added prometheus metrics to some services

cart/package.json

@@ -16,6 +16,7 @@
       "pino": "^5.10.8",
       "express-pino-logger": "^4.0.0",
       "pino-pretty": "^2.5.0",
-      "@instana/collector": "^1.65.0"
+      "@instana/collector": "^1.65.0",
+      "prom-client": "^11.5.3"
   }
 }

cart/server.js

@@ -13,6 +13,16 @@ const bodyParser = require('body-parser');
 const express = require('express');
 const pino = require('pino');
 const expPino = require('express-pino-logger');
+// Prometheus
+const promClient = require('prom-client');
+const Registry = promClient.Registry;
+const register = new Registry();
+const counter = new promClient.Counter({
+    name: 'items_added',
+    help: 'running count of items added to cart',
+    registers: [register]
+});
+
 
 var redisConnected = false;
 
@@ -49,6 +59,12 @@ app.get('/health', (req, res) => {
     res.json(stat);
 });
 
+// Prometheus
+app.get('/metrics', (req, res) => {
+    res.header('Content-Type', 'text/plain');
+    res.send(register.metrics());
+});
+
 
 // get cart with id
 app.get('/cart/:id', (req, res) => {
@@ -165,6 +181,7 @@ app.get('/add/:id/:sku/:qty', (req, res) => {
 
                 // save the new cart
                 saveCart(req.params.id, cart).then((data) => {
+                    counter.inc(qty);
                     res.json(cart);
                 }).catch((err) => {
                     req.log.error(err);

payment/payment.py

@@ -9,16 +9,28 @@ import traceback
 import opentracing as ot
 import opentracing.ext.tags as tags
 from flask import Flask
+from flask import Response
 from flask import request
 from flask import jsonify
 from rabbitmq import Publisher
+# Prometheus
+import prometheus_client
+from prometheus_client import Counter, Histogram
 
 app = Flask(__name__)
+app.logger.setLevel(logging.INFO)
 
 CART = os.getenv('CART_HOST', 'cart')
 USER = os.getenv('USER_HOST', 'user')
 PAYMENT_GATEWAY = os.getenv('PAYMENT_GATEWAY', 'https://paypal.com/')
 
+# Prometheus
+PromMetrics = {}
+PromMetrics['SOLD_COUNTER'] = Counter('sold_count', 'Running count of items sold')
+PromMetrics['AUS'] = Histogram('units_sold', 'Avergae Unit Sale', buckets=(1, 2, 5, 10, 100))
+PromMetrics['AVS'] = Histogram('cart_value', 'Avergae Value Sale', buckets=(100, 200, 500, 1000, 2000, 5000, 10000))
+
+
 @app.errorhandler(Exception)
 def exception_handler(err):
     app.logger.error(str(err))
@@ -28,6 +40,16 @@ def exception_handler(err):
 def health():
     return 'OK'
 
+# Prometheus
+@app.route('/metrics', methods=['GET'])
+def metrics():
+    res = []
+    for m in PromMetrics.values():
+        res.append(prometheus_client.generate_latest(m))
+
+    return Response(res, mimetype='text/plain')
+
+
 @app.route('/pay/<id>', methods=['POST'])
 def pay(id):
     app.logger.info('payment for {}'.format(id))
@@ -71,6 +93,13 @@ def pay(id):
     if req.status_code != 200:
         return 'payment error', req.status_code
 
+    # Prometheus
+    # items purchased
+    item_count = countItems(cart.get('items', []))
+    PromMetrics['SOLD_COUNTER'].inc(item_count)
+    PromMetrics['AUS'].observe(item_count)
+    PromMetrics['AVS'].observe(cart.get('total', 0))
+
     # Generate order id
     orderid = str(uuid.uuid4())
     queueOrder({ 'orderid': orderid, 'user': id, 'cart': cart })
@@ -133,6 +162,15 @@ def queueOrder(order):
             publisher.publish(order, headers)
 
 
+def countItems(items):
+    count = 0
+    for item in items:
+        if item.get('sku') != 'SHIP':
+            count += item.get('qty')
+
+    return count
+
+
 # RabbitMQ
 publisher = Publisher(app.logger)
 
@@ -140,9 +178,6 @@ if __name__ == "__main__":
     sh = logging.StreamHandler(sys.stdout)
     sh.setLevel(logging.INFO)
     fmt = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s')
-    #sh.setFormatter(fmt)
-    #app.logger.addHandler(sh)
-    app.logger.setLevel(logging.INFO)
     app.logger.info('Payment gateway {}'.format(PAYMENT_GATEWAY))
     port = int(os.getenv("SHOP_PAYMENT_PORT", "8080"))
     app.logger.info('Starting on port {}'.format(port))

payment/requirements.txt

@@ -2,4 +2,5 @@ uwsgi
 Flask
 requests
 pika
+prometheus_client
 instana