Implement Prometheus fetcher

A Prometheus scope fetcher has been added in order to dynamically discover
scopes from a Prometheus service using a user defined metric and a scope
attribute.
It can also filter out the response from Prometheus using metadata filters
to have a more fine-grained control over scope discovery.
It features HTTP basic auth capabilities and HTTPS configuration options
similar to Prometheus collector.

Change-Id: If3c2da8d7949e0aec08f3699547faf34af4ddee4
Story: 2005427
Task: 30458

cloudkitty/collector/prometheus.py

@@ -18,13 +18,14 @@ from decimal import ROUND_HALF_UP
 
 from oslo_config import cfg
 from oslo_log import log
-import requests
 from voluptuous import In
 from voluptuous import Required
 from voluptuous import Schema
 
 from cloudkitty import collector
-from cloudkitty.collector import exceptions as collect_exceptions
+from cloudkitty.collector.exceptions import CollectError
+from cloudkitty.common.prometheus_client import PrometheusClient
+from cloudkitty.common.prometheus_client import PrometheusResponseError
 from cloudkitty import utils as ck_utils
 
 
@@ -72,60 +73,6 @@ PROMETHEUS_EXTRA_SCHEMA = {
 }
 
 
-class PrometheusResponseError(collect_exceptions.CollectError):
-    pass
-
-
-class PrometheusClient(object):
-    INSTANT_QUERY_ENDPOINT = 'query'
-    RANGE_QUERY_ENDPOINT = 'query_range'
-
-    def __init__(self, url, auth=None, verify=True):
-        self.url = url
-        self.auth = auth
-        self.verify = verify
-
-    def _get(self, endpoint, params):
-        return requests.get(
-            '{}/{}'.format(self.url, endpoint),
-            params=params,
-            auth=self.auth,
-            verify=self.verify,
-        )
-
-    def get_instant(self, query, time=None, timeout=None):
-        res = self._get(
-            self.INSTANT_QUERY_ENDPOINT,
-            params={'query': query, 'time': time, 'timeout': timeout},
-        )
-        try:
-            return res.json()
-        except ValueError:
-            raise PrometheusResponseError(
-                'Could not get a valid json response for '
-                '{} (response: {})'.format(res.url, res.text)
-            )
-
-    def get_range(self, query, start, end, step, timeout=None):
-        res = self._get(
-            self.RANGE_QUERY_ENDPOINT,
-            params={
-                'query': query,
-                'start': start,
-                'end': end,
-                'step': step,
-                'timeout': timeout,
-            },
-        )
-        try:
-            return res.json()
-        except ValueError:
-            raise PrometheusResponseError(
-                'Could not get a valid json response for '
-                '{} (response: {})'.format(res.url, res.text)
-            )
-
-
 class PrometheusCollector(collector.BaseCollector):
     collector_name = 'prometheus'
 
@@ -203,10 +150,14 @@ class PrometheusCollector(collector.BaseCollector):
             period,
             ', '.join(groupby + metadata),
         )
-        res = self._conn.get_instant(
+
-            query,
+        try:
-            time,
+            res = self._conn.get_instant(
-        )
+                query,
+                time,
+            )
+        except PrometheusResponseError as e:
+            raise CollectError(*e.args)
 
         # If the query returns an empty dataset,
         # return an empty list

cloudkitty/common/config.py

@@ -54,6 +54,8 @@ _opts = [
     ('fetcher_keystone', list(itertools.chain(
         cloudkitty.fetcher.keystone.keystone_opts,
         cloudkitty.fetcher.keystone.fetcher_keystone_opts))),
+    ('fetcher_prometheus', list(itertools.chain(
+        cloudkitty.fetcher.prometheus.fetcher_prometheus_opts))),
     ('fetcher_source', list(itertools.chain(
         cloudkitty.fetcher.source.fetcher_source_opts))),
     ('orchestrator', list(itertools.chain(

