match archive policy rule based on longest match

currently, we use the first archive policy rule that we match based
on querying the existing rules. this list of rules is unordered.
this patch explicitly orders rules by metric_pattern so match against
the longest match first.

Change-Id: I4cc99ccbf98c1920d46ae259c81275953e9bfb03
Co-Authored-By: Alejandro Comisario <alejandro@nubeliu.com>
Closes-bug: #1501344

doc/source/rest.j2

@@ -152,13 +152,16 @@ match metric names.
 An archive policy rule for example could be a mapping to default a medium archive
 policy for any volume metric with a pattern matching `volume.*`. When a sample metric
 is posted with a name of `volume.size`, that would match the pattern and the
-rule applies and sets the archive policy to medium.
+rule applies and sets the archive policy to medium. If multiple rules match,
+the longest matching rule is taken. For example, if two rules exists which
+match `*` and `disk.*`, a `disk.io.rate` metric would match the `disk.*` rule
+rather than `*` rule.
 
 To create a rule, the following API request should be used:
 
 {{ scenarios['create-archive-policy-rule']['doc'] }}
 
-The metric_pattern is used to pattern match so as some examples,
+The `metric_pattern` is used to pattern match so as some examples,
 
 - `*` matches anything
 - `disk.*` matches disk.io
@@ -168,7 +171,8 @@ Once created, you can retrieve the rule information:
 
 {{ scenarios['get-archive-policy-rule']['doc'] }}
 
-It is also possible to list archive policy rules:
+It is also possible to list archive policy rules. The result set is ordered by
+the `metric_pattern`, in reverse alphabetical order:
 
 {{ scenarios['list-archive-policy-rule']['doc'] }}
 

gnocchi/indexer/sqlalchemy.py

@@ -165,7 +165,8 @@ class SQLAlchemyIndexer(indexer.IndexerDriver):
 
     def list_archive_policy_rules(self):
         session = self.engine_facade.get_session()
-        aps = session.query(ArchivePolicyRule).all()
+        aps = session.query(ArchivePolicyRule).order_by(
+            ArchivePolicyRule.metric_pattern.desc()).all()
         session.expunge_all()
         return aps
 

gnocchi/tests/gabbi/gabbits/archive_rule.yaml

@@ -25,21 +25,54 @@ tests:
 
 # Attempt to create an archive policy rule
 
-    - name: create archive policy rule
+    - name: create archive policy rule1
       url: /v1/archive_policy_rule
       method: POST
       request_headers:
           content-type: application/json
           x-roles: admin
       data:
-        name: test_rule
+        name: test_rule1
+        metric_pattern: "*"
+        archive_policy_name: low
+      status: 201
+      response_json_paths:
+        $.metric_pattern: "*"
+        $.archive_policy_name: low
+        $.name: test_rule1
+
+    - name: create archive policy rule 2
+      url: /v1/archive_policy_rule
+      method: POST
+      request_headers:
+          content-type: application/json
+          x-roles: admin
+      data:
+        name: test_rule2
         metric_pattern: "disk.foo.*"
         archive_policy_name: low
       status: 201
       response_json_paths:
         $.metric_pattern: disk.foo.*
         $.archive_policy_name: low
-        $.name: test_rule
+        $.name: test_rule2
+
+    - name: create archive policy rule 3
+      url: /v1/archive_policy_rule
+      method: POST
+      request_headers:
+          content-type: application/json
+          x-roles: admin
+      data:
+        name: test_rule3
+        metric_pattern: "disk.*"
+        archive_policy_name: low
+      status: 201
+      response_json_paths:
+        $.metric_pattern: disk.*
+        $.archive_policy_name: low
+        $.name: test_rule3
+
 
 # Attempt to create an invalid policy rule
 
@@ -115,6 +148,10 @@ tests:
     - name: get archive policy rule
       url: /v1/archive_policy_rule
       status: 200
+      response_json_paths:
+        $.[0].metric_pattern: disk.foo.*
+        $.[1].metric_pattern: disk.*
+        $.[2].metric_pattern: "*"
 
     - name: get unknown archive policy rule
       url: /v1/archive_policy_rule/foo
@@ -123,14 +160,29 @@ tests:
 # delete rule as non admin
 
     - name: delete archive policy rule non admin
-      url: /v1/archive_policy_rule/test_rule
+      url: /v1/archive_policy_rule/test_rule1
       method: DELETE
       status: 403
 
 # delete rule
 
-    - name: delete archive policy rule
-      url: /v1/archive_policy_rule/test_rule
+    - name: delete archive policy rule1
+      url: /v1/archive_policy_rule/test_rule1
+      method: DELETE
+      request_headers:
+          x-roles: admin
+      status: 204
+
+    - name: delete archive policy rule2
+      url: /v1/archive_policy_rule/test_rule2
+      method: DELETE
+      request_headers:
+          x-roles: admin
+      status: 204
+
+
+    - name: delete archive policy rule3
+      url: /v1/archive_policy_rule/test_rule3
       method: DELETE
       request_headers:
           x-roles: admin
@@ -139,7 +191,7 @@ tests:
 # delete again
 
     - name: confirm delete archive policy rule
-      url: /v1/archive_policy_rule/test_rule
+      url: /v1/archive_policy_rule/test_rule1
       method: DELETE
       request_headers:
         x-roles: admin

gnocchi/tests/gabbi/gabbits/metric.yaml

@@ -32,6 +32,31 @@ tests:
         archive_policy_name: cookies
       status: 201
 
+    - name: create alt archive policy
+      url: /v1/archive_policy
+      method: POST
+      request_headers:
+          content-type: application/json
+          x-roles: admin
+      data:
+          name: cream
+          definition:
+              - granularity: 5 second
+      status: 201
+
+    - name: create alt archive policy rule
+      desc: extra rule that won't be matched
+      url: /v1/archive_policy_rule
+      method: POST
+      request_headers:
+          content-type: application/json
+          x-roles: admin
+      data:
+        name: test_ignore_rule
+        metric_pattern: "disk.*"
+        archive_policy_name: cream
+      status: 201
+
     - name: get metric empty
       url: /v1/metric
       status: 200
@@ -176,4 +201,4 @@ tests:
     - name: delete non existent metric
       url: /v1/metric/foo
       method: DELETE
-      status: 404
+      status: 404

gnocchi/tests/test_indexer.py

@@ -69,6 +69,19 @@ class TestIndexerDriver(tests_base.TestCase):
                           "low")
         self.index.delete_metric(metric_id)
 
+    def test_list_ap_rules_ordered(self):
+        name = str(uuid.uuid4())
+        self.index.create_archive_policy(
+            archive_policy.ArchivePolicy(name, 0, {}))
+        self.index.create_archive_policy_rule('rule1', 'abc.*', name)
+        self.index.create_archive_policy_rule('rule2', 'abc.xyz.*', name)
+        self.index.create_archive_policy_rule('rule3', 'abc.xyz', name)
+        rules = self.index.list_archive_policy_rules()
+        self.assertEqual(3, len(rules))
+        self.assertEqual('abc.xyz.*', rules[0]['metric_pattern'])
+        self.assertEqual('abc.xyz', rules[1]['metric_pattern'])
+        self.assertEqual('abc.*', rules[2]['metric_pattern'])
+
     def test_create_metric(self):
         r1 = uuid.uuid4()
         user = uuid.uuid4()