Simulating traffic

🔑 Key points

Using curl, you can simulate data to help create and test visualizations for production use.

When building DevOps automation components—such as metrics, logs, or alerts—it is often necessary to simulate traffic to validate that the system responds correctly. While you could manually use a browser to generate requests, automating traffic with scripts is more efficient. One effective method is using curl commands wrapped in shell scripts.

Specifying the target host

First, define the host you want to target. If you are running the application in a local development environment, set the variable like this:

host=http://localhost:3000

If you are targeting a production system, set it to your service's URL:

host=https://pizza-service.yourdomainname.click

Common endpoint calls

The following examples demonstrate how to simulate various user behaviors.

Note

You must use a POSIX-compliant environment (such as Linux or macOS) to run these scripts. On Windows, you can use Git Bash. These commands also require jq for processing JSON and assume you have populated your database using the JWT Pizza Data instructions.

Request the menu every three seconds

This script simulates a user browsing the menu at regular intervals.

while true; do
  curl -s "$host/api/order/menu"
  sleep 3
done

Attempt an invalid login every 25 seconds

This simulates failed authentication attempts, which is useful for testing security alerts.

while true; do
  curl -s -X PUT "$host/api/auth" \
    -d '{"email":"unknown@jwt.com", "password":"bad"}' \
    -H 'Content-Type: application/json'
  sleep 25
done

Login and logout two minutes later

This simulates a user session that lasts for two minutes.

while true; do
  response=$(curl -s -X PUT "$host/api/auth" -d '{"email":"f@jwt.com", "password":"franchisee"}' -H 'Content-Type: application/json')
  token=$(echo "$response" | jq -r '.token')
  sleep 110
  curl -s -X DELETE "$host/api/auth" -H "Authorization: Bearer $token"
  sleep 10
done

Login, buy a pizza, and logout

This script simulates a complete successful transaction: logging in, placing an order, waiting 20 seconds, and logging out.

while true; do
  response=$(curl -s -X PUT "$host/api/auth" -d '{"email":"d@jwt.com", "password":"diner"}' -H 'Content-Type: application/json')
  token=$(echo "$response" | jq -r '.token')
  curl -s -X POST "$host/api/order" \
    -H 'Content-Type: application/json' \
    -H "Authorization: Bearer $token" \
    -d '{"franchiseId": 1, "storeId":1, "items":[{ "menuId": 1, "description": "Veggie", "price": 0.05 }]}'
  sleep 20
  curl -s -X DELETE "$host/api/auth" -H "Authorization: Bearer $token"
  sleep 30
done

Simulate a failed order (too many pizzas)

This script attempts to order more pizzas than the system allows (e.g., 22 pizzas), causing a server error. This is useful for testing how your monitoring system handles 500 status codes.

while true; do
  response=$(curl -s -X PUT "$host/api/auth" -d '{"email":"d@jwt.com", "password":"diner"}' -H 'Content-Type: application/json')
  token=$(echo "$response" | jq -r '.token')
  echo "Login hungry diner..."

  items='{ "menuId": 1, "description": "Veggie", "price": 0.05 }'
  for (( i=0; i < 21; i++ ))
  do 
    items+=', { "menuId": 1, "description": "Veggie", "price": 0.05 }'
  done

  curl -s -X POST "$host/api/order" \
    -H 'Content-Type: application/json' \
    -H "Authorization: Bearer $token" \
    -d "{\"franchiseId\": 1, \"storeId\":1, \"items\":[$items]}"
  
  echo "Bought too many pizzas..."
  sleep 5
  curl -s -X DELETE "$host/api/auth" -H "Authorization: Bearer $token" > /dev/null
  echo "Logging out hungry diner..."
  sleep 295
done