apply limit constraint on storage base interface

Currently we have implemented limit constraint on get_meters,
get_resources, get_samples and query_samples on most of major databases,
but haven't applied such change on storage interface of get_meters and
get_resources, this patch adds parameter limit to those two methods.

Change-Id: I10e43e082ec9fd87dcd491299a57c0116009220e
Closes-Bug: #1496677

ceilometer/api/controllers/v2/meters.py

@@ -491,11 +491,8 @@ class MetersController(rest.RestController):
         # Timestamp field is not supported for Meter queries
         limit = v2_utils.enforce_limit(limit)
         kwargs = v2_utils.query_to_kwargs(
-            q, pecan.request.storage_conn.get_meters, allow_timestamps=False)
-        if 'limit' in kwargs:
-            raise base.ClientSideError(_(
-                "Limit is not a valid field for queries, "
-                "use 'limit' parameter."))
+            q, pecan.request.storage_conn.get_meters,
+            ['limit'], allow_timestamps=False)
         return [Meter.from_db_model(m)
                 for m in pecan.request.storage_conn.get_meters(limit=limit,
                                                                **kwargs)]

ceilometer/api/controllers/v2/resources.py

@@ -142,11 +142,7 @@ class ResourcesController(rest.RestController):
         q = q or []
         limit = utils.enforce_limit(limit)
         kwargs = utils.query_to_kwargs(
-            q, pecan.request.storage_conn.get_resources)
-        if 'limit' in kwargs:
-            raise base.ClientSideError(_(
-                "Limit is not a valid field for queries, "
-                "use 'limit' parameter."))
+            q, pecan.request.storage_conn.get_resources, ['limit'])
         resources = [
             Resource.from_db_and_links(r,
                                        self._resource_links(r.resource_id,

ceilometer/storage/base.py

@@ -176,7 +176,7 @@ class Connection(object):
     def get_resources(user=None, project=None, source=None,
                       start_timestamp=None, start_timestamp_op=None,
                       end_timestamp=None, end_timestamp_op=None,
-                      metaquery=None, resource=None):
+                      metaquery=None, resource=None, limit=None):
         """Return an iterable of models.Resource instances.
 
         Iterable items containing resource information.
@@ -189,12 +189,13 @@ class Connection(object):
         :param end_timestamp_op: Optional timestamp end range operation.
         :param metaquery: Optional dict with metadata to match on.
         :param resource: Optional resource filter.
+        :param limit: Maximum number of results to return.
         """
         raise ceilometer.NotImplementedError('Resources not implemented')
 
     @staticmethod
     def get_meters(user=None, project=None, resource=None, source=None,
-                   metaquery=None):
+                   metaquery=None, limit=None):
         """Return an iterable of model.Meter instances.
 
         Iterable items containing meter information.
@@ -203,6 +204,7 @@ class Connection(object):
         :param resource: Optional resource filter.
         :param source: Optional source filter.
         :param metaquery: Optional dict with metadata to match on.
+        :param limit: Maximum number of results to return.
         """
         raise ceilometer.NotImplementedError('Meters not implemented')
 

ceilometer/storage/impl_log.py

@@ -55,7 +55,7 @@ class Connection(base.Connection):
     def get_resources(self, user=None, project=None, source=None,
                       start_timestamp=None, start_timestamp_op=None,
                       end_timestamp=None, end_timestamp_op=None,
-                      metaquery=None, resource=None):
+                      metaquery=None, resource=None, limit=None):
         """Return an iterable of dictionaries containing resource information.
 
         { 'resource_id': UUID of the resource,
@@ -75,6 +75,7 @@ class Connection(base.Connection):
         :param end_timestamp_op: Optional end time operator, like lt, le.
         :param metaquery: Optional dict with metadata to match on.
         :param resource: Optional resource filter.
+        :param limit: Maximum number of results to return.
         """
         return []
 
@@ -98,7 +99,7 @@ class Connection(base.Connection):
         """
         return []
 
-    def get_samples(self, sample_filter):
+    def get_samples(self, sample_filter, limit=None):
         """Return an iterable of samples.
 
         Items are created by

ceilometer/tests/functional/gabbi/gabbits/meters.yaml

@@ -374,10 +374,10 @@ tests:
       url: /v2/meters?q.field=limit&q.op=eq&q.type=&q.value=1
       status: 400
       response_strings:
-          - Limit is not a valid field for queries,
+          - 'Unknown argument: \"limit\": unrecognized field in query'
 
     - name: get meters filter limit and limit
       url: /v2/meters?q.field=limit&q.op=eq&q.type=&q.value=1&limit=1
       status: 400
       response_strings:
-          - Limit is not a valid field for queries,
+          - 'Unknown argument: \"limit\": unrecognized field in query'

ceilometer/tests/functional/gabbi/gabbits/resources-fixtured.yaml

@@ -77,10 +77,10 @@ tests:
       url: /v2/resources?q.field=limit&q.op=eq&q.type=&q.value=1
       status: 400
       response_strings:
-          - Limit is not a valid field for queries,
+          - 'Unknown argument: \"limit\": unrecognized field in query'
 
     - name: get resources filter limit and limit
       url: /v2/resources?q.field=limit&q.op=eq&q.type=&q.value=1&limit=1
       status: 400
       response_strings:
-          - Limit is not a valid field for queries,
+          - 'Unknown argument: \"limit\": unrecognized field in query'

ceilometer/tests/unit/api/v2/test_query.py

@@ -380,7 +380,8 @@ class TestQueryToKwArgs(tests_base.BaseTestCase):
                            value='abc')]
         exc = self.assertRaises(
             wsme.exc.UnknownArgument,
-            utils.query_to_kwargs, q, storage_base.Connection.get_meters)
+            utils.query_to_kwargs,
+            q, storage_base.Connection.get_meters, ['limit'])
         valid_keys = ['project', 'resource', 'source', 'user']
         msg = ("unrecognized field in query: %s, "
                "valid keys: %s") % (q, valid_keys)
@@ -393,7 +394,8 @@ class TestQueryToKwArgs(tests_base.BaseTestCase):
                            value='abc')]
         exc = self.assertRaises(
             wsme.exc.UnknownArgument,
-            utils.query_to_kwargs, q, storage_base.Connection.get_resources)
+            utils.query_to_kwargs,
+            q, storage_base.Connection.get_resources, ['limit'])
         valid_keys = ['project', 'resource',
                       'search_offset', 'source', 'timestamp', 'user']
         msg = ("unrecognized field in query: %s, "