Created detailed example of using sanic. Adds configurations based on various environment variables, handles database access (using aioredis), uses middleware to check for db object and attach it to request object, and logs events to a logfile (which is set using environment variables).

examples/detailed_example.py

@@ -0,0 +1,96 @@
+import json
+import logging
+import os
+
+import aioredis
+
+import sanic
+from sanic import Sanic
+
+
+ENV_VARS = ["REDIS_HOST", "REDIS_PORT",
+            "REDIS_MINPOOL", "REDIS_MAXPOOL",
+            "REDIS_PASS", "APP_LOGFILE"]
+
+app = Sanic(name=__name__)
+
+logger = None
+
+
+@app.middleware("request")
+async def attach_db_connectors(request):
+    if not hasattr(request.app.config, "REDIS"):
+        logger.info("Setting up connection to Redis Cache")
+        request.app.config.REDIS = await aioredis.create_pool((app.config.REDIS_HOST, int(app.config.REDIS_PORT)),
+                                                              minsize=int(app.config.REDIS_MINPOOL),
+                                                              maxsize=int(app.config.REDIS_MAXPOOL),
+                                                              password=app.config.REDIS_PASS)
+    # Just put the db objects in the request for easier access
+    request["redis"] = request.app.config.REDIS
+
+
+@app.route("/state/<user_id>", methods=["GET"])
+async def access_state(request, user_id):
+    try:
+        # Check to see if the value is in cache, if so lets return that
+        with await request["redis"] as redis_conn:
+            state = await redis_conn.get(user_id, encoding="utf-8")
+            if state:
+                return sanic.response.json(json.loads(state))
+        # Then state object is not in redis
+        logger.critical("Unable to find user_data in cache.")
+        return sanic.response.HTTPResponse({"msg": "User state not found"}, status=404)
+
+    except aioredis.ProtocolError:
+        logger.critical("Unable to connect to state cache")
+        return sanic.response.HTTPResponse({"msg": "Internal Server Error"}, status=500)
+
+
+@app.route("/state/<user_id>/push", methods=["POST"])
+async def set_state(request, user_id):
+    try:
+        with await request["redis"] as redis_conn:
+            # Set the value in cache to your new value
+            await redis_conn.set(user_id, json.dumps(request.json), expire=1800)
+            logger.info("Successfully retrieved from cache")
+            return sanic.response.HTTPResponse({"msg": "Successfully pushed state to cache"})
+    except aioredis.ProtocolError:
+        logger.critical("UNable to connect to state cache")
+        return sanic.response.HTTPResponse({"msg": "Interal Server Error"}, status=500)
+
+
+def configure():
+    # Setup environment variables
+    env_vars = [os.environ.get(v, None) for v in ENV_VARS]
+    if not all(env_vars):
+        # Send back environment variables that were not set
+        return False, [ENV_VARS[i] for i, flag in env_vars if not flag]
+    else:
+        app.config.update({k: v for k, v in zip(ENV_VARS, env_vars)})
+        setup_logging()
+        logging.info("Configuraiton complete")
+    return True, []
+
+def setup_logging():
+    logging_format = "[%(asctime)s] %(process)d-%(levelname)s "
+    logging_format += "%(module)s::%(funcName)s():l%(lineno)d: "
+    logging_format += "%(message)s"
+
+    print(app.config.APP_LOGFILE)
+    logging.basicConfig(
+        filename=app.config.APP_LOGFILE,
+        format=logging_format,
+        level=logging.DEBUG
+    )
+
+if __name__ == "__main__":
+    result, missing = configure()
+    logger = logging.getLogger()
+    if result:
+        try:
+            app.run(host="0.0.0.0", port=8080, debug=True)
+        except:
+            logger.critical("User killed server. Closing")
+    else:
+        need_string = ", ".join(missing)
+        logger.critical("Unable to start. Missing environment variables [{0}]".format(need_string))