From 320d642db171d7c463700de0e8445164ed16e5bf Mon Sep 17 00:00:00 2001
From: Nikolay Stanchev <ns17@it-innovation.soton.ac.uk>
Date: Tue, 16 Apr 2019 12:46:32 +0100
Subject: [PATCH] Adds a GET status API endpoint for a graph monitoring
pipeline script
---
docs/clmc-service.md | 24 ++++++++-
src/service/clmcservice/graphapi/tests.py | 60 +++++++++++++++++++----
src/service/clmcservice/graphapi/views.py | 45 ++++++++++++++---
src/service/setup.py | 1 +
4 files changed, 112 insertions(+), 18 deletions(-)
diff --git a/docs/clmc-service.md b/docs/clmc-service.md
index 7a435b7..bd6d537 100644
--- a/docs/clmc-service.md
+++ b/docs/clmc-service.md
@@ -339,8 +339,8 @@ with **/clmc-service** so that the nginx reverse proxy server (listening on port
* **DELETE** ***/graph/monitor/{request_id}***
- This API methods instructs the CLMC service to stop running a graph monitoring pipeline script associated with the request identifier in the URL.
- (retrieved from the response of a POST request for /graph/monitor), e.g. request sent to */graph/monitor/75df6f8d-3829-4fd8-a3e6-b3e917010141*
+ This API method instructs the CLMC service to stop running a graph monitoring pipeline script associated with the request identifier in the URL.
+ (could be retrieved from the response of a POST request for /graph/monitor), e.g. request sent to */graph/monitor/75df6f8d-3829-4fd8-a3e6-b3e917010141*
* Response:
@@ -356,6 +356,26 @@ with **/clmc-service** so that the nginx reverse proxy server (listening on port
}
```
+* **GET** ***/graph/monitor/{request_id}***
+
+ This API method fetches the status of a graph monitoring pipeline script associated with the request identifier in the URL.
+ (could be retrieved from the response of a POST request for /graph/monitor), e.g. request sent to */graph/monitor/75df6f8d-3829-4fd8-a3e6-b3e917010141*
+
+ * Response:
+
+ The response of this request is a JSON content, which contains a single output message along with the status of the monitoring pipeline.
+
+ Returns a 404 Not Found error if the request ID is not associated with any graph monitoring process.
+
+ * Response Body Example:
+
+ ```json
+ {
+ "status": "sleeping",
+ "msg": "Successfully fetched status of graph pipeline process."
+ }
+ ```
+
* **POST** ***/graph/temporal***
This API method sends a request to the CLMC service to build a graph snapshot in the time range between the *from* and *to* timestamps.
diff --git a/src/service/clmcservice/graphapi/tests.py b/src/service/clmcservice/graphapi/tests.py
index 4a8bd58..871dd5e 100644
--- a/src/service/clmcservice/graphapi/tests.py
+++ b/src/service/clmcservice/graphapi/tests.py
@@ -23,7 +23,7 @@
"""
from json import dumps, loads
-from signal import SIGKILL
+from psutil import NoSuchProcess, STATUS_SLEEPING
from unittest.mock import patch, Mock, MagicMock, PropertyMock
import pytest
from pyramid import testing
@@ -770,12 +770,52 @@ class TestGraphAPI(object):
assert len(popen_mock.call_args_list) == 2, "No subprocess should be started if the UE nodes list is empty (network topology not built)"
nodes_matcher_mock.assert_called_with("UserEquipment") # assert that the graph nodes match function has been called with "UserEquipment" as argument
- @patch('clmcservice.graphapi.views.kill')
- def test_stop_graph_pipeline(self, mock_kill):
+ @patch('clmcservice.graphapi.views.Process')
+ def test_get_graph_pipeline_status(self, mock_process):
"""
- Tests the funcitonality to stop a graph monitoring script.
+ Tests the functionality to fetch the status of a graph monitoring script.
- :param mock_kill: mock object to mimic the behavior of the os.kill functionality
+ :param mock_process: mock object to mimic the behavior of the psutil.Process functionality
+ """
+
+ # mock a monitoring process
+ pid = 111
+ reqid = "test_request_id"
+ MonitoringProcess.add({"request_id": reqid, "process_id": pid})
+
+ # test behaviour with not-existing request UUID
+ request = testing.DummyRequest()
+ request.matchdict["request_id"] = "unknown-request-uuid"
+ error_raised = False
+ try:
+ GraphAPI(request).get_graph_pipeline_status()
+ except HTTPNotFound:
+ error_raised = True
+ assert error_raised, "Error must have been raised for unrecognised request UUID."
+
+ # test the behaviour when the PID doesn't exist or another OSError is thrown
+ mock_process.side_effect = NoSuchProcess("error")
+ request = testing.DummyRequest()
+ request.matchdict["request_id"] = reqid
+ response = GraphAPI(request).get_graph_pipeline_status()
+ assert response == {"msg": "Monitoring process has been stopped or killed or terminated before this request was executed."}
+
+ # test behaviour with existing request UUID and existing PID
+ assert MonitoringProcess.exists(reqid)
+ mock_process.side_effect = None
+ mock_process.return_value.status = Mock(return_value=STATUS_SLEEPING)
+ request = testing.DummyRequest()
+ request.matchdict["request_id"] = reqid
+ response = GraphAPI(request).get_graph_pipeline_status()
+ assert response == {"status": STATUS_SLEEPING, "msg": "Successfully fetched status of graph pipeline process."}
+ mock_process.return_value.status.assert_called_with()
+
+ @patch('clmcservice.graphapi.views.Process')
+ def test_stop_graph_pipeline(self, mock_process):
+ """
+ Tests the functionality to stop a graph monitoring script.