cloudkitty/common/prometheus_client.py

@@ -0,0 +1,69 @@
+# Copyright 2019 Objectif Libre
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+#
+import requests
+
+
+class PrometheusResponseError(Exception):
+    pass
+
+
+class PrometheusClient(object):
+    INSTANT_QUERY_ENDPOINT = 'query'
+    RANGE_QUERY_ENDPOINT = 'query_range'
+
+    def __init__(self, url, auth=None, verify=True):
+        self.url = url
+        self.auth = auth
+        self.verify = verify
+
+    def _get(self, endpoint, params):
+        return requests.get(
+            '{}/{}'.format(self.url, endpoint),
+            params=params,
+            auth=self.auth,
+            verify=self.verify,
+        )
+
+    def get_instant(self, query, time=None, timeout=None):
+        res = self._get(
+            self.INSTANT_QUERY_ENDPOINT,
+            params={'query': query, 'time': time, 'timeout': timeout},
+        )
+        try:
+            return res.json()
+        except ValueError:
+            raise PrometheusResponseError(
+                'Could not get a valid json response for '
+                '{} (response: {})'.format(res.url, res.text)
+            )
+
+    def get_range(self, query, start, end, step, timeout=None):
+        res = self._get(
+            self.RANGE_QUERY_ENDPOINT,
+            params={
+                'query': query,
+                'start': start,
+                'end': end,
+                'step': step,
+                'timeout': timeout,
+            },
+        )
+        try:
+            return res.json()
+        except ValueError:
+            raise PrometheusResponseError(
+                'Could not get a valid json response for '
+                '{} (response: {})'.format(res.url, res.text)
+            )

cloudkitty/fetcher/prometheus.py

@@ -0,0 +1,148 @@
+# -*- coding: utf-8 -*-
+# Copyright 2015 Objectif Libre
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+#
+from oslo_config import cfg
+
+from cloudkitty.common.prometheus_client import PrometheusClient
+from cloudkitty.common.prometheus_client import PrometheusResponseError
+from cloudkitty import fetcher
+
+
+class PrometheusFetcherError(Exception):
+    pass
+
+
+FETCHER_PROMETHEUS_OPTS = 'fetcher_prometheus'
+
+fetcher_prometheus_opts = [
+    cfg.StrOpt(
+        'metric',
+        help='Metric from which scope_ids should be requested',
+    ),
+    cfg.StrOpt(
+        'scope_attribute',
+        default='project_id',
+        help='Attribute from which scope_ids should be collected',
+    ),
+    cfg.StrOpt(
+        'prometheus_url',
+        help='Prometheus service URL',
+    ),
+    cfg.StrOpt(
+        'prometheus_user',
+        default='',
+        help='Prometheus user (for basic auth only)',
+    ),
+    cfg.StrOpt(
+        'prometheus_password',
+        default='',
+        help='Prometheus user (for basic auth only)',
+    ),
+    cfg.StrOpt(
+        'cafile',
+        help='Custom certificate authority file path',
+    ),
+    cfg.BoolOpt(
+        'insecure',
+        default=False,
+        help='Explicitly trust untrusted HTTPS responses',
+    ),
+    cfg.DictOpt(
+        'filters',
+        default=dict(),
+        help='Metadata to filter out the scope_ids discovery request response',
+    ),
+]
+
+cfg.CONF.register_opts(fetcher_prometheus_opts, FETCHER_PROMETHEUS_OPTS)
+
+CONF = cfg.CONF
+
+
+class PrometheusFetcher(fetcher.BaseFetcher):
+    """Prometheus scope_id fetcher"""
+
+    name = 'prometheus'
+
+    def __init__(self):
+        super(PrometheusFetcher, self).__init__()
+        url = CONF.fetcher_prometheus.prometheus_url
+
+        user = CONF.fetcher_prometheus.prometheus_user
+        password = CONF.fetcher_prometheus.prometheus_password
+
+        verify = True
+        if CONF.fetcher_prometheus.cafile:
+            verify = CONF.fetcher_prometheus.cafile
+        elif CONF.fetcher_prometheus.insecure:
+            verify = False
+
+        self._conn = PrometheusClient(
+            url,
+            auth=(user, password) if user and password else None,
+            verify=verify,
+        )
+
+    def get_tenants(self):
+        metric = CONF.fetcher_prometheus.metric
+        scope_attribute = CONF.fetcher_prometheus.scope_attribute
+        filters = CONF.fetcher_prometheus.filters
+
+        metadata = ''
+        # Preformatting filters as {label1="value1", label2="value2"}
+        if filters:
+            metadata = '{{{}}}'.format(', '.join([
+                '{}="{}"'.format(k, v) for k, v in filters.items()
+            ]))
+
+        # Formatting PromQL query
+        query = 'max({}{}) by ({})'.format(
+            metric,
+            metadata,
+            scope_attribute,
+        )
+
+        try:
+            res = self._conn.get_instant(query)
+        except PrometheusResponseError as e:
+            raise PrometheusFetcherError(*e.args)
+
+        try:
+            result = res['data']['result']
+            if not result:
+                return []
+
+            scope_ids = [
+                item['metric'][scope_attribute] for item in result
+                if item['metric'][scope_attribute]
+            ]
+        except KeyError as e:
+            missing_key = e.args[0]
+            if missing_key in ['data', 'result', 'metric']:
+                msg = (
+                    'Unexpected Prometheus server response '
+                    '"{}" for "{}"'
+                ).format(
+                    res,
+                    query,
+                )
+            else:
+                msg = '"{}" not found in Prometheus server response'.format(
+                    missing_key
+                )
+            raise PrometheusFetcherError(msg)
+
+        # Returning unique ids
+        return list(set(scope_ids))

