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Devoxx : being productive with JHipster


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Slides from the "being productive with JHipster" talk at Devoxx Belgium 2016 by Julien Dubois (JHipster lead) & Deepu K Sasidharan (JHipster co-lead).

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Code commited (live!) during the presentation is at:

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Devoxx : being productive with JHipster

  1. 1. Being productive with JHipster Julien Dubois & Deepu K Sasidharan 1
  2. 2. Who we are ● Julien Dubois ○ JHipster creator & lead developer ○ Chief Innovation Officer at Ippon Technologies ● Deepu K Sasidharan ○ JHipster co-lead ○ Product developer at XebiaLabs 2
  3. 3. React to the talk! ● Mention @java_hipster ● We’ll do our best to answer you during the talk! 3J
  4. 4. Introduction to JHipster ● Spring Boot + AngularJS application generator ● Fully Open Source ● +250 contributors ● +5300 Github stars ● +320,000 installations ● +100 companies officially using it 4D
  5. 5. Server side frameworks 5J
  6. 6. Client side frameworks 6D
  7. 7. Section I Installation & Application Generation 7
  8. 8. Installation ● Installation with NPM ● Alternative installations: Docker, JHipster Devbox > npm install -g generator-jhipster@3.9.1 8D
  9. 9. oh-my-zsh ● oh-my-zsh is a framework for managing your ZSH configuration ○ ● Specific JHipster plugin ○ Also recommended: git, docker and docker-compose plugins > jh 9J
  10. 10. Creating an application ● Questions & answers to generate an application tailored to your needs ● Questions depend on the previous answers ● Validation & help to avoid mistakes > mkdir myapp && cd myapp > yo jhipster 10D
  11. 11. IDE configuration ● Intellij IDEA, Eclipse, Netbeans ○ Specific “IDE” profile for MapStruct ● Visual Studio Code ○ Usage with Maven/Gradle or JHipster App > idea . 11J
  12. 12. What has been generated? ● Spring Boot application ● AngularJS application ● Liquibase changelog files ● Configuration files 12D
  13. 13. The generated screens: security ● Several generated screens ○ Login, logout, forgot password… ○ Account management ○ User management ● Useful for most applications ○ Pages must be tuned depending on business needs ○ User roles will be added/extended ● Provide also good examples of working screens ○ Forms, directives, validation... 13J
  14. 14. The generated screens: administration ● Administration screens ○ Monitoring ○ Health ○ Spring Boot configuration ○ Spring Security audits ○ Log management ● Very useful in production ● Will probably be a separate module in JHipster 4 14D
  15. 15. Maven / Gradle usage ● Maven/Gradle wrappers ● Available goals: clean, compile, run, test... ● Specific profiles: “dev” and “prod” > ./mvnw clean test 15J
  16. 16. Docker and Docker Compose ● JHipster generates full Docker & Docker Compose configuration ○ Build an image for the current application ○ Launch services: MySQL, Elasticsearch, Kafka... ○ Sonar ● Very useful in development, and for microservices > docker-compose -f src/main/docker/mysql.yml up -d 16D
  17. 17. SQL Database support ● Can use different development & production databases ● H2 disk-based and in-memory ● Supported databases: MySQL, MariaDB, PostgreSQL, Oracle ● Spring Data JPA ● HikariCP 17J
  18. 18. Liquibase ● Liquibase manages database updates ○ Using changelogs ● Great for working in team ○ After a “git pull”, your database is always up-to-date! ● Tables, relationships, data are all created by JHipster at generation time, and applied when the application starts 18D
  19. 19. Hibernate 2nd level cache ● 3 options ○ No cache ○ Ehcache ■ Default for monoliths ■ Upgrade soon to Ehcache 3 ○ Hazelcast ■ Default for microservices, with a specific configuration for clustering ● Automatically monitored ○ Production defaults are low, should be tuned depending on your business/hardware 19D
  20. 20. MongoDB ● Alternative to SQL databases ● Faster startup, works great for cloud applications ● Spring Data MongoDB ● Changelogs are managed by Mongobee 20J
  21. 21. Cassandra ● Another alternative to SQL databases ● Custom implementation using the DataStax Java Driver ● Custom changelog implementation ● Spring Boot Cassandra support comes from JHipster! 21J
  22. 22. Elasticsearch ● Optional add-on to the other options ○ Very popular ● Use Spring Data Elasticsearch ● Add server-side and client-side code for searching entities ● Uses by default an embedded server in development, we recommend the Docker image for faster turnaround 22D
  23. 23. Kafka ● Optional add-on ○ For handling very large amount of events ○ Some people use it to handle load and failover with microservices ● Use Spring Cloud Stream ● Simple integration for the moment 23J
