yus

How to start the yus application

1. Run mvn clean install to build your application
2. Start application with java -jar target/inmem-admin-1.0-SNAPSHOT.jar server config.yml
3. To check that your application is running enter url http://localhost:8080

Health Check

To see your applications health enter url http://localhost:8081/healthcheck

Notes While Doing My Thing

Wanted to quickly test how to use the Admin endpoints to do some lightweight storage in-memory. Read through Dropwizard and knew about healthchecks. Was less familiar with how Tasks work.

Seems like they are similar but with Tasks, we have some more flexibility from a first glance. I'm experimenting with Tasks.

Built a starter DW using archetype. Then followed instructions to set up a simple task.

I opted to set up a PostBodyTask because I think that will provide the most flexibility.

I also did a bit of source code reading to understand the default TaskServlet in the AdminEnvironment setup. One interesting thing is that by default it will return only text/plain;charset=utf-8 content. I can live with that for my use case, but it seems possible to customize this to one's needs with a bit more source code exploration.

I immediately found I was having problems getting the PostBody that I was sending in my simple curl request to go through. The parameter meant for the POST body was always empty.

curl -XPOST localhost:8081/tasks/flag -d "woooop" -v

Turns out an unspoken rule is that by default, Content-Type: application/x-www-form-urlencoded data is passed to the first parameter. Which I think is actually common, but something I often forget about since they both appear to use POST request method.

When I changed to application/json, I had more success accessing the post body parameter.

Either approach can work depending on your needs.

curl -XPOST localhost:8081/tasks/flag -d "woooop" -v -H "Content-Type: application/json"

The final step was to make a proof of concept which this repo does. For the life of the application, the static variable serves as an in-memory storage of some administrative values that we care about.

# Get the flags, will return empty string body
curl -v -XPOST localhost:8081/tasks/flag

# Set the flags, will set and return the flags.
curl -v -H "Content-Type: application/json" -XPOST localhost:8081/tasks/flag?action=set -d "yusuphisms" 

# Get the flags, subsequent calls will return the last value set for the static member for the life of the application
curl -v -XPOST localhost:8081/tasks/flag

Generally happy with this smol proof of concept.