Added a random-traffic-generator for the Python Sample App (#31)

*Description of changes:*
Added a random-traffic-generator for the Python Sample App. More details
can be found in the README under
`aws-otel-python-instrumentation/sample-applications/vehicle-dealership-sample-app/random-traffic-generator`.

The traffic generator generates the following traffic:
1. Every minute, sends a single POST request to the VehicleInventoryApp
and sends a single GET request.
2. Every hour, sends a burst of requests: 5 POST requests to the
VehicleInventoryApp and 5 GET requests.
3. Every 5 minutes, sleeps for random amount of time between 30-60
seconds and then sends a GET request to the VehicleInventoryApp with a
random throttle param between 5-20 seconds. The backend reads that
throttle param and simulates throttling for that amount of time before
responding to the request.
4. Every 5 minutes, sleeps for random amount of time between 30-60
seconds and then sends a GET request to the VehicleInventoryApp with an
invalid car id to trigger 404 error.
5. Every 5 minutes, sleeps for random amount of time between 30-60
seconds and then sends a GET request to the ImageServiceApp with a non
existent image name to trigger 500 error due to S3 Error: "An error
occurred (NoSuchKey) when calling the GetObject operation: The specified
key does not exist."

By submitting this pull request, I confirm that you can use, modify,
copy, and redistribute this contribution, under the terms of your
choice.

sample-applications/vehicle-dealership-sample-app/VehicleInventoryApp/MainService/url.py

@@ -8,4 +8,5 @@
     path("", views.vehicle, name="vehicle"),
     path("<int:vehicle_id>", views.get_vehicle_by_id, name="get_vehicle_by_id"),
     path("<int:vehicle_id>/image", views.get_vehicle_image, name="get_vehicle_image"),
+    path("image/<str:image_name>", views.get_image_by_name, name="image_by_name"),
 ]

sample-applications/vehicle-dealership-sample-app/VehicleInventoryApp/MainService/views.py

@@ -2,9 +2,10 @@
 # SPDX-License-Identifier: Apache-2.0
 import json
 import os
+import time
 
 import requests
-from django.http import HttpResponse, HttpResponseBadRequest, HttpResponseNotAllowed
+from django.http import HttpResponse, HttpResponseBadRequest, HttpResponseNotAllowed, HttpResponseNotFound
 from django.views.decorators.csrf import csrf_exempt
 from dotenv import load_dotenv
 from MainService.models import Vehicle
@@ -27,8 +28,7 @@ def vehicle(request):
                 make=body["make"], model=body["model"], year=body["year"], image_name=body["image_name"]
             )
             vehicle_object.save()
-            print(get_image_endpoint() + "/images/name/" + body["image_name"])
-            requests.post(get_image_endpoint() + "/images/name/" + body["image_name"], timeout=10)
+            requests.post(build_image_url(body["image_name"]), timeout=10)
             return HttpResponse("VehicleId = " + str(vehicle_object.id))
         except KeyError as exception:
             return HttpResponseBadRequest("Missing key: " + str(exception))
@@ -40,14 +40,38 @@ def vehicle(request):
 
 def get_vehicle_by_id(request, vehicle_id):
     if request.method == "GET":
+        throttle_time = request.GET.get("throttle")
+        if throttle_time:
+            print("going to throttle for " + throttle_time + " seconds")
+            time.sleep(int(throttle_time))
+
         vehicle_objects = Vehicle.objects.filter(id=vehicle_id).values()
+        if not vehicle_objects:
+            return HttpResponseNotFound("Vehicle with id=" + str(vehicle_id) + " is not found")
         return HttpResponse(vehicle_objects)
     return HttpResponseNotAllowed("Only GET requests are allowed!")
 
 
 def get_vehicle_image(request, vehicle_id):
     if request.method == "GET":
         vehicle_object = Vehicle.objects.filter(id=vehicle_id).first()
+        if not vehicle_object:
+            return HttpResponseNotFound("Vehicle with id=" + str(vehicle_id) + " is not found")
         image_name = getattr(vehicle_object, "image_name")
-        return HttpResponse(requests.get(get_image_endpoint() + "/images/name/" + image_name, timeout=10))
+        return HttpResponse(requests.get(build_image_url(image_name), timeout=10))
+    return HttpResponseNotAllowed("Only GET requests are allowed!")
+
+
+@csrf_exempt
+def get_image_by_name(request, image_name):
+    print(image_name)
+    if request.method == "GET":
+        response = requests.get(build_image_url(image_name), timeout=10)
+        if response.ok:
+            return HttpResponse(response)
+        return HttpResponseNotFound("Image with name: " + image_name + " is not found")
     return HttpResponseNotAllowed("Only GET requests are allowed!")
+
+
+def build_image_url(image_name):
+    return get_image_endpoint() + "/images/name/" + image_name

sample-applications/vehicle-dealership-sample-app/random-traffic-generator/.gitignore