  24. 24. Security ● Session-based authentication ○ Stateful ○ Classical “form-based” authentication with Spring Security ○ Improved remember-me over the standard Spring Security implementation ● OAuth2 ○ Stateless ○ Needs a specific back-end, only works with SQL and MongoDB ● JWT ○ Stateless ○ Very good for microservices 24D
  25. 25. Internationalization ● i18n is managed by Angular Translate on the client-side ● “normal” Java i18n is used on the server-side ● 26 langages out-of-the-box, easy to extend 25J
  26. 26. Swagger ● Automatic documentation for all REST APIs ● Executable and easy-to-use ● Great for AngularJS developers (no need to read the Spring MVC REST code!) 26D
  27. 27. WebSockets ● Optional add-on ● Uses Spring WebSockets ○ Easy to integrate ○ Hard to scale on several nodes ● Sample generated screen to track users live ○ Tracks who is logged in, their current screen, all in real time 27J
  28. 28. Creating an entity ● The entity sub-generator is our more complete and more popular sub-generator ● Creates an entity, with full CRUD support ○ Liquibase changelog ○ Spring Data JPA repository ○ Spring MVC REST endpoint ○ AngularJS router/controller/service/view ○ i18n ○ Tests ● Tip: use Git to save your work before/after running a sub-generator! 28D
  29. 29. Creating fields ● Fields are created one after the other ● Lots of types are available ○ Types depend on the underlying database (SQL/MongoDB/Cassandra) ● Validation is available ○ AngularJS validation on the client side ○ Bean validation used by Spring MVC REST and Hibernate ○ Database constraints 29J
  30. 30. Managing relationships ● Relationships only work for SQL databases ● All JPA relationship types are supported ○ one-to-one, many-to-one, one-to-many, many-to-many ● Unidirectional and bidirectional relationships ● Multiple relationships on the same 2 entities 30D
  31. 31. The “User” entity ● Specific entity, generated with the core application ○ Used by Spring Security ○ Can be extended ● Supports many-to-one, many-to-many (non owner side) and one-to-one (non owner side) relationships ● Tip: some people do a one-to-one relationship to a specific “CustomUser” entity, which they modify/extend (modifying the User entity can cause issues when upgrading the application) 31J
  32. 32. Using DTOs ● DTOs = Data Transfer Objects ● Very useful in business applications, where basic CRUD entities are not enough ○ Add business logic ○ Separate the view layer from the persistence layer ○ Helps with lazy-loading ● Uses MapStruct to generate the mapping ○ Java annotation processor 32D
  33. 33. Using a service layer ● Very useful in business applications, where basic CRUD entities are not enough ○ Like DTOs ○ Usually both options are selected at the same time, but it depends on what you want to do ● Service beans are Spring beans: security, transactions, monitoring are available ● Option to use just an implementation, or an interface + an implementation 33J
  34. 34. Pagination options ● 3 pagination options are available: ○ Simple pager ○ Pagination links ○ Infinite scroll ● Depends on your business needs and database capabilities (Cassandra can’t do pagination links) ● Very useful if you have data (all situations except reference tables) ○ Common pitfall is to do Gatling tests on non-paginated entities 34D
  35. 35. Re-generating an entity ● The entity sub-generator can re-generate an existing entity ○ Just call it again with the entity name ○ Fields and relationships can be removed/added ● Tip: advanced users modify directly the .jhipster/*.json files ○ Internal JHipster configuration files ○ In fact just the answers serialized in JSON - easy to understand and modify if needed 35J
  36. 36. Upgrading an application ● Upgrades can be done automatically with the Upgrade sub-generator ● Use Git branches to generate the application with a different version ● Automatic merge if there is no problem ● Conflicts must be resolved manually > npm install -g generator-jhipster@3.10.0 > yo jhipster:upgrade 36D
  37. 37. Section II Working with the Generated Application 37
  38. 38. Setting up a good development environment ● “Developer Experience” is very important for JHipster ○ Lots of effort to make your development environment great ● Hot reload should work everywhere ● IDEs should work automatically ● Docker Compose for all 3rd-party tools, so they are easy to manage 38J
  39. 39. Spring Boot devtools ● Automatically reloads the application when a compilation occurs ○ The application classloader gets refreshed ○ The JVM and third-party libraries are not refreshed ● Hot reload is very quick: 2 to 4 seconds depending on your setup ● Liquibase being managed by JHipster, the database schema is also automatically updated ● Tip: configure your IDE to do automatic compilation, and everything is updated automatically! 39D