cloudkitty/tests/collectors/test_prometheus.py

@@ -20,8 +20,9 @@ from decimal import Decimal
 import mock
 
 from cloudkitty import collector
+from cloudkitty.collector import exceptions
 from cloudkitty.collector import prometheus
-from cloudkitty import json_utils as json
+from cloudkitty.common.prometheus_client import PrometheusResponseError
 from cloudkitty import tests
 from cloudkitty.tests import samples
 from cloudkitty import transformer
@@ -150,7 +151,7 @@ class PrometheusCollectorTest(tests.TestCase):
         }
 
         no_response = mock.patch(
-            'cloudkitty.collector.prometheus.PrometheusClient.get_instant',
+            'cloudkitty.common.prometheus_client.PrometheusClient.get_instant',
             return_value=samples.PROMETHEUS_RESP_INSTANT_QUERY,
         )
 
@@ -167,7 +168,7 @@ class PrometheusCollectorTest(tests.TestCase):
 
     def test_format_retrieve_raise_NoDataCollected(self):
         no_response = mock.patch(
-            'cloudkitty.collector.prometheus.PrometheusClient.get_instant',
+            'cloudkitty.common.prometheus_client.PrometheusClient.get_instant',
             return_value=samples.PROMETHEUS_EMPTY_RESP_INSTANT_QUERY,
         )
 
@@ -182,136 +183,19 @@ class PrometheusCollectorTest(tests.TestCase):
                 q_filter=None,
             )
 
-
+    def test_format_retrieve_all_raises_exception(self):
-class PrometheusClientTest(tests.TestCase):
+        invalid_response = mock.patch(
-
+            'cloudkitty.common.prometheus_client.PrometheusClient.get_instant',
-    class FakeResponse(object):
+            side_effect=PrometheusResponseError,
-        """Mimics an HTTP ``requests`` response"""
-
-        def __init__(self, url, text, status_code):
-            self.url = url
-            self.text = text
-            self.status_code = status_code
-
-        def json(self):
-            return json.loads(self.text)
-
-    @staticmethod
-    def _mock_requests_get(text):
-        """Factory to build FakeResponse with desired response body text"""
-        return lambda *args, **kwargs: PrometheusClientTest.FakeResponse(
-            args[0], text, 200,
         )
 
