This document discusses Dropwizard, a microservices framework for Java. It provides an introduction to Dropwizard and microservice architecture. Key points include: Dropwizard allows developing applications as suites of small services that communicate via HTTP APIs; it provides libraries for configuration, metrics, logging, and health checks; and projects using Dropwizard are packaged into single JAR files for easy deployment. The document outlines how to structure a Dropwizard project and develop microservices using its various components.

1. #JCConf
Dropwizard
-微服務架構框架-
anthonychen

2. #JCConf
About anthonychen
Github: https://github.com/anthonych
Blog: http://blog.anthonychen.idv.tw
Twitter: https://twitter.com/anthonychen

3. #JCConf
Agenda
• Dropwizard Introduction
• Microservice Architecture
• Why Dropwizard
• How to Dropwizard
• More Dropwizard

4. 有一天…

5. 於是...

6. 本來我以為是...

7. 結果其實是...

8. 其實我需要的只是...

9. 發現 Dropwizard!

10. 2011.12 Opened by Yammer

11. Drop...wizard?
http://gunshowcomic.com/316

12. mustache
Dropwizard 包括...
Microservice Framework

13. dropwizard-assets dropwizard-jackson dropwizard-migrations
dropwizard-auth dropwizard-jdbi dropwizard-servlets
dropwizard-client dropwizard-jersey dropwizard-spdy
dropwizard-configuration dropwizard-jetty dropwizard-testing
dropwizard-core dropwizard-lifecycle dropwizard-util
dropwizard-db dropwizard-logging dropwizard-validation
dropwizard-example dropwizard-metrics-ganglial dropwizard-views-freemarker
dropwizard-forms dropwizard-metrics-graphite dropwizard-views-mustache
dropwizard-hibernate dropwizard-metrics dropwizard-views
Dropwizard Modules (v0.7.1)

14. Microservice Architecture
The microservice architectural style is an approach to developing
a single application as a suite of small services, each running in
its own process and communicating with lightweight
mechanisms, often an HTTP resource API. These services are
built around business capabilities and independently deployable
by fully automated deployment machinery.
- Martin Fowler
http://martinfowler.com/articles/microservices.html
http://martinfowler.com/articles/microservices.html

15. pid 1234 8GB heap
Monolithic Micro Services
pid 5978
2GB heap
pid 1234
2GB heap
pid 5678
2GB heap
pid 9527
2GB heap
Architecture

16. Monolithic Micro Services
Scalability

17. P
R
O
X
Y
Extensibility

18. Project Management

19. Microservice vs. SOA...
VS.

20. SleepyA RESTful framework for Go
Microservice Frameworks

21. Why
DropWizard?

22. http://www.oracle.com/us/technologies/java/gimmejava/usage-terms/index.html

23. 開發效率

24. 容易佈署
Single JAR

25. Self-Contained

26. http://www.techempower.com/benchmarks/#section=data-r9&hw=i7&test=json&f=311c-1hq8-0-0

27. http://www.techempower.com/benchmarks/#section=data-r9&hw=i7&test=db&f=311c-1hq8-0-0

28. http://www.techempower.com/benchmarks/#section=data-r9&hw=i7&test=query&f=311c-1hq8-0-0

29. How to
DropWizard?

30. 自 Dropwizard 0.7版開始，Service 類別改名為 Application
開發流程
Configuration
• YAML 設定檔
• Configuration 類別
Domain
• JDBI, Hibernate
• POJO 類別
• 可以是 hibernate entity
Resource
• Jersey controller 類別
• RESTful API 方法
Health Check
• 自訂 Healcheck 類別
• Freemarker, Mustache
Application
• 程式啟動點
• 設定 Resource, Healcheck...
Configuration Domain/DAOs Resource
Healthcheck/View Application
Build & Run

31. project-api: API 格式類別，通常是 JSON
project-client: API 的 HTTP客戶端程式
project-application: 應用程式實作
模組架構

32. com.example.myapplication:
api: API 格式類別實作
cli: Command 類別
client: HTTP 客戶端實作
core: Domain 類別實作
jdbi: JDBI 資料庫存取相關實作
health: Health Check 類別實作
resources: Resource 類別實作
Dropwizard 專案結構