  40. 40. Spring Data JPA ● Easily generate SQL requests from Java method names ○ List<Product> findByOrderByName() ○ List<Item> findByUser(User user) ○ List<Customer> findByLastName(String lastName) ● Tip: type the method name in the REST controller that uses it, and then use your IDE to automatically generate the method 40J
  41. 41. Fluent methods in JPA entities ● JPA entities generated by JHipster have fluent methods ● Allows to chain method calls on entities Post post = new Post() .title("Fluent methods are cool!") .createdOn( .addPostComment(postComment); 41J
  42. 42. Liquibase ● Changelogs are generated by JHipster, and can also be hand-coded ● Another solution is to use the Maven “liquibase:diff” goal ○ Modify the JPA code ○ Compile the application ○ Run “./mvnw liquibase:diff” ○ This will generate a changelog to update your database schema ○ Add the resulting changelog to the master changelog ● Changelogs are applied at application start-up (also works with Spring Boot hot reload) 42D
  43. 43. Gulp & BrowserSync ● Gulp allows to run many JavaScript tasks: minification, injection, tests… ● One of its main usage with JHipster is to run BrowserSync ● BrowserSync has 2 great features ○ Synchronizes clicks, scrolls and inputs on different browsers: great for testing with several screen resolutions! ○ Reloads the browser(s) when a file changes: great for doing web application development! ● Tip: combined with Spring Boot devtools and Liquibase, a correct JHipster development environment should have everything hot reloaded automatically! 43J
  44. 44. Bower ● Installation and update of JavaScript/CSS libraries for the client-side application ● If BrowserSync runs in the background, libraries are automatically injected in the index.html page (otherwise, do a “gulp inject” to force the injection) ● Tip: in JHipster 4.0, Bower should disappear, and will be totally replaced by NPM > bower install bootstrap-material-design#0.3.0 --save 44D
  45. 45. Profiles ● JHipster manages profiles both at runtime (Spring profiles) and at build time (Maven/Gradle profiles) ● 2 main profiles ○ “dev” for development: focuses on great Developer Experience ○ “prod” for production: focuses on the best performance for production ● Other profiles are for specific situations ○ “swagger” Spring profile to enable/disable Swagger ○ “no-liquibase” Spring profile to disable liquibase ○ “ide” Maven profile to help configuring the IDE (for MapStruct usage) 45J
  46. 46. Working with AngularJS ● JHipster follows the John Papa style guide ○ Official guide, endorsed by the AngularJS team ○ Lots of rules and best practices, clearly explained ○ Gives a migration path to AngularJS 2 ● JHipster uses a few third-party libraries ○ UI Router for routing ○ Twitter Bootstrap ○ Datepicker, infinite scrolling ● All other libraries are supposed to be installed easily through Bower 46D
  47. 47. A word on Angular 2 ● Angular 2 support is coming soon in JHipster! ○ Work is 90% ready on the main generator ○ The entity sub-generator is not migrated yet ○ We will have a new option to generate either an AngularJS 1 or an Angular 2 project ○ Both options will live next to each other ○ Focus will shift to Angular 2 as more projects adopt it, and as it becomes more stable ● This will be the main focus of JHipster 4.0 47D
  48. 48. Customizing Bootstrap ● JHipster uses the “standard” Twitter Bootstrap classes ● They can be overridden as usual ○ Update the main.css file if using CSS ○ Update the main.scss if using Sass ● It’s also easy to install a specific theme (often automatic just using Bower) ● Bootstrap 4 support is coming in JHipster 4.0 48J
  49. 49. Section III Testing the Generated Application 49
  50. 50. Spring integration tests ● JHipster provides JUnit and Spring integration test support ○ Integration tests are fast as the Spring context and the database are re-used over each test ○ Mockito is used to mock dependencies ○ @WithMockUser from Spring Security is great ○ Yes, using field injection with Spring is annoying for tests! ● The entity sub-generator generates specific tests for each CRUD operation 50J
  51. 51. Karma.js ● Unit tests are generated for the main application and for the entities ○ Uses mock to simulate the back-end 51D
  52. 52. Gatling ● Available as an option ● Generate load testing simulations for CRUD entities ○ Uses the 4 CRUD methods ○ Must be tuned depending on your real business needs ○ Generates a great dashboard ○ Don’t forget to use pagination! ● Gatling tests can be run directly from Maven ● Simulations are developed with a Scala DSL ○ Not very complex to use ○ Scala compilation is slow at startup! 52J
