Gunicorn plumbing

Dockerfile

@@ -16,4 +16,26 @@ COPY . /src/ngsi-timeseries-api/
 WORKDIR /src/ngsi-timeseries-api/src
 ENV PYTHONPATH=$PWD:$PYTHONPATH
 
-CMD python app.py
+EXPOSE 8668
+ENTRYPOINT ["python", "app.py"]
+# NOTE.
+# The above is basically the same as running:
+#
+#     gunicorn server.wsgi --config server/gconfig.py
+#
+# You can also pass any valid Gunicorn option as container command arguments
+# to add or override options in server/gconfig.py---see `server.grunner` for
+# the details.
+# In particular, a convenient way to reconfigure Gunicorn is to mount a config
+# file on the container and then run the container with the following option
+#
+#     --config /path/to/where/you/mounted/your/gunicorn.conf.py
+#
+# as in the below example
+#
+#     $ echo 'workers = 2' > gunicorn.conf.py
+#     $ docker run -it --rm \
+#                  -p 8668:8668 \
+#                  -v $(pwd)/gunicorn.conf.py:/gunicorn.conf.py
+#                  smartsdk/quantumleap --config /gunicorn.conf.py
+#

Pipfile

@@ -11,6 +11,7 @@ flask = "~=1.1.0"
 geocoder = "~=1.33"
 geojson = "~=2.4"
 geomet = "~=0.2"
+gunicorn = "~=20.0.4"
 influxdb = "~=4.0"
 pg8000 = ">=1.15"
 pymongo = "~=3.4"

src/app.py

@@ -1,12 +1,15 @@
-from utils.hosts import LOCAL
+import server.wsgi as flask
+import server.grunner as gunicorn
+from utils.cfgreader import EnvReader, BoolVar
+
+
+def use_flask() -> bool:
+    env_var = BoolVar('USE_FLASK', False)
+    return EnvReader().safe_read(env_var)
 
 
 if __name__ == '__main__':
-    import connexion
-    app = connexion.FlaskApp(__name__, specification_dir='../specification/')
-    app.add_api('quantumleap.yml',
-                arguments={'title': 'QuantumLeap V2 API'},
-                pythonic_params=True,
-                # validate_responses=True, strict_validation=True
-                )
-    app.run(host=LOCAL, port=8668)
+    if use_flask():  # dev mode, run the WSGI app in Flask dev server
+        flask.run()
+    else:            # prod mode, run the WSGI app in Gunicorn
+        gunicorn.run()

src/geocoding/tests/test_geocoding.py

@@ -94,6 +94,8 @@ def test_entity_add_street_line(air_quality_observed):
     assert len(geo['coordinates']) > 1
 
 
+# TODO: see #358
+@pytest.mark.skip(reason="see #358")
 def test_entity_add_city_shape(air_quality_observed):
     air_quality_observed.pop('location')
 

src/reporter/tests/run_tests.sh

@@ -3,7 +3,7 @@
 docker build -t smartsdk/quantumleap ../../../
 
 docker-compose up -d
-sleep 12
+sleep 20
 
 cd ../../../
 pytest src/reporter/ --cov-report= --cov-config=.coveragerc --cov-append --cov=src/

src/server/__init__.py

@@ -0,0 +1,3 @@
+
+DEFAULT_HOST = '0.0.0.0'  # bind to all available network interfaces
+DEFAULT_PORT = 8668