-    def setUp(self):
+        with invalid_response:
-        super(PrometheusClientTest, self).setUp()
-        self.client = prometheus.PrometheusClient(
-            'http://localhost:9090/api/v1',
-        )
-
-    def test_get_with_no_options(self):
-        with mock.patch('requests.get') as mock_get:
-            self.client._get(
-                'query_range',
-                params={
-                    'query': 'max(http_requests_total) by (project_id)',
-                    'start': samples.FIRST_PERIOD_BEGIN,
-                    'end': samples.FIRST_PERIOD_END,
-                    'step': 10,
-                },
-            )
-            mock_get.assert_called_once_with(
-                'http://localhost:9090/api/v1/query_range',
-                params={
-                    'query': 'max(http_requests_total) by (project_id)',
-                    'start': samples.FIRST_PERIOD_BEGIN,
-                    'end': samples.FIRST_PERIOD_END,
-                    'step': 10,
-                },
-                auth=None,
-                verify=True,
-            )
-
-    def test_get_with_options(self):
-        client = prometheus.PrometheusClient(
-            'http://localhost:9090/api/v1',
-            auth=('foo', 'bar'),
-            verify='/some/random/path',
-        )
-        with mock.patch('requests.get') as mock_get:
-            client._get(
-                'query_range',
-                params={
-                    'query': 'max(http_requests_total) by (project_id)',
-                    'start': samples.FIRST_PERIOD_BEGIN,
-                    'end': samples.FIRST_PERIOD_END,
-                    'step': 10,
-                },
-            )
-            mock_get.assert_called_once_with(
-                'http://localhost:9090/api/v1/query_range',
-                params={
-                    'query': 'max(http_requests_total) by (project_id)',
-                    'start': samples.FIRST_PERIOD_BEGIN,
-                    'end': samples.FIRST_PERIOD_END,
-                    'step': 10,
-                },
-                auth=('foo', 'bar'),
-                verify='/some/random/path',
-            )
-
-    def test_get_instant(self):
-        mock_get = mock.patch(
-            'requests.get',
-            side_effect=self._mock_requests_get('{"foo": "bar"}'),
-        )
-
-        with mock_get:
-            res = self.client.get_instant(
-                'max(http_requests_total) by (project_id)',
-            )
-            self.assertEqual(res, {'foo': 'bar'})
-
-    def test_get_range(self):
-        mock_get = mock.patch(
-            'requests.get',
-            side_effect=self._mock_requests_get('{"foo": "bar"}'),
-        )
-
-        with mock_get:
-            res = self.client.get_range(
-                'max(http_requests_total) by (project_id)',
-                samples.FIRST_PERIOD_BEGIN,
-                samples.FIRST_PERIOD_END,
-                10,
-            )
-            self.assertEqual(res, {'foo': 'bar'})
-
-    def test_get_instant_raises_error_on_bad_json(self):
-        # Simulating malformed JSON response from HTTP+PromQL instant request
-        mock_get = mock.patch(
-            'requests.get',
-            side_effect=self._mock_requests_get('{"foo": "bar"'),
-        )
-        with mock_get:
             self.assertRaises(
-                prometheus.PrometheusResponseError,
+                exceptions.CollectError,
-                self.client.get_instant,
+                self.collector.retrieve,
-                'max(http_requests_total) by (project_id)',
+                metric_name='http_requests_total',
-            )
+                start=samples.FIRST_PERIOD_BEGIN,
-
+                end=samples.FIRST_PERIOD_END,
-    def test_get_range_raises_error_on_bad_json(self):
+                project_id=samples.TENANT,
-        # Simulating malformed JSON response from HTTP+PromQL range request
+                q_filter=None,
-        mock_get = mock.patch(
-            'requests.get',
-            side_effect=self._mock_requests_get('{"foo": "bar"'),
-        )
-        with mock_get:
-            self.assertRaises(
-                prometheus.PrometheusResponseError,
-                self.client.get_range,
-                'max(http_requests_total) by (project_id)',
-                samples.FIRST_PERIOD_BEGIN,
-                samples.FIRST_PERIOD_END,
-                10,
             )

