Distributed Task scheduler using RabbitMQ

This is a sample demonstrating how to achieve a delayed task execution using RabbitMQ deadLetterExchange and message expiration time.

Checkout the medium article

Consumer

Consumer 1

Name : Email-Service-1

Start Email-Service-1.

APP_NAME=Email-Service-1 PORT=4000 yarn start

Setup Email-Service-1 to consume greet task type.

curl --location --request POST 'http://localhost:4000/setupConsumer' \
--header 'Content-Type: application/json' \
--data-raw '{
    "taskType":"greet"
}'

Setup Email-Service-1 to consume offer-notification task type.

curl --location --request POST 'http://localhost:4000/setupConsumer' \
--header 'Content-Type: application/json' \
--data-raw '{
    "taskType":"offer-notification"
}'

Consumer 2

Name : Email-Service-2

Start Email-Service-2.

APP_NAME=Email-Service-2 PORT=4001 yarn start

Setup Email-Service-2 to consume offer-notification task type.

curl --location --request POST 'http://localhost:4001/setupConsumer' \
--header 'Content-Type: application/json' \
--data-raw '{
    "taskType":"offer-notification"
}'

---

Producer

Producer 1

Name : Greeter-Service

Start Greeter-Service.

APP_NAME=Greeter PORT=3000 yarn start

Use Greeter-Service to schedule a greet task type to send new-year wishes to customers based on their time zones.

curl --location --request POST 'http://localhost:3000/schedule' \
--header 'Content-Type: application/json' \
--data-raw '{
    "taskType":"greet",
    "payload":"Send new-year wishes to all customers in the UTC 5.30 timezone.",
    "timeInMillis":2500
}'

• Conisder "timeInMillis":2500 is a time-offset from user current timezone.

curl --location --request POST 'http://localhost:3000/schedule' \
--header 'Content-Type: application/json' \
--data-raw '{
    "taskType":"greet",
    "payload":"Send new-year wishes to all customers in the UTC 5.00 timezone.",
    "timeInMillis":2000
}'

Producer 2

Name : Offer-Notification-Service

Start Offer-Notification-Service.

APP_NAME=Offer-Notification PORT=3001 yarn start

Use Offer-Notification-Service to schedule an offer-notification task type to send black Friday offer details early to premium customers.

curl --location --request POST 'http://localhost:3001/schedule' \
--header 'Content-Type: application/json' \
--data-raw '{
    "taskType":"offer-notification",
    "payload":"Send black-friday offer details at midnight to premium customers",
    "timeInMillis":1500

}'

Use Offer-Notification-Service to schedule an offer-notification task type to send black Friday offer details at morning to non-premium customers.

curl --location --request POST 'http://localhost:3001/schedule' \
--header 'Content-Type: application/json' \
--data-raw '{
    "taskType":"offer-notification",
    "payload":"Send black-friday offer details at morning to non-premium customers",
    "timeInMillis":3500

}'

• The schedule api will return the task id, which can be used to invalidate the task if required.

---

Invalidate scheduled task

curl --location --request POST 'http://localhost:3000/invalidateTask' \
--header 'Content-Type: application/json' \
--data-raw '{
    "taskId": "taskId"
}'

Demo

Task-Scheduler-Demo-Compressed.mp4