiating this library
`relation_name`: grafana-dashboard
`dashboards_path`: "/src/grafana_dashboards"
If your configuration requires any changes from these defaults, they may be set from the class constructor. It may be instantiated as follows:
from charms.grafana_k8s.v0.grafana_dashboard import GrafanaDashboardProvider
class FooCharm:
def __init__(self, *args):
super().__init__(*args, **kwargs)
...
self.grafana_dashboard_provider = GrafanaDashboardProvider(self)
...
The first argument (self
) should be a reference to the parent (providing
dashboards), as this charm's lifecycle events will be used to re-submit
dashboard information if a charm is upgraded, the pod is restarted, or other.
An instantiated GrafanaDashboardProvider
validates that the path specified
in the constructor (or the default) exists, reads the file contents, then
compresses them with LZMA and adds them to the application relation data
when a relation is established with Grafana.
Provided dashboards will be checked by Grafana, and a series of dropdown menus providing the ability to select query targets by Juju Model, application instance, and unit will be added if they do not exist.
To avoid requiring jinja
in GrafanaDashboardProvider
users, template validation
and rendering occurs on the other side of the relation, and relation data in
the form of:
{
"event": {
"valid": `true|false`,
"errors": [],
}
}
Will be returned if rendering or validation fails. In this case, the
GrafanaDashboardProvider
object will emit a dashboard_status_changed
event
of the type :class:GrafanaDashboardEvent
, which will contain information
about the validation error.
This information is added to the relation data for the charms as serialized JSON from a dict, with a structure of:
{
"application": {
"dashboards": {
"uuid": a uuid generated to ensure a relation event triggers,
"templates": {
"file:{hash}": {
"content": `{compressed_template_data}`,
"charm": `charm.meta.name`,
"juju_topology": {
"model": `charm.model.name`,
"model_uuid": `charm.model.uuid`,
"application": `charm.app.name`,
"unit": `charm.unit.name`,
}
},
"file:{other_file_hash}": {
...
},
},
},
},
}
This is ingested by :class:GrafanaDashboardConsumer
, and is sufficient for configuration.
The COS Configuration Charm can be used to add dashboards which are not bundled with charms.
Consumer Library Usage
The GrafanaDashboardConsumer
object may be used by Grafana
charms to manage relations with available dashboards. For this
purpose, a charm consuming Grafana dashboard information should do
the following things:
- Instantiate the
GrafanaDashboardConsumer
object by providing it a reference to the parent (Grafana) charm and, optionally, the name of the relation that the Grafana charm uses to interact with dashboards. This relation must confirm to thegrafana-dashboard
interface.
For example a Grafana charm may instantiate the
GrafanaDashboardConsumer
in its constructor as follows
from charms.grafana_k8s.v0.grafana_dashboard import GrafanaDashboardConsumer
def __init__(self, *args):
super().__init__(*args)
...
self.grafana_dashboard_consumer = GrafanaDashboardConsumer(self)
...
A Grafana charm also needs to listen to the
GrafanaDashboardConsumer
events emitted by theGrafanaDashboardConsumer
by adding itself as an observer for these events:self.framework.observe( self.grafana_source_consumer.on.sources_changed, self._on_dashboards_changed, )
Dashboards can be retrieved the :meth:dashboards
:
It will be returned in the format of:
[
{
"id": unique_id,
"relation_id": relation_id,
"charm": the name of the charm which provided the dashboard,
"content": compressed_template_data
},
]
The consuming charm should decompress the dashboard.
