178 lines
5.2 KiB
ReStructuredText
178 lines
5.2 KiB
ReStructuredText
=========
|
|
Collector
|
|
=========
|
|
|
|
Data format
|
|
===========
|
|
|
|
Internally, CloudKitty's data format is a bit more detailled than what can be
|
|
found in the `architecture documentation`_.
|
|
|
|
The internal data format is the following:
|
|
|
|
.. code-block:: json
|
|
|
|
{
|
|
"bananas": [
|
|
{
|
|
"vol": {
|
|
"unit": "banana",
|
|
"qty": 1
|
|
},
|
|
"rating": {
|
|
"price": 1
|
|
},
|
|
"groupby": {
|
|
"xxx_id": "hello",
|
|
"yyy_id": "bye",
|
|
},
|
|
"metadata": {
|
|
"flavor": "chocolate",
|
|
"eaten_by": "gorilla",
|
|
},
|
|
}
|
|
],
|
|
}
|
|
|
|
However, developers implementing a collector don't need to format the data
|
|
themselves, as there are helper functions for these matters.
|
|
|
|
Implementation
|
|
==============
|
|
|
|
Each collector must implement the following class:
|
|
|
|
.. autoclass:: cloudkitty.collector.BaseCollector
|
|
:members: fetch_all, check_configuration
|
|
|
|
The ``retrieve`` method of the ``BaseCollector`` class is called by the
|
|
orchestrator. This method calls the ``fetch_all`` method of the child class.
|
|
|
|
To create a collector, you need to implement at least the ``fetch_all`` method.
|
|
|
|
|
|
Data collection
|
|
+++++++++++++++
|
|
|
|
Collectors must implement a ``fetch_all`` method. This method is called for
|
|
each metric type, for each scope, for each collect period. It has the
|
|
following prototype:
|
|
|
|
.. autoclass:: cloudkitty.collector.BaseCollector
|
|
:members: fetch_all
|
|
|
|
This method is supposed to return a list of objects formatted by
|
|
``CloudKittyFormatTransformer``.
|
|
|
|
Example code of a basic collector:
|
|
|
|
.. code-block:: python
|
|
|
|
from cloudkitty.collector import BaseCollector
|
|
|
|
class MyCollector(BaseCollector):
|
|
def __init__(self, **kwargs):
|
|
super(MyCollector, self).__init__(**kwargs)
|
|
|
|
def fetch_all(self, metric_name, start, end,
|
|
project_id=None, q_filter=None):
|
|
data = []
|
|
for CONDITION:
|
|
# do stuff
|
|
data.append(self.t_cloudkitty.format_item(
|
|
groupby, # dict
|
|
metadata, # dict
|
|
unit, # str
|
|
qty=qty, # int / float
|
|
))
|
|
|
|
return data
|
|
|
|
|
|
``project_id`` can be misleading, as it is a legacy name. It contains the
|
|
ID of the current scope. The attribute corresponding to the scope is specified
|
|
in the configuration, under ``[collect]/scope_key``. Thus, all queries should
|
|
filter based on this attribute. Example:
|
|
|
|
.. code-block:: python
|
|
|
|
from oslo_config import cfg
|
|
|
|
from cloudkitty.collector import BaseCollector
|
|
|
|
CONF = cfg.CONF
|
|
|
|
class MyCollector(BaseCollector):
|
|
def __init__(self, **kwargs):
|
|
super(MyCollector, self).__init__(**kwargs)
|
|
|
|
def fetch_all(self, metric_name, start, end,
|
|
project_id=None, q_filter=None):
|
|
scope_key = CONF.collect.scope_key
|
|
filters = {'start': start, 'stop': stop, scope_key: project_id}
|
|
|
|
data = self.client.query(
|
|
filters=filters,
|
|
groupby=self.conf[metric_name]['groupby'])
|
|
# Format data etc
|
|
return output
|
|
|
|
|
|
Additional configuration
|
|
++++++++++++++++++++++++
|
|
|
|
If you need to extend the metric configuration (add parameters to the
|
|
``extra_args`` section of ``metrics.yml``), you can overload the
|
|
``check_configuration`` method of the base collector:
|
|
|
|
.. autoclass:: cloudkitty.collector.BaseCollector
|
|
:members: check_configuration
|
|
|
|
This method uses `voluptuous`_ for data validation. The base schema for each
|
|
metric can be found in ``cloudkitty.collector.METRIC_BASE_SCHEMA``. This schema
|
|
is meant to be extended by other collectors. Example taken from the gnocchi
|
|
collector code:
|
|
|
|
.. code-block:: python
|
|
|
|
from cloudkitty import collector
|
|
|
|
GNOCCHI_EXTRA_SCHEMA = {
|
|
Required('extra_args'): {
|
|
Required('resource_type'): All(str, Length(min=1)),
|
|
# Due to Gnocchi model, metric are grouped by resource.
|
|
# This parameter allows to adapt the key of the resource identifier
|
|
Required('resource_key', default='id'): All(str, Length(min=1)),
|
|
Required('aggregation_method', default='max'):
|
|
In(['max', 'mean', 'min']),
|
|
},
|
|
}
|
|
|
|
class GnocchiCollector(collector.BaseCollector):
|
|
|
|
collector_name = 'gnocchi'
|
|
|
|
@staticmethod
|
|
def check_configuration(conf):
|
|
conf = collector.BaseCollector.check_configuration(conf)
|
|
metric_schema = Schema(collector.METRIC_BASE_SCHEMA).extend(
|
|
GNOCCHI_EXTRA_SCHEMA)
|
|
|
|
output = {}
|
|
for metric_name, metric in conf.items():
|
|
met = output[metric_name] = metric_schema(metric)
|
|
|
|
if met['extra_args']['resource_key'] not in met['groupby']:
|
|
met['groupby'].append(met['extra_args']['resource_key'])
|
|
|
|
return output
|
|
|
|
|
|
If your collector does not need any ``extra_args``, it is not required to
|
|
overload the ``check_configuration`` method.
|
|
|
|
|
|
.. _architecture documentation: ../admin/architecture.html
|
|
|
|
.. _voluptuous: https://github.com/alecthomas/voluptuous
|