+
+ :param mock_process: mock object to mimic the behavior of the psutil.Process functionality
"""
# mock a monitoring process
@@ -794,21 +834,23 @@ class TestGraphAPI(object):
assert error_raised, "Error must have been raised for unrecognised request UUID."
# test the behaviour when the PID doesn't exist or another OSError is thrown
- mock_kill.side_effect = OSError("error")
+ mock_process.side_effect = NoSuchProcess("error")
request = testing.DummyRequest()
request.matchdict["request_id"] = reqid
response = GraphAPI(request).stop_graph_pipeline()
- assert response == {"msg": "Monitoring process has been stopped before this request was executed."}
+ assert response == {"msg": "Monitoring process has been stopped or killed or terminated before this request was executed."}
# test behaviour with existing request UUID and existing PID
MonitoringProcess.add({"request_id": reqid, "process_id": pid})
assert MonitoringProcess.exists(reqid)
- mock_kill.side_effect = None
+ mock_process.side_effect = None
+ mock_process.return_value = Mock()
request = testing.DummyRequest()
request.matchdict["request_id"] = reqid
response = GraphAPI(request).stop_graph_pipeline()
assert response == {"msg": "Monitoring process has been successfully stopped."}
- mock_kill.assert_called_with(pid, SIGKILL) # assert that os.kill was called with termination signal
+ mock_process.return_value.terminate.assert_called_with()
+ mock_process.return_value.wait.assert_called_with(timeout=3)
assert not MonitoringProcess.exists(reqid), "Request ID must be removed when the process is killed."
@staticmethod
diff --git a/src/service/clmcservice/graphapi/views.py b/src/service/clmcservice/graphapi/views.py
index f7f2515..9232e81 100644
--- a/src/service/clmcservice/graphapi/views.py
+++ b/src/service/clmcservice/graphapi/views.py
@@ -34,8 +34,7 @@ from requests import exceptions, get
from uuid import uuid4
from json import load, dumps
from subprocess import Popen
-from os import kill
-from signal import SIGKILL
+from psutil import Process, NoSuchProcess, TimeoutExpired
from logging import getLogger
@@ -437,6 +436,32 @@ class GraphAPI(object):
log.warning("Graph pipeline process for SFC {0} with PID {1} has finished executing unexpectedly with return code {2}".format(sfc, process_pid, process_return_code))
raise HTTPInternalServerError("An unexpected error occurred while trying to start monitoring graph measurements for service function chain {0}".format(sfc))
+ @view_config(route_name='graph_manage_pipeline', request_method='GET')
+ def get_graph_pipeline_status(self):
+ """
+ An API endpoint to get the status of a monitoring graph pipeline script.
+
+ :return: A JSON response with the status of the background process.
+ """
+
+ request_id = self.request.matchdict['request_id'] # get the UUID of the request from the URL
+ process_id = MonitoringProcess.get(request_id)
+
+ if process_id is None:
+ raise HTTPNotFound("A monitoring process with ID {0} couldn't be found.".format(request_id))
+
+ # create a process management class instance
+ try:
+ process_obj = Process(process_id)
+ status = process_obj.status()
+ log.info("Fetching process status with request ID {0} and process ID {1}, status - {2}".format(request_id, process_id, status))
+ response = {"status": status, "msg": "Successfully fetched status of graph pipeline process."}
+ except NoSuchProcess as e:
+ log.warning("Unexpected error occurred when trying to get a process that is registered in the CLMC service, but doesn't exist on the OS - {0}".format(e))
+ response = {"msg": "Monitoring process has been stopped or killed or terminated before this request was executed."}
+
+ return response
+
@view_config(route_name='graph_manage_pipeline', request_method='DELETE')
def stop_graph_pipeline(self):
"""
@@ -451,13 +476,19 @@ class GraphAPI(object):
if process_id is None:
raise HTTPNotFound("A monitoring process with ID {0} couldn't be found.".format(request_id))
+ # create a process management class instance and terminate the process
try:
- kill(process_id, SIGKILL)
- log.info("Successfully stopped process with request ID {0} and process ID {1}".format(request_id, process_id))
+ process_obj = Process(process_id)
+ log.info("Terminating process with request ID {0} and process ID {1}, status before termination - {2}".format(request_id, process_id, process_obj.status()))
+ process_obj.terminate()
+ process_obj.wait(timeout=3)
response = {"msg": "Monitoring process has been successfully stopped."}
- except OSError as e:
- log.warning("Couldn't stop monitoring process with request ID {0} and process ID {1} due to error {2}".format(request_id, process_id, e))
- response = {"msg": "Monitoring process has been stopped before this request was executed."}
+ except TimeoutExpired as e:
+ log.error("Unexpected error occurred while waiting for a graph pipeline process to terminate - {0}".format(e))
+ raise HTTPInternalServerError("Termination of monitoring process couldn't be completed.")
+ except NoSuchProcess as e:
+ log.warning("Unexpected error occurred when trying to get a process that is registered in the CLMC service, but doesn't exist on the OS - {0}".format(e))
+ response = {"msg": "Monitoring process has been stopped or killed or terminated before this request was executed."}
MonitoringProcess.delete(request_id)
diff --git a/src/service/setup.py b/src/service/setup.py
index d1e8ccf..10eef05 100644
--- a/src/service/setup.py
+++ b/src/service/setup.py
@@ -66,6 +66,7 @@ requires = [
'tosca-parser==1.1.0',
'schema==0.6.8',
'requests==2.21.0',
+ 'psutil==5.6.1',
'pytest==3.8.1'
]
--
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