App that allows to schedule message processing for some predefined delay. Main idea is based on https://redislabs.com/ebook/part-2-core-concepts/chapter-6-application-components-in-redis/6-4-task-queues/6-4-2-delayed-tasks/ and just wrapped with some Netty code. This is not-production ready (honestly it is nothing-ready) but shows how you can process delayed-messaged in very gently manner.
Prepare Redis instance on default port 6379 (and localhost of course) and invoke (to build and start).
./gradlew buildApp
java -jar ./build/libs/scheduler-server-1.0-SNAPSHOT.jar
Then just make a curl to schedule message.
curl --request PUT \
--url http://localhost:8080/messages/someId \
--header 'content-type: application/json' \
--data '{
"when" : "2007-12-03T10:15:30.00Z",
"event" : {
"message" : "hello"
}
}'Also, if you prefer to use your browser, Swagger console is available on port 8080.
Because looking at logs is not best option to show how something works - you can subscribe on all incoming delayed events:
curl --raw 127.0.0.1:9090/subscribe -v -k
as response, you will receive all events received from delay-queue application (this endpoint is chunked).
Entire stuff that is responsible for handling this endpoint and delay-messages consumption is stored under "example" package
from time to time it is good to try to kill your application (which you are actually developing), if you want to do that with delay-queue, I prepared command line for you (I used wrk)
./wrk -t14 -c300 -d400 -s ./redis.lua http://localhost:8080/messages
where redis.lua is
wrk.method = "POST"
wrk.body = "{\"when\" : \"2018-12-28T21:58:00.00Z\",\"event\" : {\"message\" : \"hello\"}}"
happy shooting !