CRaC Name service

This is a little demo name service. It will lazy load around 280000 names from a json file into memory the first time you call it. That means the first time you call the service it will take a bit longer to get the response because it will first load the files into memory. Keep in mind that this is only to demonstrate CRaC, usually you won't do lazy loading at the first call. The service will return a json reponse with the names and it will also give you the time it took to return the response. Starting it without CRaC will show that the first call takes longer. When using CRaC, the service will be warmed up before the checkpoint will be created. In the Micronaut CRaC module you can define a specific warmup script which will be called to warm up the service. In this case it will simply curl the service to make sure it is warmed up. After the script ran, a checkpoint will be created and will be stored in the docker image. With the checkpoint in the docker image the service will start up and it will be already warmed up which means the first time to response will be fast because the names already have been loaded.

Start the application with ./gradlew run

Open a browser and type in http://localhost:8080/names?gender=female&amount=10

You should see 10 random female names in JSON format in your browser and also the time it took to create the response.

Run without CRaC

Execute ./gradlew run

Execute curl "localhost:8080/names?gender=female&amount=5"

The result should show something like this for the first response without CRaC:

{
  "names":[
    {
      "first_name":"Birtha",
      "gender":"female"
    },
    {
      "first_name":"Dorothea",
      "gender":"female"
    },
    {
      "first_name":"Eva",
      "gender":"female"
    },
    {
      "first_name":"Lynnette",
      "gender":"female"
    },
    {
      "first_name":"Missy",
      "gender":"female"
    }
  ],
  "response_time":"931 ms"
}

This is for the first response only and you see that the response time in this case was 931 ms.

Run with CRaC

Build docker image

Execute ./gradlew dockerBuildCrac to create a docker image containing a CRaC enabled JDK and a pre-warmed, checkpointed application.

Execute bash start.sh

Execute curl "localhost:8080/names?gender=female&amount=5"

The result should show something like this for the first response with CRaC:

{
  "names":[
    {
      "first_name":"Berta",
      "gender":"female"
    },
    {
      "first_name":"Doris",
      "gender":"female"
    },
    {
      "first_name":"Emma",
      "gender":"female"
    },
    {
      "first_name":"Lisa",
      "gender":"female"
    },
    {
      "first_name":"Melanie",
      "gender":"female"
    }
  ],
  "response_time":"21 ms"
}

This is for the first response only and you see that the response time in this case was 21 ms, which is way faster because the application was already "warmed up". Here the warm up is mainly loading the names from the json file into memory.