Index
class RelationNotFoundError
Description
Raised if there is no relation with the given name. None
Methods
RelationNotFoundError. __init__( self , relation_name: str )
class RelationInterfaceMismatchError
Description
Raised if the relation with the given name has a different interface. None
Methods
RelationInterfaceMismatchError. __init__( self , relation_name: str , expected_relation_interface: str , actual_relation_interface: str )
class RelationRoleMismatchError
Description
Raised if the relation with the given name has a different direction. None
Methods
RelationRoleMismatchError. __init__( self , relation_name: str , expected_relation_role: RelationRole , actual_relation_role: RelationRole )
class InvalidDirectoryPathError
Description
Raised if the grafana dashboards folder cannot be found or is otherwise invalid. None
Methods
InvalidDirectoryPathError. __init__( self , grafana_dashboards_absolute_path: str , message: str )
class GrafanaDashboardsChanged
Description
Event emitted when Grafana dashboards change. None
Methods
GrafanaDashboardsChanged. __init__( self , handle , data )
GrafanaDashboardsChanged. snapshot( self )
Description
Save grafana source information. None
GrafanaDashboardsChanged. restore( self , snapshot )
Description
Restore grafana source information. None
class GrafanaDashboardEvents
Description
Events raised by :class:GrafanaSourceEvents
. None
class GrafanaDashboardEvent
Event emitted when Grafana dashboards cannot be resolved.
Description
Enables us to set a clear status on the provider.
Methods
GrafanaDashboardEvent. __init__( self , handle , errors , valid: bool )
GrafanaDashboardEvent. snapshot( self )
Description
Save grafana source information. None
GrafanaDashboardEvent. restore( self , snapshot )
Description
Restore grafana source information. None
class GrafanaProviderEvents
Description
Events raised by :class:GrafanaSourceEvents
. None
class GrafanaDashboardProvider
Description
An API to provide Grafana dashboards to a Grafana charm. None
Methods
GrafanaDashboardProvider. __init__( self , charm: CharmBase , relation_name: str , dashboards_path: str )
API to provide Grafana dashboard to a Grafana charmed operator.
Arguments
a :class:CharmBase
object which manages this
:class:GrafanaProvider
object. Generally this is
self
in the instantiating class.
a :string: name of the relation managed by this
:class:GrafanaDashboardProvider
; it defaults to "grafana-dashboard".
a filesystem path relative to the charm root
where dashboard templates can be located. By default, the library
expects dashboard files to be in the <charm-py-directory>/grafana_dashboards
directory.
Description
The :class:GrafanaDashboardProvider
object provides an API
to upload dashboards to a Grafana charm. In its most streamlined
usage, the :class:GrafanaDashboardProvider
is integrated in a
charmed operator as follows:
self.grafana = GrafanaDashboardProvider(self)
The :class:GrafanaDashboardProvider
will look for dashboard
templates in the <charm-py-directory>/grafana_dashboards
folder.
Additionally, dashboard templates can be uploaded programmatically
via the :method:GrafanaDashboardProvider.add_dashboard
method.
To use the :class:GrafanaDashboardProvider
API, you need a relation
defined in your charm operator's metadata.yaml as follows:
provides:
grafana-dashboard:
interface: grafana_dashboard
If you would like to use relation name other than grafana-dashboard
,
you will need to specify the relation name via the relation_name
argument when instantiating the :class:GrafanaDashboardProvider
object.
However, it is strongly advised to keep the default relation name,
so that people deploying your charm will have a consistent experience
with all other charms that provide Grafana dashboards.
It is possible to provide a different file path for the Grafana dashboards
to be automatically managed by the :class:GrafanaDashboardProvider
object
via the dashboards_path
argument. This may be necessary when the directory
structure of your charmed operator repository is not the "usual" one as
generated by charmcraft init
, for example when adding the charmed operator
in a Java repository managed by Maven or Gradle. However, unless there are
such constraints with other tooling, it is strongly advised to store the
Grafana dashboards in the default <charm-py-directory>/grafana_dashboards
folder, in order to provide a consistent experience for other charmed operator
authors.
GrafanaDashboardProvider. add_dashboard( self , content: str , inject_dropdowns: bool )
Add a dashboard to the relation managed by this :class:GrafanaDashboardProvider
.