33. server:
type:simple
applicationContextPath:/application
adminContextPath:/admin
database:
driverClass:com.mysql.jdbc.Driver
user:anthonychen
password:anthonychen
url:jdbc:mysql://localhost:3306/demo
Configuration Reference: http://dropwizard.io/manual/configuration.html
Configuration 檔案 (YAML)

34. public class BlogConfiguration extends Configuration {
@Valid
@NotNull
@JsonProperty("database")
private DataSourceFactory database = new DataSourceFactory();
public DataSourceFactory getDatabase() {
return database;
}}
Configuration 類別

35. public class DatabaseHealthCheck extends HealthCheck {
private final Database database;
public DatabaseHealthCheck(Database database) {
this.database = database;
}
@Override
protected Result check() throws Exception {
if (database.isConnected()) {
return Result.healthy();
} else {
return Result.unhealthy("Cannot connect to " + database.getUrl());
}
}}
Health Check 類別

36. ViewBundle
AssetsBundle
HibernateBundle,
ScanningHibernateBundle
MigrationsBundle
客製自己的Bundle – 實作ConfiguredBundle 介面
Bundle 類別

37. public class BlogApplication extends Application<BlogConfiguration> {
public static void main(String[] args) throws Exception {
new BlogApplication().run(args);
}
@Override
public void initialize(Bootstrap<BlogConfiguration> bootstrap) {
bootstrap.addBundle(hibernateBundle);
bootstrap.addBundle(new ViewBundle());
bootstrap.addBundle(new AssetsBundle("/assets/js", "/js", null, "js"));
}}
註冊 Bundles
Application 類別 – initialize( )

38. @Override
public void run(BlogConfiguration configuration, Environment environment) throws Exception {
// Crete DAOs
final ArticleDAO articleDAO = new ArticleDAO(hibernateBundle.getSessionFactory());
final UserDAO userDAO = new UserDAO(hibernateBundle.getSessionFactory());
// Create healthchecks
final SessionFactoryHealthCheck dbHealthCheck = new SessionFactoryHealthCheck(
hibernateBundle.getSessionFactory(),
configuration.getDatabase().getValidationQuery()
);
// Register resources, filters and healthchecks
environment.jersey().register(new BlogResource(configuration.getSiteName(), articleDAO));
environment.jersey().register(new ArticleResource(articleDAO, userDAO));
environment.healthChecks().register("databaseHealthcheck", dbHealthCheck);
}}
註冊 Resources,
HealthChecks...
Application 類別 – run( )

39. 可使用 maven-shade 或 maven-assembly-plugin
包成 Fat JAR 檔案
命令列執行
java -jar [your_jar_file] server [your_yaml_file]
Ex. java –jar demo-0.0.1-SNAPSHOT.jar server demo.yaml
瀏覽器開啟 http://localhost:8080 即可開始使用應用程式
Build & Run

40. Demo
- A simple restful service -

41. Freemarker (http://freemarker.org)
Mustache (http://mustache.github.io)
另類作法：AssetsBundle + JavaScript MVC
View Layer

42. Demo
- A simple web application -

43. More
DropWizard?

44. Fallwizard (https://github.com/Berico-Technologies/Fallwizard)
dropwizard-springbundle:
(https://github.com/anthonych/Dropwizard-SpringBundle)
Dropwizard + Spring

45. https://github.com/rayokota/generator-angular-dropwizard
手工製作 AngularJS 程式 (使用 AssetsBundle)
使用 Yeoman + Angular-Dropwizard generator
或
Dropwizard + AngularJS

46. Yeoman + Angular-Dropwizard Generator
yo angular-dropwizard
命令列建立 Dropwizard 專案初步結構
yo angular-dropwizard:entity [your_entity_class_name]
Ex. yo angular-dropwizard:entity User
建立 Entity類別 (自動產生DAO、Resource 等類別)

47. grunt server
mvn exec:exec –pl [your_app-name]-service
Ex. mvn exec:exec –pl demo-service
mvn compile
編譯並執行 Service
執行 AngularJS 網頁應用程式

48. 最後...

49. Dropwizard 適合...

50. http://www.flickr.com/photos/psd/13109673843 by Paul Downey
大型應用也可以...

51. Dropwizard 不是...

52. Dropwizard 也許只是...

53. 一不小心...

54. 別忘了他還是...

55. 也許有一天...

56. Thank You!