src/server/gconfig.py

@@ -0,0 +1,74 @@
+#
+# Gunicorn settings to run QuantumLeap.
+# To make configuration more manageable, we keep all our Gunicorn settings
+# in this file and start Gunincorn from the Docker container without any
+# command line args except for the app module and the path to this config
+# file, e.g.
+#
+#     gunicorn server.wsgi --config server/gconfig.py
+#
+# Settings spec:
+# - https://docs.gunicorn.org/en/stable/settings.html
+#
+
+import multiprocessing
+
+import server
+
+
+#
+# Server config section.
+#
+
+bind = f"{server.DEFAULT_HOST}:{server.DEFAULT_PORT}"
+
+
+#
+# Worker processes config section.
+# Read: https://docs.gunicorn.org/en/latest/design.html
+#
+
+
+# Number of worker processes for handling requests.
+# We set it to the max Gunicorn recommends.
+workers = multiprocessing.cpu_count() * 4 + 1
+
+# QuantumLeap does alot of network IO, so we configure worker processes
+# to use multi-threading (`gthread`) to improve performance. With this
+# setting, each request gets handled in its own thread taken from a
+# thread pool.
+# In our tests, the `gthread` worker type had better throughput and
+# latency than `gevent` but `gevent` used up less memory, most likely
+# because of the difference in actual OS threads. So for now we go with
+# `gthread` and a low number of threads. This has the advantage of better
+# performance, reasonable memory consumption, and keeps us from accidentally
+# falling into the `gevent` monkey patching rabbit hole. Also notice that
+# according to Gunicorn docs, when using `gevent`, Psycopg (Timescale
+# driver) needs psycogreen properly configured to take full advantage
+# of async IO. (Not sure what to do for the Crate driver!)
+worker_class = 'gthread'
+
+# The size of each process's thread pool.
+# So here's the surprise. In our tests, w/r/t to throughput `gthread`
+# outperformed `gevent`---27% better. Latency was pretty much the same
+# though. But the funny thing is that we used exactly the same number
+# of worker processes and the default number of threads per process,
+# which is, wait for it, 1. Yes, 1.
+#
+# TODO: proper benchmarking.
+# We did some initial quick & dirty benchmarking to get these results.
+# We'll likely have to measure better and also understand better the
+# way the various Gunicorn worker types actually work. (Pun intended.)
+threads = 1
+
+
+#
+# Logging config section.
+#
+
+loglevel = 'debug'
+
+
+# TODO: other settings.
+# Review gunicorn default settings with an eye on security and performance.
+# We might need to set more options than the above.

src/server/grunner.py

@@ -0,0 +1,81 @@
+import sys
+from typing import Any, Dict
+
+from gunicorn.app.base import Application
+from gunicorn.config import make_settings
+
+import server.gconfig
+from server.wsgi import application
+
+
+def quantumleap_base_config() -> Dict[str, Any]:
+    """
+    Read the base QuantumLeap configuration from the ``server.gconfig``
+    module.
+
+    :return: the dictionary with the base QuantumLeap settings.
+    """
+    gunicorn_setting_names = [k for k, v in make_settings().items()]
+    server_config_vars = vars(server.gconfig).items()
+    return {
+        k: v
+        for k, v in server_config_vars if k in gunicorn_setting_names
+    }
+
+
+class GuantumLeap(Application):
+    """
+    Gunicorn server runner.
+
+    This class is a fully-fledged Gunicorn server WSGI runner, just like
+    ``WSGIApplication`` from ``gunicorn.app.wsgiapp``, except the WSGI
+    app to run is fixed (QuantumLeap) and the content of ``server.gconfig``
+    is used as initial configuration. Notice you can override these base
+    config settings using CLI args or/and a config file as you'd normally
+    do with Gunicorn, but you can't run any WSGI app other than QuantumLeap.
+    """
+
+    def init(self, parser, opts, args):
+        return quantumleap_base_config()
+
+    def load(self):
+        return application
+
+
+def run():
+    """
+    Start a fully-fledged Gunicorn server to run QuantumLeap.
+
+    If you pass no CLI args, this is the same as running
+
+    ``$ gunicorn server.wsgi --config server/gconfig.py``
+
+    which starts Gunicorn to run the QuantumLeap WSGI Flask app with
+    the Gunicorn settings in our ``server.gconfig`` module.
+    You can specify any valid Gunicorn CLI option and it'll take
+    precedence over any setting with the same name in ``server.gconfig``.
+    Also you can specify a different config module and options in that
+    module will override those with the same name in ``server.gconfig``.
+    The only thing you won't be able to change is the WSGI app to run,
+    QuantumLeap.
+    """
+    gunicorn = GuantumLeap('%(prog)s [OPTIONS] [APP_MODULE]')  # (1)
+    sys.argv[0] = 'quantumleap'                                # (2)
+    sys.exit(gunicorn.run())                                   # (2)
+
+# NOTE.
+# 1. We keep the same usage as in `gunicorn.app.wsgiapp.run`.
+# 2. We basically start Gunicorn in the same way as the Gunicorn launcher
+# would:
+#
+# $ cat $(which gunicorn)
+#
+# #!/Users/andrea/.local/share/virtualenvs/ngsi-timeseries-api-MeJ80LMF/bin/python
+# # -*- coding: utf-8 -*-
+# import re
+# import sys
+# from gunicorn.app.wsgiapp import run
+# if __name__ == '__main__':
+#     sys.argv[0] = re.sub(r'(-script\.pyw|\.exe)?$', '', sys.argv[0])
+#     sys.exit(run())
+#

