Fix return error when resource can't be found

By current implement, the HTTP request for /v2/resources/<resource_id>
will return 500 if there is no coresponding resource or the resource id
is invalid. And the response is as below:

{"error_message": "{"debuginfo": null, "faultcode": "Server",
"faultstring": "list index out of range"}"}

After fixed, the response will be like this:

{"error_message": "{"debuginfo": null, "faultcode": "Client",
"faultstring": "Invalid input for field/attribute resource_id.
Value: '9'. Unknown resource"}"}

Fixes bug: 1195925

Change-Id: I73c73fb3ba57bc6cbbf421f9ac5ec3cdb68ce784
(cherry picked from commit fbb1eb9285c7787f8508d3f69790522ff6847fc8)

2 files changed, 57 insertions, 3 deletions

diff --git a/ceilometer/api/controllers/v2.py b/ceilometer/api/controllers/v2.py
index 0129ea63..c58241ee 100644
--- a/ceilometer/api/controllers/v2.py
+++ b/ceilometer/api/controllers/v2.py
@@ -501,9 +501,13 @@ class ResourcesController(rest.RestController):
 
         :param resource_id: The UUID of the resource.
         """
-        r = list(pecan.request.storage_conn.get_resources(
-                 resource=resource_id))[0]
-        return Resource(**r)
+        resources = list(pecan.request.storage_conn.get_resources(
+                         resource=resource_id))
+        if not resources:
+            raise wsme.exc.InvalidInput("resource_id",
+                                        resource_id,
+                                        _("Unknown resource"))
+        return Resource(**resources[0])
 
     @wsme_pecan.wsexpose([Resource], [Query])
     def get_all(self, q=[]):
diff --git a/tests/api/v2/test_list_resources.py b/tests/api/v2/test_list_resources.py
index ab9c1359..88337baf 100644
--- a/tests/api/v2/test_list_resources.py
+++ b/tests/api/v2/test_list_resources.py
@@ -189,6 +189,56 @@ class TestListResources(FunctionalTest):
         ids = [r['resource_id'] for r in data]
         self.assertEquals(['resource-id'], ids)
 
+    def test_with_invalid_resource_id(self):
+        counter1 = counter.Counter(
+            'instance',
+            'cumulative',
+            '',
+            1,
+            'user-id',
+            'project-id',
+            'resource-id-1',
+            timestamp=datetime.datetime(2012, 7, 2, 10, 40),
+            resource_metadata={'display_name': 'test-server',
+                               'tag': 'self.counter',
+                               }
+        )
+        msg = rpc.meter_message_from_counter(
+            counter1,
+            cfg.CONF.publisher_rpc.metering_secret,
+            'test_list_resources',
+        )
+        self.conn.record_metering_data(msg)
+
+        counter2 = counter.Counter(
+            'instance',
+            'cumulative',
+            '',
+            1,
+            'user-id2',
+            'project-id',
+            'resource-id-2',
+            timestamp=datetime.datetime(2012, 7, 2, 10, 41),
+            resource_metadata={'display_name': 'test-server',
+                               'tag': 'self.counter2',
+                               }
+        )
+        msg2 = rpc.meter_message_from_counter(
+            counter2,
+            cfg.CONF.publisher_rpc.metering_secret,
+            'test_list_resources',
+        )
+        self.conn.record_metering_data(msg2)
+
+        resp1 = self.get_json('/resources/resource-id-1')
+        self.assertEquals(resp1["resource_id"], "resource-id-1")
+
+        resp2 = self.get_json('/resources/resource-id-2')
+        self.assertEquals(resp2["resource_id"], "resource-id-2")
+
+        resp3 = self.get_json('/resources/resource-id-3', expect_errors=True)
+        self.assertEquals(resp3.status_code, 400)
+
     def test_with_user(self):
         counter1 = counter.Counter(
             'instance',