QUARKUS-DEMO.md

Demo scenario

• Introduce speakers and purpose of the talk: Migration of applications
  • Agenda

    • OpenRewrite: Migration Swiss knife toolbox

      • Huge collection of recipes = java classes executed through visitor pattern
      • Can be used to transform OR analyze
      • Support "dryrun" or "run" mode
      • Executed using "maven" BUT
      • Slow when several "mvn" cmds should be executed,
      • No easy way to design: unit test
      • No API or Library

    • Quarkus Rewrite Client

      • Client and Library designed around OpenRewrite
      • Bypass most of the limitations described previously
      • To use it, compile it locally or install it using jbang

        mvn clean install -DskipTests -Dquarkus.package.type=uber-jar
        jbang app install --force --catalog jbang-catalog-dev.json openrewrite

      • Demo 1

        pushd test-project/simple
        openrewrite . -r org.openrewrite.java.format.AutoFormat
        openrewrite . -r org.openrewrite.java.format.AutoFormat -d false
        openrewrite . -c rewrite.yml
        popd
        
        or
        
        openrewrite test-project/simple -c rewrite.yml

      • Demo 2

        Show some Test cases

    • What about Migrating Applications

      • OpenRewrite tool => perfect to execute YAML recipes
      • Scenario could be really complex even when want to migrate some REST annotations
      • Demo 3

      pushd rewrite-client/test-project/quarkus-resteasy-classic-app
      openrewrite . -c rewrite.yml

      • YAML format is quite verbose, users will make errors, etc
      • Users should be educated, trained and ideally supported by a migration tool

    • Present the mtool project

      • Quarkus Client able to analyze, generate a migration plan and transform
      • Demo 4
        • Present a migration scenario: Spring Boot Todo to Quarkus Todo
        • Show 1-2 rules => preconditions and when condition
        • Life becomes easier as Antlr can parse/process the Query
        • Run analysis and detail the console's table

          mtool analyze ./applications/spring-boot-todo-app -r ./cookbook/rules/quarkus-spring-precondition
          mtool analyze ./applications/spring-boot-todo-app -r ./cookbook/rules/quarkus-spring

          A report = migration plan has been generated packaging instructions :-)
        • Show that the SB Todo app is working

          mvn clean package spring-boot:run
          firefox localhost:8081

        • Do the transformation/migration using as provider "Openrewrite" => dryrun

          mtool transform ./applications/spring-boot-todo-app -p openrewrite --dry-run
          // Show patch files generated !
          mtool transform ./applications/spring-boot-todo-app -p openrewrite

          • Launch Quarkus Todo

          mvn clean package -DskipTests quarkus:dev
          firefox http://localhost:8080/q/dev-ui/extensions
          
          // Curl
          curl http://127.0.0.1:8080/home
          curl -X POST http://localhost:8080/home \
          -H "Content-Type: application/json" \
          -d '{
          "title": "Prepare migration to Quarkus. Task 1",
          "description": "Migrating Spring Boot TO DO to Quarkus. Task 1",
          "dueDate": "2025-12-24"
          }'
          
          curl -X POST http://localhost:8080/home \
          -H "Content-Type: application/json" \
          -d '{
          "title": "Prepare migration to Quarkus. Task 2",
          "description": "Migrating Spring Boot TO DO to Quarkus. Task 2",
          "dueDate": "2025-12-24"
          }'

      • What else: when we reach the limit of openrewrite or that no recipes => use AI
      • Demo 5

        run the video

    • Wrap-up and Q/A