Implements an API endpoint for retrieving generated alert IDs, tests and documentation included

docs/clmc-service.md

@@ -39,6 +39,41 @@ configuration files of the service can be found in the **src/service** folder.
 
 ## Alerts API Endpoints
 
+* **GET** ***/alerts?sfc={service function chain id}&sfci={service function chain instance id}&policy={policy id}&trigger={trigger id}***
+
+    This API method can be used to retrieve the generated alert task and alert topic identifiers during the processing of an alerts specification document.
+    These identifiers can then be used to interact with the Kapacitor HTTP API for further configiuration or modification of alerts - https://docs.influxdata.com/kapacitor/v1.4/working/api/.
+
+    * Request:
+    
+        Expects a URL query string with the request parameters - **sfc**, **sfci**, **policy** and **trigger**. The given parameters must match the values used in the alerts specification
+        document. Otherwise, a wrong ID will be returned.
+        
+    * Request URL Examples:
+    
+        **/alerts?sfc=MSDemo&sfci=MSDemo-premium&policy=requests_diff&trigger=low_requests**
+        
+        **/alerts?sfc=SimpleMediaService&sfci=SimpleMediaService-1&policy=rtt_deviation&trigger=increase_in_rtt**
+     
+    * Response
+    
+        The response of this request is a JSON-formatted content, which contains the task and topic identifiers, along with the Kapacitor
+        API endpoints to use for configuring the given task, topic and the respective handlers.
+        
+        Returns a 400 Bad Request if the URL query string parameters are invalid or otherwise incorrect.
+        
+    * Response Body Example:
+    
+        ```json
+        {
+            "task_identifier": "094f23d6e948c78e9fa215528973fb3aeefa5525898626c9ea049dc8e87a7388",
+            "topic_identifier": "094f23d6e948c78e9fa215528973fb3aeefa5525898626c9ea049dc8e87a7388",
+            "task_api_endpoint": "/kapacitor/v1/tasks/094f23d6e948c78e9fa215528973fb3aeefa5525898626c9ea049dc8e87a7388",
+            "topic_api_endpoint": "/kapacitor/v1/alerts/topics/094f23d6e948c78e9fa215528973fb3aeefa5525898626c9ea049dc8e87a7388",
+            "topic_handlers_api_endpoint": "/kapacitor/v1/alerts/topics/094f23d6e948c78e9fa215528973fb3aeefa5525898626c9ea049dc8e87a7388/handlers"
+        }
+        ```
+
 * **POST** ***/alerts***
 
     This API method can be used to send an alert specification document, which is then used by the CLMC service to create

src/service/clmcservice/alertsapi/tests.py

@@ -69,6 +69,32 @@ class TestAlertsConfigurationAPI(object):
 
         testing.tearDown()
 
+    @pytest.mark.parametrize("sfc_id, sfci_id, policy_id, trigger_id, task_id, topic_id", [
+        ("MSDemo", "MSDemo-premium", "requests_diff", "low_requests", "094f23d6e948c78e9fa215528973fb3aeefa5525898626c9ea049dc8e87a7388", "094f23d6e948c78e9fa215528973fb3aeefa5525898626c9ea049dc8e87a7388"),
+        ("sfc", "sfc_1", "missing_measurements", "no_latency_measurements", "1019ab70402a98905ff9e950c36d3c13a8468db8f7b8196f4ee69d6c39947fe5", "1019ab70402a98905ff9e950c36d3c13a8468db8f7b8196f4ee69d6c39947fe5"),
+        ("disney.sfc.flame.eu", "disney.sfc.flame.eu-premium", "rtt_deviation", "increase_in_rtt", "8b069cc10571f887ff6c3a14aea11e68e664ddde5bc6af08d88058865510af93", "8b069cc10571f887ff6c3a14aea11e68e664ddde5bc6af08d88058865510af93"),
+        ("vrt/novel/sfc", "vrt/novel/sfc-prototype", "deadmen_measurement", "missing_storage_measurements", "8c1aba1c61c184809d648e4ab323b9b48606847bb2e3d54bfbdf34d8a7db91d1", "8c1aba1c61c184809d648e4ab323b9b48606847bb2e3d54bfbdf34d8a7db91d1"),
+        ("vrt/novel/sfc", "vrt/novel/sfc-deployment", "deadmen_measurement", "missing_storage_measurements", "a61dbe20cbef19be384982b51e22d83f23c4e10aeede172ef8646c515b836f7b", "a61dbe20cbef19be384982b51e22d83f23c4e10aeede172ef8646c515b836f7b")
+    ])
+    def test_alerts_hash_getter(self, sfc_id, sfci_id, policy_id, trigger_id, task_id, topic_id):
+        """
+        Tests the GET method for retrieving the task and topic ID given the sfc, sfc instance, policy id and trigger id.
+        """
+
+        request = testing.DummyRequest()
+        request.params["sfc"] = sfc_id
+        request.params["sfci"] = sfci_id
+        request.params["policy"] = policy_id
+        request.params["trigger"] = trigger_id
+
+        response = AlertsConfigurationAPI(request).get_alerts_hash()
+
+        assert response["task_identifier"] == task_id, "Incorrect task identifier returned"
+        assert response["task_api_endpoint"] == "/kapacitor/v1/tasks/{0}".format(task_id), "Incorrect task API endpoint returned."
+        assert response["topic_identifier"] == topic_id, "Incorrect topic identifier returned"
+        assert response["topic_api_endpoint"] == "/kapacitor/v1/alerts/topics/{0}".format(topic_id), "Incorrect topic API endpoint returned"
+        assert response["topic_handlers_api_endpoint"] == "/kapacitor/v1/alerts/topics/{0}/handlers".format(topic_id), "Incorrect topic handlers API endpoint returned"
+
     def test_alerts_config_tosca_parsing(self):
         """
         Tests that what we consider a valid/invalid alerts specification is successfully/unsuccessfully parsed by the TOSCA-parser.

src/service/clmcservice/alertsapi/views.py

@@ -57,6 +57,31 @@ class AlertsConfigurationAPI(object):
 
         self.request = request
 
+    @view_config(route_name='alerts_configuration', request_method='GET')
+    def get_alerts_hash(self):
+
+        for param in ("sfc", "sfci", "policy", "trigger"):
+            if param not in self.request.params:
+                raise HTTPBadRequest("Missing url query string parameter {0}.".format(param))
+
+        sfc = self.request.params["sfc"]
+        sfci = self.request.params["sfci"]
+        policy = self.request.params["policy"]
+        trigger = self.request.params["trigger"]
+
+        # generate topic and alert identifiers
+        topic_id = "{0}\n{1}\n{2}\n{3}".format(sfc, sfci, policy, trigger)
+        topic_id = self.get_hash(topic_id)
+        alert_id = topic_id
+
+        return {
+            "task_identifier": alert_id,
+            "task_api_endpoint": "/kapacitor/v1/tasks/{0}".format(alert_id),
+            "topic_identifier": topic_id,
+            "topic_api_endpoint": "/kapacitor/v1/alerts/topics/{0}".format(topic_id),
+            "topic_handlers_api_endpoint": "/kapacitor/v1/alerts/topics/{0}/handlers".format(topic_id)
+        }
+
     @view_config(route_name='alerts_configuration', request_method='POST')
     def post_alerts_specification(self):
         """