src/server/wsgi.py

@@ -0,0 +1,54 @@
+from connexion import FlaskApp
+
+import server
+
+
+SPEC_DIR = '../../specification/'
+SPEC = 'quantumleap.yml'
+
+
+def new_wrapper() -> FlaskApp:
+    """
+    Factory function to build a Connexion wrapper to manage the Flask
+    application in which QuantumLeap runs.
+
+    :return: the Connexion wrapper.
+    """
+    wrapper = FlaskApp(__name__,
+                       specification_dir=SPEC_DIR)
+    wrapper.add_api(SPEC,
+                    arguments={'title': 'QuantumLeap V2 API'},
+                    pythonic_params=True,
+                    # validate_responses=True, strict_validation=True
+                    )
+    return wrapper
+
+
+quantumleap = new_wrapper()
+"""
+Singleton Connexion wrapper that manages the QuantumLeap Flask app.
+"""
+
+application = quantumleap.app
+"""
+The WSGI callable to run QuantumLeap in a WSGI container of your choice,
+e.g. Gunicorn, uWSGI.
+Notice that Gunicorn will look for a WSGI callable named `application` if
+no variable name follows the module name given on the command line. So one
+way to run QuantumLeap in Gunicorn would be
+
+    gunicorn server.wsgi --config server/gconfig.py
+
+An even more convenient way is to use our Gunicorn standalone server,
+see `server.grunner` module.
+"""
+
+
+def run():
+    """
+    Runs the bare-bones QuantumLeap WSGI app.
+    Notice the app will run in the Flask dev server, so it's only good
+    for development, not prod!
+    """
+    quantumleap.run(host=server.DEFAULT_HOST,
+                    port=server.DEFAULT_PORT)

src/tests/docker-compose.yml

@@ -21,7 +21,9 @@ services:
       - "27017:27017"
 
   quantumleap:
-    image: ${QL_IMAGE:-smartsdk/quantumleap}
+    image: ${QL_IMAGE:-smartsdk/quantumleap:latest}
+    sysctls:
+      net.core.somaxconn: 4096
     ports:
       - "8668:8668"
     depends_on:
@@ -33,7 +35,7 @@ services:
       - USE_GEOCODING=True
       - REDIS_HOST=redis
       - REDIS_PORT=6379
-      - LOGLEVEL=DEBUG
+      - LOGLEVEL=ERROR
 
   crate:
     image: crate:${CRATE_VERSION:-4.1.4}

src/tests/notify-load-test.js

@@ -0,0 +1,49 @@
+import http from 'k6/http';
+import { check, sleep } from 'k6';
+
+export default function() {
+  var url = 'http://192.0.0.1:8668/v2/notify';
+  const before = new Date().getTime();
+  const T = 30; // time needed to complete a VU iteration
+
+
+  for (var i = 0; i < 100; i++){
+      var data = {
+                "id": "Room:1",
+                "type": "Room",
+                "temperature": {
+                        "value": 23,
+                        "type": "Float"
+                },
+                "pressure": {
+                        "value": 720,
+                        "type": "Integer"
+                    }
+                }
+      var array = [];
+      array.push(data);
+
+      var payload = {
+        "data" : array
+      }
+      var payload = JSON.stringify(payload);
+
+      var params = {
+        headers: {
+          'Content-Type': 'application/json',
+        }
+      };
+      let res = http.post(url, payload, params);
+      check(res, { 'status was 200': r => r.status == 200 });
+  }
+  const after = new Date().getTime();
+  const diff = (after - before) / 1000;
+  const remainder = T - diff;
+  if (remainder > 0) {
+    sleep(remainder);
+  } else {
+    console.warn(
+      `Timer exhausted! The execution time of the test took longer than ${T} seconds`
+    );
+  }
+}

src/tests/run_load_tests.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+
+docker build --cache-from smartsdk/quantumleap -t smartsdk/quantumleap ../../
+
+docker-compose up -d
+docker-compose stop orion
+docker-compose stop mongo
+sleep 10
+
+docker run -i --rm loadimpact/k6 run --vus 10 --duration 60s - < notify-load-test.js
+
+sleep 10
+
+docker run -i --rm loadimpact/k6 run --vus 100 --duration 120s - < notify-load-test.js
+
+sleep 10
+
+docker-compose down

src/tests/run_tests.sh

@@ -24,7 +24,7 @@ docker run -ti --rm --network tests_default \
 # Restart QL on development version and CRATE on current version
 docker-compose stop quantumleap
 CRATE_VERSION=${CRATE_VERSION} QL_IMAGE=smartsdk/quantumleap docker-compose up -d
-sleep 30
+sleep 40
 
 # Backwards Compatibility Test
 cd ../../