Add new version of OpenMetrics base class

datadog_checks_base/datadog_checks/base/checks/openmetrics/base_check.py

@@ -7,6 +7,9 @@
 from .. import AgentCheck
 from .mixins import OpenMetricsScraperMixin
 
+if not PY2:
+    from .v2.base import OpenMetricsBaseCheckV2
+
 STANDARD_FIELDS = [
     'prometheus_url',
     'namespace',
@@ -60,6 +63,17 @@ class OpenMetricsBaseCheck(OpenMetricsScraperMixin, AgentCheck):
         'prometheus_timeout': {'name': 'timeout'},
     }
 
+    def __new__(cls, *args, **kwargs):
+        # Legacy signature
+        if len(args) != 3:
+            return super(OpenMetricsBaseCheck, cls).__new__(cls)
+
+        instance = args[2][0]
+        if not PY2 and 'prometheus_endpoints' in instance:
+            return OpenMetricsBaseCheckV2(*args, **kwargs)
+        else:
+            return super(OpenMetricsBaseCheck, cls).__new__(cls)
+
     def __init__(self, *args, **kwargs):
         """
         The base class for any Prometheus-based integration.

datadog_checks_base/datadog_checks/base/checks/openmetrics/mixins.py

@@ -62,6 +62,8 @@ def create_scraper_configuration(self, instance=None):
 
         A default mixin configuration will be returned if there is no instance.
         """
+        if 'prometheus_endpoints' in instance:
+            raise CheckException('The setting `prometheus_endpoints` is only available for Agent version 7 or later')
 
         # We can choose to create a default mixin configuration for an empty instance
         if instance is None:

datadog_checks_base/datadog_checks/base/checks/openmetrics/v2/__init__.py

@@ -0,0 +1,3 @@
+# (C) Datadog, Inc. 2020-present
+# All rights reserved
+# Licensed under a 3-clause BSD style license (see LICENSE)

datadog_checks_base/datadog_checks/base/checks/openmetrics/v2/base.py

@@ -0,0 +1,81 @@
+# (C) Datadog, Inc. 2020-present
+# All rights reserved
+# Licensed under a 3-clause BSD style license (see LICENSE)
+from collections import OrderedDict
+from contextlib import contextmanager
+
+from ....errors import ConfigurationError
+from ... import AgentCheck
+from .scraper import OpenMetricsScraper
+
+try:
+    from collections import ChainMap
+except ImportError:
+    from chainmap import ChainMap
+
+
+class OpenMetricsBaseCheckV2(AgentCheck):
+    DEFAULT_METRIC_LIMIT = 2000
+
+    def __init__(self, name, init_config, instances):
+        super(OpenMetricsBaseCheckV2, self).__init__(name, init_config, instances)
+
+        # All desired scraper configurations, which subclasses can override as needed
+        self.scraper_configs = [self.instance]
+
+        # All configured scrapers keyed by the endpoint
+        self.scrapers = OrderedDict()
+
+        self.check_initializations.append(self.configure_scrapers)
+
+    def check(self, _):
+        for endpoint, scraper in self.scrapers.items():
+            self.log.info('Scraping Prometheus endpoint: %s', endpoint)
+
+            with self.adopt_namespace(scraper.namespace):
+                scraper.scrape()
+
+    def configure_scrapers(self):
+        scrapers = OrderedDict()
+
+        for config in self.scraper_configs:
+            endpoints = config.get('prometheus_endpoints', [])
+            if not isinstance(endpoints, list):
+                raise ConfigurationError('Setting `prometheus_endpoints` must be an array')
+            elif not endpoints:
+                raise ConfigurationError('Setting `prometheus_endpoints` is required')
+
+            for i, endpoint in enumerate(endpoints, 1):
+                if not isinstance(endpoint, str):
+                    raise ConfigurationError(
+                        'Endpoint #{} of setting `prometheus_endpoints` must be a string'.format(i)
+                    )
+                elif not endpoint:
+                    raise ConfigurationError(
+                        'Endpoint #{} of setting `prometheus_endpoints` must not be an empty string'.format(i)
+                    )
+
+                scrapers[endpoint] = self.create_scraper(endpoint, config)
+
+        self.scrapers.clear()
+        self.scrapers.update(scrapers)
+
+    def create_scraper(self, endpoint, config):
+        # Subclasses can override to return a custom scraper based on configuration
+        return OpenMetricsScraper(self, endpoint, self.get_config_with_defaults(config))
+
+    def get_config_with_defaults(self, config):
+        return ChainMap(config, self.get_default_config())
+
+    def get_default_config(self):
+        return {}
+
+    @contextmanager
+    def adopt_namespace(self, namespace):
+        old_namespace = self.__NAMESPACE__
+
+        try:
+            self.__NAMESPACE__ = namespace or old_namespace
+            yield
+        finally:
+            self.__NAMESPACE__ = old_namespace