Arguments
a string representing a Jinja template. Currently, no global variables are added to the Jinja template evaluation context.
a :boolean: indicating whether topology dropdowns should be added to the dashboard
GrafanaDashboardProvider. remove_non_builtin_dashboards( self )
Description
Remove all dashboards to the relation added via :method:add_dashboard
. None
GrafanaDashboardProvider. update_dashboards( self )
Description
Trigger the re-evaluation of the data on all relations. None
GrafanaDashboardProvider. dashboard_templates( self )
Description
Return a list of the known dashboard templates. None
class GrafanaDashboardConsumer
Description
A consumer object for working with Grafana Dashboards. None
Methods
GrafanaDashboardConsumer. __init__( self , charm: CharmBase , relation_name: str )
API to receive Grafana dashboards from charmed operators.
Description
The :class:GrafanaDashboardConsumer
object provides an API
to consume dashboards provided by a charmed operator using the
GrafanaDashboardConsumer. get_dashboards_from_relation( self , relation_id: int )
Get a list of known dashboards for one instance of the monitored relation.
Arguments
the identifier of the relation instance, as returned by
:method:ops.model.Relation.id
.
GrafanaDashboardConsumer. update_dashboards( self , relation )
Re-establish dashboards on one or more relations.
Arguments
a specific relation for which the dashboards have to be
updated. If not specified, all relations managed by this
:class:GrafanaDashboardConsumer
will be updated.
Description
If something changes between this library and a datasource, try to re-establish invalid dashboards and invalidate active ones.
GrafanaDashboardConsumer. dashboards( self )
Get a list of known dashboards across all instances of the monitored relation.
Description
Returns: a list of known dashboards. The JSON of each of the dashboards is available
in the content
field of the corresponding dict
.
GrafanaDashboardConsumer. set_peer_data( self , key: str , data: Any )
Description
Put information into the peer data bucket instead of StoredState
. None
GrafanaDashboardConsumer. get_peer_data( self , key: str )
Description
Retrieve information from the peer data bucket instead of StoredState
. None
class GrafanaDashboardAggregator
API to retrieve Grafana dashboards from machine dashboards.
Arguments
a :class:CharmBase
object which manages this
:class:GrafanaProvider
object. Generally this is
self
in the instantiating class.
a :string: name of a relation managed by this
:class:GrafanaDashboardAggregator
, which is used to communicate
with reactive/machine charms it defaults to "dashboards".
a :string: name of a relation used by this
:class:GrafanaDashboardAggregator
, which is used to communicate
with charmed grafana. It defaults to "downstream-grafana-dashboard"
Description
The :class:GrafanaDashboardAggregator
object provides a way to
collate and aggregate Grafana dashboards from reactive/machine charms
and transport them into Charmed Operators, using Juju topology.
For detailed usage instructions, see the documentation for
:module:cos-proxy-operator
, as this class is intended for use as a
single point of intersection rather than use in individual charms.
Since :class:GrafanaDashboardAggregator
serves as a bridge between
Canonical Observability Stack Charmed Operators and Reactive Charms,
deployed in a Reactive Juju model, both a target relation which is
used to collect events from Reactive charms and a grafana_relation
which is used to send the collected data back to the Canonical
Observability Stack are required.
In its most streamlined usage, :class:GrafanaDashboardAggregator
is
integrated in a charmed operator as follows:
self.grafana = GrafanaDashboardAggregator(self)
Methods
GrafanaDashboardAggregator. __init__( self , charm: CharmBase , target_relation: str , grafana_relation: str )
GrafanaDashboardAggregator. update_dashboards( self , event: RelationEvent )
Description
If we get a dashboard from a reactive charm, parse it out and update. None
GrafanaDashboardAggregator. remove_dashboards( self , event: RelationBrokenEvent )
Description
Remove a dashboard if the relation is broken. None
class CosTool
Description
Uses cos-tool to inject label matchers into alert rule expressions and validate rules. None
Methods
CosTool. __init__( self , charm )
CosTool. path( self )
Description
Lazy lookup of the path of cos-tool. None
CosTool. apply_label_matchers( self , rules: dict , type: str )
Description
Will apply label matchers to the expression of all alerts in all supplied groups. None
CosTool. validate_alert_rules( self , rules: dict )
Description
Will validate correctness of alert rules, returning a boolean and any errors. None
CosTool. inject_label_matchers( self , expression: str , topology: dict , type: str )
Description
Add label matchers to an expression. None