cloudkitty/tests/common/test_prometheus_client.py

@@ -0,0 +1,155 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 Objectif Libre
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+#
+import mock
+
+from cloudkitty.collector import prometheus
+from cloudkitty import json_utils as json
+from cloudkitty import tests
+from cloudkitty.tests import samples
+
+
+class PrometheusClientTest(tests.TestCase):
+
+    class FakeResponse(object):
+        """Mimics an HTTP ``requests`` response"""
+
+        def __init__(self, url, text, status_code):
+            self.url = url
+            self.text = text
+            self.status_code = status_code
+
+        def json(self):
+            return json.loads(self.text)
+
+    @staticmethod
+    def _mock_requests_get(text):
+        """Factory to build FakeResponse with desired response body text"""
+        return lambda *args, **kwargs: PrometheusClientTest.FakeResponse(
+            args[0], text, 200,
+        )
+
+    def setUp(self):
+        super(PrometheusClientTest, self).setUp()
+        self.client = prometheus.PrometheusClient(
+            'http://localhost:9090/api/v1',
+        )
+
+    def test_get_with_no_options(self):
+        with mock.patch('requests.get') as mock_get:
+            self.client._get(
+                'query_range',
+                params={
+                    'query': 'max(http_requests_total) by (project_id)',
+                    'start': samples.FIRST_PERIOD_BEGIN,
+                    'end': samples.FIRST_PERIOD_END,
+                    'step': 10,
+                },
+            )
+            mock_get.assert_called_once_with(
+                'http://localhost:9090/api/v1/query_range',
+                params={
+                    'query': 'max(http_requests_total) by (project_id)',
+                    'start': samples.FIRST_PERIOD_BEGIN,
+                    'end': samples.FIRST_PERIOD_END,
+                    'step': 10,
+                },
+                auth=None,
+                verify=True,
+            )
+
+    def test_get_with_options(self):
+        client = prometheus.PrometheusClient(
+            'http://localhost:9090/api/v1',
+            auth=('foo', 'bar'),
+            verify='/some/random/path',
+        )
+        with mock.patch('requests.get') as mock_get:
+            client._get(
+                'query_range',
+                params={
+                    'query': 'max(http_requests_total) by (project_id)',
+                    'start': samples.FIRST_PERIOD_BEGIN,
+                    'end': samples.FIRST_PERIOD_END,
+                    'step': 10,
+                },
+            )
+            mock_get.assert_called_once_with(
+                'http://localhost:9090/api/v1/query_range',
+                params={
+                    'query': 'max(http_requests_total) by (project_id)',
+                    'start': samples.FIRST_PERIOD_BEGIN,
+                    'end': samples.FIRST_PERIOD_END,
+                    'step': 10,
+                },
+                auth=('foo', 'bar'),
+                verify='/some/random/path',
+            )
+
+    def test_get_instant(self):
+        mock_get = mock.patch(
+            'requests.get',
+            side_effect=self._mock_requests_get('{"foo": "bar"}'),
+        )
+
+        with mock_get:
+            res = self.client.get_instant(
+                'max(http_requests_total) by (project_id)',
+            )
+            self.assertEqual(res, {'foo': 'bar'})
+
+    def test_get_range(self):
+        mock_get = mock.patch(
+            'requests.get',
+            side_effect=self._mock_requests_get('{"foo": "bar"}'),
+        )
+
+        with mock_get:
+            res = self.client.get_range(
+                'max(http_requests_total) by (project_id)',
+                samples.FIRST_PERIOD_BEGIN,
+                samples.FIRST_PERIOD_END,
+                10,
+            )
+            self.assertEqual(res, {'foo': 'bar'})
+
+    def test_get_instant_raises_error_on_bad_json(self):
+        # Simulating malformed JSON response from HTTP+PromQL instant request
+        mock_get = mock.patch(
+            'requests.get',
+            side_effect=self._mock_requests_get('{"foo": "bar"'),
+        )
+        with mock_get:
+            self.assertRaises(
+                prometheus.PrometheusResponseError,
+                self.client.get_instant,
+                'max(http_requests_total) by (project_id)',
+            )
+
+    def test_get_range_raises_error_on_bad_json(self):
+        # Simulating malformed JSON response from HTTP+PromQL range request
+        mock_get = mock.patch(
+            'requests.get',
+            side_effect=self._mock_requests_get('{"foo": "bar"'),
+        )
+        with mock_get:
+            self.assertRaises(
+                prometheus.PrometheusResponseError,
+                self.client.get_range,
+                'max(http_requests_total) by (project_id)',
+                samples.FIRST_PERIOD_BEGIN,
+                samples.FIRST_PERIOD_END,
+                10,
+            )