@@ -0,0 +1 @@
+node_modules

sample-applications/vehicle-dealership-sample-app/random-traffic-generator/Dockerfile

@@ -0,0 +1,26 @@
+# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+# Use the official lightweight Node.js 16 image.
+# https://hub.docker.com/_/node
+FROM node:16-slim
+
+# Create and change to the app directory.
+WORKDIR /usr/src/app
+
+# Copy application dependency manifests to the container image.
+# A wildcard is used to ensure copying both package.json AND package-lock.json (if available).
+# Copying this first prevents re-running npm install on every code change.
+COPY package*.json ./
+
+# Install production dependencies.
+# If you have native dependencies, you'll need additional tools.
+# For a full list of package.json changes, see:
+# https://github.com/nodejs/docker-node/blob/main/docs/BestPractices.md
+RUN npm install --only=production
+
+# Copy local code to the container image.
+COPY . .
+
+# Run the web service on container startup.
+CMD [ "node", "index.js" ]
+

sample-applications/vehicle-dealership-sample-app/random-traffic-generator/README.md

@@ -0,0 +1,21 @@
+# Random Traffic Generator
+The traffic generator generates the following traffic:
+1. Every minute, sends a single POST request to the VehicleInventoryApp and sends a single GET request.
+2. Every hour, sends a burst of requests: 5 POST requests to the VehicleInventoryApp and 5 GET requests.
+3. Every 5 minutes, sleeps for random amount of time between 30-60 seconds and then sends a GET request to the VehicleInventoryApp with a random throttle param between 5-20 seconds. The backend reads that throttle param and simulates throttling for that amount of time before responding to the request.
+4. Every 5 minutes, sleeps for random amount of time between 30-60 seconds and then sends a GET request to the VehicleInventoryApp with an invalid car id to trigger 404 error.
+5. Every 5 minutes, sleeps for random amount of time between 30-60 seconds and then sends a GET request to the ImageServiceApp with a non existent image name to trigger 500 error due to S3 Error: "An error occurred (NoSuchKey) when calling the GetObject operation: The specified key does not exist."
+
+## Running locally
+1. Run `npm install`
+2. Run locally:
+    - If you are running against you application locally, just run `node index.js`. The default endpoint is `0.0.0.0:8000` for the ImageServiceApp and `0.0.0.0:8001` for VehicleInventoryApp.
+    - If you want to run against the application on EKS, before running the `node index.js`, run `export <EKS_URL>`.
+
+## Deploying to EKS
+Run `bash build.sh <account_id> <region>`. This does the following:
+1. This will retrieve the endpoint from EKS ingress-nginx pod 
+2. Build docker image of the traffic
+3. Push the docker image to ECR 
+4. Deploy the image to EKS
+

sample-applications/vehicle-dealership-sample-app/random-traffic-generator/build.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+account=$1
+region=$2
+
+# Save the endpoint URL to a variable
+endpoint=$(kubectl get svc -n ingress-nginx | grep "ingress-nginx" | awk '{print $4}')
+
+# Print the endpoint
+echo "Endpoint: $endpoint"
+
+export REPOSITORY_PREFIX=${account}.dkr.ecr.${region}.amazonaws.com
+aws ecr get-login-password --region ${region} | docker login --username AWS --password-stdin ${REPOSITORY_PREFIX}
+aws ecr create-repository --repository-name random-traffic-generator --region ${region} || true
+docker build -t random-traffic-generator:latest .
+docker tag random-traffic-generator:latest ${REPOSITORY_PREFIX}/random-traffic-generator:latest
+docker push ${REPOSITORY_PREFIX}/random-traffic-generator:latest
+
+sed  -e 's#\${REPOSITORY_PREFIX}'"#${REPOSITORY_PREFIX}#g" -e 's#\${URL}'"#$endpoint#g" deployment.yaml | kubectl apply -f -
+
+

sample-applications/vehicle-dealership-sample-app/random-traffic-generator/deployment.yaml

@@ -0,0 +1,25 @@
+# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: random-traffic-generator
+  labels:
+    app: random-traffic-generator
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: random-traffic-generator
+  template:
+    metadata:
+      labels:
+        app: random-traffic-generator
+    spec:
+      containers:
+      - name: random-traffic-generator
+        image: ${REPOSITORY_PREFIX}/random-traffic-generator:latest
+        env:
+        - name: URL
+          value: "${URL}"
+

sample-applications/vehicle-dealership-sample-app/random-traffic-generator/index.js