  53. 53. Cucumber ● Available as an option ● Behavior-driven tests becoming more and more popular ● Simple integration at the moment ○ Might not evolve as we can’t generate business code 53D
  54. 54. Protractor ● Great way to do integration testing with AngularJS ○ End-to-end test of the application ○ Needs a fully working back-end server ○ Uses by default a Firefox browser, which often leads to issues 54J
  55. 55. Code quality with Sonar ● Sonar gives a complete quality report of the application ○ Java and Spring code ○ JavaScript code ● JHipster provides a Docker Compose configuration with a fully working Sonar server > docker-compose -f src/main/docker/sonar.yml up -d > ./mvnw clean test sonar:sonar 55J
  56. 56. Continuous integration ● Travis configuration is generated ○ Full test of both the back-end and the front-end ○ Similar to what the JHipster team uses to test the generator itself! ● Jenkins 2 configuration is generated ○ With complete documentation on the JHipster website for Jenkins 1 and 2 56D
  57. 57. Section IV Going to Production 57
  58. 58. JHipster production build ● Generates an executable WAR file with production options ○ Minified front-end ○ GZip filter ○ HTTP cache headers > ./mvnw clean package -Pprod > docker-compose -f src/main/docker/mysql.yml up -d > cd target > ./myapplication-0.0.1-SNAPSHOT.war 58J
  59. 59. Monitoring JHipster ● Standard Spring Boot Actuator endpoints are available ○ With a UI! ● Dropwizard Metrics is configured ○ JVM & HTTP request metrics ○ Spring Beans metrics ○ Ehcache metrics ● Logs can be sent to an ELK server ○ More about the JHipster Console in the “microservices” section 59D
  60. 60. Building a Docker image ● Full Docker configuration has been generated in the src/main/docker folder ○ A Dockerfile ○ A Docker Compose configuration with the application and its dependencies ● The Docker daemon must be running when the Docker image is built > ./mvnw package -Pprod docker:build > docker-compose -f src/main/docker/app.yml up 60J
  61. 61. The Docker Compose sub-generator ● Works for both monoliths and microservices ● Allows for more complex setups than the default Docker Compose file ○ Adding monitoring with the JHipster Console ○ Mostly useful for microservices 61J
  62. 62. Docker Compose & Docker Swarm ● Docker Compose applications can be deployed to Docker Swarm cluster ○ Having a production-grade Docker Swarm cluster is very hard ○ Deploying to a cluster is similar as deploying locally ● Applications launched in a cluster can be scaled ○ Works out-of-the-box for microservices ○ A gateway/load balancer is necessary to handle port conflicts ○ Hibernate 2nd level cache must be disabled, or distributed > docker-compose -f src/main/docker/app.yml scale myapplication-app=3 62D
  63. 63. Deploying on Kubernetes ● Kubernetes sub-generator is in BETA ○ Developed by Ray Tsang (@saturnism) from Google ○ Similar to the Docker Swarm sub-generator > yo jhipster:kubernetes 63J
  64. 64. Deploying to Cloud Foundry ● Specific sub-generator to deploy to Cloud Foundry ● Uses the “cf” command-line to deploy the application, bind a database service, etc. ○ Can only support services available on your Cloud Foundry marketplace > yo jhipster:cloudfoundry 64D
  65. 65. Deploying to Heroku ● Specific sub-generator to deploy to Heroku ○ Developed by Joe Kutner from Heroku ● Uses the “heroku” command-line to deploy the application, bind a database service, etc. > yo jhipster:heroku 65J
  66. 66. Other deployment platforms ● AWS ● BoxFuse ● Application servers ● Executable WAR 66D
  67. 67. Section V Tooling & sub-projects 67
  68. 68. JDL ● JHipster Domain Language ● Makes generating complex entity models easily ● Supports all entity sub-generator features ○ Field types ○ Validation ○ Relationships ○ DTOs ○ Service ○ Enumerations ○ ... 68J
  69. 69. JDL Studio ● Open Source Web application ○ Available at ● Auto-completion and validation ● Sublime Text keymap ● Graphical view ● Share as URL ● Import/export models 69D
  70. 70. JHipster IDE ● IDE support for JDL ○ Eclipse, IDEA, Visual Studio Code ○ Still in Beta 70J
  71. 71. Modules ● JHipster modules gives all the power of JHipster sub-generator to everyone ○ Modules are independent from JHipster ○ Modules are Yeoman generators, using the JHipster public API ○ Release when you want, use the license you want… ● If you want your module to be public, you can publish it on the JHipster marketplace ○ Available at ○ 24 modules available today ○ Free for everyone, as always with JHipster! 71D
  72. 72. Section VI Microservices 72
  73. 73. Microservices architecture ● JHipster provides a full microservice architecture ● Gateway(s) to give access to the microservice architecture ○ Based on Netflix Zuul ● Registry to find services ○ JHipster Registry (based on Netflix Eureka) or Hashicorp Consul ● Microservices ● Security ● Monitoring ● Scaling 73J
