Measure DB call time

post-py/post_app.py

@@ -1,9 +1,14 @@
-from flask import Flask, request
+from flask import Flask, request, Response
 from pymongo import MongoClient
 from bson.objectid import ObjectId
 from bson.json_util import dumps
 from helpers import health
 import os
+import prometheus_client
+import time
+
+CONTENT_TYPE_LATEST = str('text/plain; version=0.0.4; charset=utf-8')
+REQUEST_DB_LATENCY = prometheus_client.Histogram('post_read_db_seconds', 'Request DB time')
 
 mongo_host = os.getenv('POST_DATABASE_HOST', '127.0.0.1')
 mongo_port = os.getenv('POST_DATABASE_PORT', '27017')
@@ -15,6 +20,10 @@
 app = Flask(__name__)
 
 
+@app.route('/metrics')
+def metrics():
+    return Response(prometheus_client.generate_latest(), mimetype=CONTENT_TYPE_LATEST)
+
 @app.route("/posts")
 def posts():
     posts = mongo_db.find().sort('created_at', -1)
@@ -42,7 +51,11 @@ def add_post():
 
 @app.route("/post/<id>")
 def get_post(id):
+    start_time = time.time()
     post = mongo_db.find_one({'_id': ObjectId(id)})
+    stop_time = time.time()  # + 0.3
+    resp_time = stop_time - start_time
+    REQUEST_DB_LATENCY.observe(resp_time)
     return dumps(post)
 
 

post-py/requirements.txt

@@ -0,0 +1,3 @@
+prometheus_client==0.0.21
+flask==0.12.2
+pymongo==3.5.1