@@ -0,0 +1,102 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+const axios = require('axios');
+const cron = require('node-cron');
+
+const vehicleURL = process.env.URL ? `${process.env.URL}/vehicle-inventory` : 'http://0.0.0.0:8001/vehicle-inventory'
+
+function getRandomNumber(min, max) {
+    return Math.floor(Math.random() * (max - min + 1)) + min;
+}
+
+
+function sleep(ms) {
+    return new Promise(resolve => setTimeout(resolve, ms));
+}
+
+console.log(vehicleURL)
+
+// sends two requests every minute, 1 POST request and 1 GET request
+const postGetCarsTrafficTask = cron.schedule('* * * * *', async () => {
+        console.log('add 1 car every 1 minutes');
+        const carData = {"make": "BMW", "model": "M340", "year": 2022, "image_name": "newCar.jpg"}
+        axios.post(`http://${vehicleURL}/`, carData, { timeout: 10000 })
+            .catch(err => {
+                console.error(err.response && err.response.data);
+            });
+
+        // gets image from image service through the vehicle service
+        axios.get(`http://${vehicleURL}/1/image`, { timeout: 10000 })
+            .catch(err => {
+                console.error(`${err.response}, ${err.response.data}`);
+            }); // Catch and log errors
+
+        axios.get(`http://${vehicleURL}/1`, { timeout: 10000 })
+            .catch(err => {
+                console.error(err.response && err.response.data);
+            }); // Catch and log errors
+}, { scheduled: false });
+postGetCarsTrafficTask.start();
+
+// sends a burst of traffic sending 10 requests every 15 mins:
+// 5 POST requests and 5 GET requests. 
+const postGetCarsTrafficBurstTask = cron.schedule('*/15 * * * *', async () => {
+    console.log('add 5 cars within 1 minutes');
+    const carData = {"make": "BMW", "model": "M340", "year": 2022, "image_name": "newCar.jpg"}
+    for (let i = 0; i < 5; i++) {
+        axios.post(`http://${vehicleURL}/`, carData, { timeout: 10000 })
+            .catch(err => {
+                console.error(err.response && err.response.data);
+            }); // Catch and log errors
+
+        // gets image from image service through the vehicle service
+        axios.get(`http://${vehicleURL}/1/image`, { timeout: 10000 })
+            .catch(err => {
+                console.error(err.response && err.response.data);
+            }); // Catch and log errors
+    }
+}, { scheduled: false });
+postGetCarsTrafficBurstTask.start();
+
+// sends a GET request with custom throttle parameter in the body that mimics being throttled. The throttle time
+// is going to be random between 2 - 5 secs.
+const getCarThrottle = cron.schedule('*/5 * * * *', async () => {    
+    sleepSecs = getRandomNumber(30,60);
+    console.log(`sleep ${sleepSecs} seconds`);
+    await sleep(sleepSecs*1000);
+    throttleSecs = getRandomNumber(2,5);
+    console.log(`request will be throttled for ${throttleSecs} seconds`)
+    axios.get(`http://${vehicleURL}/1`, {params: {"throttle": throttleSecs}}, { timeout: 10000 })
+        .catch(err => {
+            console.error(err.response && err.response.data);
+        }); // Catch and log errors
+}, { scheduled: false });
+getCarThrottle.start();
+
+// sends an invalid GET request with a non existent car id to trigger 404 error
+const getInvalidRequest = cron.schedule('*/5 * * * *', async () => {    
+    sleepSecs = getRandomNumber(30,120);
+    console.log(`sleep ${sleepSecs} seconds`);
+    await sleep(sleepSecs*1000);
+    console.log("getting non existent car to trigger 404");
+    axios.get(`http://${vehicleURL}/123456789`, { timeout: 10000 })
+        .catch(err => {
+            console.error(err.response && err.response.data);
+        }); // Catch and log errors
+}, { scheduled: false });
+getInvalidRequest.start();
+
+// sends an invalid GET request with a non existent image name to trigger 500 error due to S3 Error:
+// "An error occurred (NoSuchKey) when calling the GetObject operation: The specified key does not exist."
+// The vehicle service will then return 404.
+const getNonExistentImage = cron.schedule('*/5 * * * *', async () => {
+    sleepSecs = getRandomNumber(30,120);
+    console.log(`sleep ${sleepSecs} seconds`);
+    await sleep(sleepSecs*1000);
+    console.log('get an non existent image to trigger aws error');
+    axios.get(`http://${vehicleURL}/image/doesnotexist.jpeg`)
+        .catch(err => {
+            console.error(err.response && err.response.data);
+        }); // Catch and log errors
+}, { scheduled: false });
+getNonExistentImage.start();