  74. 74. Microservices architecture 74J
  75. 75. Gateway(s) ● Gateways are normal JHipster applications ○ Full JHipster capabilities ● Provide access to the microservices ○ Using Netflix Zuul for routing, load balancing, failover ○ Provide security using JWT or OAuth2 ○ Provide quality of service using a custom Zuul filter + Cassandra ○ Provide full Swagger documentation for both the gateway and the microservices ● Tip: you can have several gateways, specialized on your business needs 75D
  76. 76. Microservices ● Microservices are normal JHipster applications, without the AngularJS front-end ● All database combinations, Elasticsearch and other options are available ● The JDL Studio can also be used to generate the CRUD entities ● Main limit is that Websockets are not available ○ Will change with Zuul 2 76J
  77. 77. JHipster Registry ● JHipster Registry is an Open Source application developed specifically for the JHipster microservices architecture ○ Uses Netflix Eureka for service registration/discovery ○ Uses Spring Cloud Config to push Spring Boot configuration to microservices ■ Very useful for pushing secrets (like database passwords) ■ Can re-configure microservices ■ Configurations can be stored in Git, allowing to version/tag them easily ○ Has an easy-to-use Web interface (built with JHipster!) ○ Is available pre-built as a Docker image on the Docker Hub 77D
  78. 78. HashiCorp Consul ● Alternative to the JHipster Registry ○ Focus on consistency (while Eureka focuses on availability) ● More efficient than Eureka on many points ○ Faster service registration/un-registration ○ Smaller footprint ○ DNS server included ○ UI included ● But the JHipster Registry is more stable, is easier to extend (it’s a JHipster application) and has better Spring Cloud Config support 78J
  79. 79. JHipster Console ● Monitoring application built with ELK (Elasticsearch Logstash Kibana) ● Optimized for JHipster ○ Receives directly events from JHipster over a socket, with the correct format ○ Has pre-configured dashboards for JHipster ● Can be automatically set up with the Docker Compose sub-generator ● Available pre-built as a Docker image on the Docker Hub 79D
  80. 80. Customizing Netflix Zuul ● Gateways use Netflix Zuul to provide routing, load balancing and failover ● Netflix Zuul can be customized using filters ○ JHipster provides pre-built filters, for example for quality of service ● New filters can be added depending on your business needs 80J
  81. 81. Generating entities with microservices ● Entities can be generated for microservices, like any JHipster application ○ Only the back-end code is generated (no AngularJS client code is generated) ○ All usual options are available ○ The JDL Studio can be used as usual ● For Gateway(s), entities can also be generated from microservices ○ The front-end is generated on the gateway, and connect through Netflix Zuul to the microservice back-end ○ Front-end applications can gather entities from several microservices, as well as from entities from the gateway itself 81D
  82. 82. Hazelcast distributed cache for microservices ● Hazelcast is the default Hibernate 2nd level cache for entities generated on microservices ● JHipster generates specific configuration, using the JHipster Registry, so that different instances of the same microservice join each other in the same distributed cache ● Distributed cache with Hazelcast will work automatically with Docker Swarm, when a microservice is scaled > docker-compose scale mymicroservice-app=3 82J
  83. 83. Security for microservices ● Default security is JWT ○ The JWT token is generated by the gateway ○ All microservices accept the token, as they share a secret key with the gateway ○ This secret key is sent to all gateway(s) and microservices by the JHipster Registry, using Spring Cloud Config ● Beta option to support OAuth2 ○ Using the JHipster UAA server 83D
  84. 84. Deploying and scaling on Docker Swarm ● Same as deploying on a local Docker, but on a full cluster! ● Main difference is that we can scale microservices ○ This is why distributed cache and JWT are important > docker-compose up -d > docker-compose scale mymicroservice-app=3 84J
  85. 85. Deploying and scaling on Kubernetes ● Basically the same as Docker Swarm, but on Kubernetes ○ Works on Google Cloud Platform ○ Still in Beta > kubectl apply -f myapplication > kubectl scale --replicas=3 jhipster/myapplication 85D
  86. 86. Section VII Getting help 86
  87. 87. Community help ● #1 rule: everything is public ● Questions are on StackOverflow with the “jhipster” tag ● Bugs & feature requests are on our GitHub issue tracker ● Please follow our contributing guidelines if you want help! 87J
  88. 88. Questions? Answers! 88