Run the producer by executing the following command: 
node producer.js
You should see output resembling this: 
Produced event to topic purchases: key = jsmith     value = alarm clock
Produced event to topic purchases: key = htanaka    value = alarm clock
Produced event to topic purchases: key = sgarcia    value = book
Produced event to topic purchases: key = htanaka    value = batteries
Produced event to topic purchases: key = sgarcia    value = gift card
Produced event to topic purchases: key = jsmith     value = gift card
Produced event to topic purchases: key = sgarcia    value = t-shirts
Produced event to topic purchases: key = awalther   value = alarm clock
Produced event to topic purchases: key = eabara     value = batteries
Produced event to topic purchases: key = jsmith     value = gift card