Make SDX Local Controller a WSGI app

.gitignore

@@ -16,7 +16,7 @@ test-db
 
 # Ignore copies of env
 env.*
-.env
+.env*
 
 # Ignore files written by code coverage tools
 .coverage

.hadolint.yml

@@ -0,0 +1,7 @@
+ignored:
+  # DL3013 recommends that Python dependencies be pinned, but we
+  # probably do not want to do that right now.  Unpinned dependencies
+  # has been working okay for us so far, and pinning (using pip-tools
+  # would be ideal) should be done separately after a discussion,
+  # because that would change the workflow a bit.
+  - DL3013

Dockerfile

@@ -5,10 +5,13 @@ WORKDIR /usr/src/app
 
 COPY . /usr/src/app
 
-RUN pip3 install --no-cache-dir .
+# create a venv.
+RUN python3 -m venv /opt/venv --upgrade-deps
 
-EXPOSE 8080
+# Make sure we use the venv.
+ENV PATH="/opt/venv/bin:$PATH"
+ENV VIRTUAL_ENV="/opt/venv"
 
-ENTRYPOINT ["python3"]
+RUN pip3 install --no-cache-dir .[wsgi]
 
-CMD ["-m", "sdx_lc"]
+CMD ["./entrypoint.sh"]

README.md

@@ -79,7 +79,7 @@ example -- see above), and then run the server:
 
 ```console
 $ source .env
-$ python3 -m sdx_lc
+$ flask --app sdx_lc.app:app run --debug
 ```
 
 
@@ -123,7 +123,6 @@ $ source ./venv/bin/activate
 $ pip3 install --editable .[test]
 $ pytest
 ```
-`
 
 ## Communication between SDX Controller and Local Controller
 

entrypoint.sh

@@ -0,0 +1,10 @@
+#! /bin/sh
+
+# A helper script that can be executed off docker, just so that
+# uvicorn will print the right port number.  Docker will not do
+# environment variable substitution in CMD lines, so this script
+# became necessary.
+
+set -eu
+
+python3 -m uvicorn sdx_lc.app:asgi_app --host 0.0.0.0 --port "$SDXLC_PORT"

pyproject.toml

@@ -26,6 +26,7 @@ dependencies = [
     "setuptools >= 21.0.0",
     "pika >= 1.2.0",
     "connexion[swagger-ui] == 2.14.2",
+    "asgiref >= 3.7.2",    
     "pymongo > 3.0",
 ]
 
@@ -43,6 +44,9 @@ format = [
     "black == 24.*",
     "isort == 5.*",
 ]
+wsgi = [
+    "uvicorn"
+]
 
 [options.packages.find]
 where = "sdx_lc"

sdx_lc/__main__.py → sdx_lc/app.py

@@ -1,31 +1,18 @@
 #!/usr/bin/env python3
 
-import argparse
-import json
 import logging
 import os
 import threading
-import time
-from optparse import OptionParser
+from queue import Queue
 from subprocess import call
 
 import connexion
+from asgiref.wsgi import WsgiToAsgi
+from flask import redirect
 
 from sdx_lc import encoder
-from sdx_lc.messaging.topic_queue_consumer import *
-from sdx_lc.utils.db_utils import *
-
-logger = logging.getLogger(__name__)
-logging.getLogger("pika").setLevel(logging.WARNING)
-LOG_FILE = os.environ.get("LOG_FILE")
-
-
-def is_json(myjson):
-    try:
-        json.loads(myjson)
-    except ValueError as e:
-        return False
-    return True
+from sdx_lc.messaging.topic_queue_consumer import TopicQueueConsumer
+from sdx_lc.utils.db_utils import DbUtils
 
 
 def start_consumer(thread_queue, db_instance):
@@ -37,9 +24,6 @@ def start_consumer(thread_queue, db_instance):
         function.
     """
 
-    MESSAGE_ID = 0
-    HEARTBEAT_ID = 0
-
     rpc = TopicQueueConsumer(thread_queue=thread_queue, exchange_name="connection")
     t1 = threading.Thread(target=rpc.start_consumer, args=())
     t1.start()
@@ -51,22 +35,32 @@ def start_pull_topology_change():
     call(["python", "sdx_lc/jobs/pull_topo_changes.py"])
 
 
-def main():
-    if LOG_FILE:
-        logging.basicConfig(filename=LOG_FILE, level=logging.INFO)
+def create_app():
+    """
+    Create a Flas/Connexion App.
+    """
+
+    logger = logging.getLogger(__name__)
+    logging.getLogger("pika").setLevel(logging.WARNING)
+
+    log_file = os.getenv("LOG_FILE")
+
+    if log_file:
+        logging.basicConfig(filename=log_file, level=logging.INFO)
     else:
         logging.basicConfig(level=logging.INFO)
 
+    logger.info(
+        f"SDX Local Controller starting up ("
+        f"name: {os.getenv('SDXLC_NAME')}, "
+        f"domain: {os.getenv('SDXLC_DOMAIN')})"
+    )
+
     # Run swagger service
     app = connexion.App(__name__, specification_dir="./swagger/")
     app.app.json_encoder = encoder.JSONEncoder
     app.add_api("swagger.yaml", arguments={"title": "SDX LC"}, pythonic_params=True)
 
-    # Run swagger in a thread
-    threading.Thread(
-        target=lambda: app.run(port=os.getenv("SDXLC_PORT") or 8080)
-    ).start()
-
     # Start pulling topology changes from domain controller in a
     # separate subprocess
     processThread = threading.Thread(target=start_pull_topology_change)
@@ -75,9 +69,37 @@ def main():
     # Get DB connection and tables set up.
     db_instance = DbUtils()
     db_instance.initialize_db()
+
+    # Consume connection/link messages
     thread_queue = Queue()
     start_consumer(thread_queue, db_instance)
 
+    return app.app
+
+
+# We can run the app using flask, like so:
+#
+#     $ flask --app sdx_lc.app:app run --debug
+#
+# Or with an WSGI server such as gunicorn:
+#
+#     $ gunicorn --bind localhost:$SDXLC_PORT sdx_lc.app:app
+#
+app = create_app()
+
+# We use WsgiToAsgi adapter so that we can use an ASGI server (such as
+# uvicorn or hypercorn), like so:
+#
+#     $ uvicorn sdx_lc.app:asgi_app --host 0.0.0.0 --port $SDXLC_PORT
+#
+asgi_app = WsgiToAsgi(app)
+
+
+# Set up a redirect for convenience.
+@app.route("/", methods=["GET"])
+def index():
+    return redirect("/SDX-LC/2.0.0/ui/")
+
 
 if __name__ == "__main__":
-    main()
+    app.run(port=os.getenv("SDXLC_PORT") or 8080)