cloudkitty/tests/fetchers/test_prometheus.py

@@ -0,0 +1,105 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 Objectif Libre
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+#
+#
+import mock
+
+from cloudkitty.common.prometheus_client import PrometheusClient
+from cloudkitty.common.prometheus_client import PrometheusResponseError
+from cloudkitty.fetcher import prometheus
+from cloudkitty import tests
+
+
+class PrometheusFetcherTest(tests.TestCase):
+    def setUp(self):
+        super(PrometheusFetcherTest, self).setUp()
+        self.conf.set_override(
+            'metric', 'http_requests_total', 'fetcher_prometheus',
+        )
+        self.conf.set_override(
+            'scope_attribute', 'namespace', 'fetcher_prometheus',
+        )
+        self.fetcher = prometheus.PrometheusFetcher()
+
+    def test_get_tenants_build_query(self):
+        query = (
+            'max(http_requests_total) by (namespace)'
+        )
+
+        with mock.patch.object(
+            PrometheusClient, 'get_instant',
+        ) as mock_get:
+            self.fetcher.get_tenants()
+            mock_get.assert_called_once_with(query)
+
+    def test_get_tenants_build_query_with_filter(self):
+        query = (
+            'max(http_requests_total{label1="foo"})'
+            ' by (namespace)'
+        )
+
+        self.conf.set_override(
+            'filters', 'label1:foo', 'fetcher_prometheus',
+        )
+
+        with mock.patch.object(
+            PrometheusClient, 'get_instant',
+        ) as mock_get:
+            self.fetcher.get_tenants()
+            mock_get.assert_called_once_with(query)
+
+    def test_get_tenants_raises_exception(self):
+        no_response = mock.patch(
+            'cloudkitty.common.prometheus_client.PrometheusClient.get_instant',
+            return_value={},
+        )
+
+        with no_response:
+            self.assertRaises(
+                prometheus.PrometheusFetcherError,
+                self.fetcher.get_tenants,
+            )
+
+    def test_get_tenants_raises_exception2(self):
+        no_response = mock.patch(
+            'cloudkitty.common.prometheus_client.PrometheusClient.get_instant',
+            return_value={
+                'data': {
+                    'result': [{
+                        'metric': {
+                            'foo': 'bar'
+                        }
+                    }]
+                }
+            },
+        )
+
+        with no_response:
+            self.assertRaises(
+                prometheus.PrometheusFetcherError,
+                self.fetcher.get_tenants,
+            )
+
+    def test_get_tenants_raises_exception3(self):
+        invalid_response = mock.patch(
+            'cloudkitty.common.prometheus_client.PrometheusClient.get_instant',
+            side_effect=PrometheusResponseError,
+        )
+
+        with invalid_response:
+            self.assertRaises(
+                prometheus.PrometheusFetcherError,
+                self.fetcher.get_tenants,
+            )

releasenotes/notes/add-prometheus-fetcher-be6082f70f279f0e.yaml

@@ -0,0 +1,10 @@
+---
+features:
+  - |
+    A Prometheus scope fetcher has been added in order to dynamically discover
+    scopes from a Prometheus service using a user defined metric and a scope
+    attribute.
+    It can also filter out the response from Prometheus using metadata filters
+    to have a more fine-grained control over scope discovery.
+    It features HTTP basic auth capabilities and HTTPS configuration options
+    similar to Prometheus collector.

setup.cfg

@@ -54,6 +54,7 @@ cloudkitty.fetchers =
     keystone = cloudkitty.fetcher.keystone:KeystoneFetcher
     source = cloudkitty.fetcher.source:SourceFetcher
     gnocchi = cloudkitty.fetcher.gnocchi:GnocchiFetcher
+    prometheus = cloudkitty.fetcher.prometheus:PrometheusFetcher
 
 cloudkitty.transformers =
     CloudKittyFormatTransformer = cloudkitty.transformer.format:CloudKittyFormatTransformer