Microserviços em Kotlin com Dropwizard

Apresentação para o Kotlin Meetup São Paulo em 25 de Julho de 2020

Transcript

1. Microserviços em Kotlin com
   Dropwizard
   Felipe Lima
   Kotlin Meetup São Paulo
   25 de Junho de 2020
   felipecsl.com
   @felipecsl
   

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2. Introdução
   

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3. Um pouco de história…
   

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6. Dropwizard
   

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7. Dropwizard @ Airbnb
   

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8. Fonte: website oficial - dropwizard.io
   “Dropwizard is a Java framework for
   developing ops-friendly, high-
   performance, RESTful web services.”
   

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9. “Elefante na sala"
   

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10. “Tá, mas por que diabos eu
    deveria usar Dropwizard ao invés
    de ”
    

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11. Fonte: https://blog.overops.com/java-bootstrap-dropwizard-vs-spring-boot
    Dropwizard vs. Spring Boot
    

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13. Meu favorito
    

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14. • Criado em 2011 no Yammer
    
    • Arquitetura modular
    
    • Foco em produtividade, “get things done”
    
    • Java centric
    
    • Utiliza Jersey e Jetty
    Características
    

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15. Modularidade
    https://modules.dropwizard.io/official/
    

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16. Simplicidade
    companion object {
    @Throws(Exception::class)
    @JvmStatic
    fun main(args: Array) {
    BrokerApplication().run(*args)
    }
    }
    

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17. Simplicidade
    class BrokerApplication : Application() {
    override fun initialize(bootstrap: Bootstrap) {
    bootstrap.apply {
    addBundle(webSocketBundle)
    addBundle(SslReloadBundle())
    addBundle(RedirectBundle(HttpsRedirect()))
    }
    }
    override fun run(configuration: BrokerConfiguration, environment: Environment) {
    userDao = DaoFactory(environment, configuration).newDao(UserDao::class.java)
    sessionManager = SessionManagerFactory.newInstance(
    userDao, objectMapper, configuration
    )
    environment.jersey().register(StatusResource(sessionManager))
    environment.healthChecks().register("template", BrokerHealthCheck())
    environment.jersey().register(UsersResource(userDao, sessionManager))
    }
    

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19. REST
    "Eclipse Jersey is a REST framework
    that provides a JAX-RS (JSR-370)
    implementation”
    https://eclipse-ee4j.github.io/jersey/
    

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20. REST
    https://github.com/jax-rs/spec/blob/master/spec.pdf
    

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21. REST
    @Path("/status")
    @Produces(MediaType.APPLICATION_JSON)
    class StatusResource(private val sessionManager: SessionManager) {
    @GET
    @Timed
    fun healthStatus(): HealthStatus {
    return HealthStatus(sessionManager.totalActiveSessions())
    }
    }
    

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22. REST
    @Path("/users")
    @Produces(MediaType.APPLICATION_JSON)
    class UsersResource(
    private val userDao: UserDao,
    private val sessionManager: SessionManager
    ) {
    @POST
    @Timed
    @Consumes(MediaType.APPLICATION_JSON)
    fun create(user: User): Response {
    userDao.insert(user)
    return Response.ok().build()
    }
    @PUT
    @Timed
    @Consumes(MediaType.APPLICATION_JSON)
    fun update(user: User): Response {
    userDao.updateUserIdByFcmToken(user)
    return Response.ok().build()
    }
    }
    

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23. Configurações
    • Único arquivo YAML
    
    • Passado por parâmetro para o server via linha de comando
    
    • Pode ser utilizado para centralizar todas as configurações do servidor
    

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24. Configurações
    // build.gradle
    run {
    args 'server', 'src/dist/config/broker.dev.yml'
    }
    

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25. Configurações
    database:
    driverClass: org.postgresql.Driver
    user: felipecsl
    password:
    url: jdbc:postgresql://localhost/clairvoyance_dev
    properties:
    charSet: UTF-8
    # the maximum amount of time to wait on an empty pool before throwing an exception
    maxWaitForConnection: 1s
    # the SQL query to run when validating a connection's liveness
    validationQuery: "/* MyService Health Check */ SELECT 1"
    # the minimum number of connections to keep open
    minSize: 8
    logValidationErrors: true
    # the maximum number of connections to keep open
    maxSize: 32
    # whether or not idle connections should be validated
    checkConnectionWhileIdle: false
    # the amount of time to sleep between runs of the idle connection validation, abandoned cleaner and idle pool resizing
    evictionInterval: 10s
    # the minimum amount of time an connection must sit idle in the pool before it is eligible for eviction
    minIdleTime: 1 minute
    server:
    applicationContextPath: /
    applicationConnectors:
    - type: http
    port: 8080
    

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26. Configurações
    class BrokerApplication : Application() {
    // ...
    }
    

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27. Configurações
    class BrokerConfiguration : Configuration() {
    @JsonProperty
    var fcmCredentialJsonPath: String? = null
    @JsonProperty
    var iceConfigFilePath: String? = null
    @JsonProperty
    var database: DataSourceFactory = DataSourceFactory()
    }
    

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28. Database
    implementation "io.dropwizard:dropwizard-jdbi3:$dropwizardVersion"
    

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29. Database
    @RegisterRowMapper(UserMapper::class)
    interface UserDao {
    @SqlQuery("SELECT * FROM users") fun all(): List
    @SqlQuery("SELECT * FROM users WHERE user_id = :user_id")
    fun findByUserId(@Bind("user_id") userId: String): User?
    @SqlUpdate("UPDATE users SET user_id = :user_id,
    fcm_token = :fcm_token WHERE ID = :id")
    fun updateById(@BindBean user: User): Int
    @SqlUpdate("INSERT INTO users (user_id, fcm_token)
    VALUES (:user_id, :fcm_token)")
    fun insert(@BindBean user: User): Int
    @SqlUpdate("DELETE FROM users") fun deleteAll(): Int
    }
    

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30. Database Migrations
    // build.gradle
    plugins {
    id "org.flywaydb.flyway" version "6.4.0"
    }
    flyway {
    url = 'jdbc:h2:file:./clairvoyance_test'
    user = ‘fulano_de_tal’
    }
    

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31. Database Migrations
    private fun initFlyway(configuration: BrokerConfiguration) {
    val database = configuration.database
    Flyway.configure()
    .dataSource(database.url, database.user, database.password)
    .load()
    .migrate()
    }
    

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32. Database Migrations
    

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33. Frontend
    • Freemarker
    
    • Mustache
    
    

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34. Testing
    testImplementation "io.dropwizard:dropwizard-testing:$dropwizardVersion"
    

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35. Testing @ExtendWith(DropwizardExtensionsSupport::class)
    class BrokerApplicationTest {
    private val client = OkHttpClient.Builder().build()
    private val localPort = DROPWIZARD.localPort
    @Test fun status() {
    val client = JerseyClientBuilder().build()
    val result = client
    .target(“http://localhost:$localPort/status")
    .request()
    .get(String::class.java)
    assertThat(result).isEqualTo("""{"activeSessions":0}""")
    }
    companion object {
    private val DROPWIZARD = DropwizardAppExtension(
    BrokerApplication::class.java,
    ResourceHelpers.resourceFilePath("broker.yml")
    )
    }
    }
    

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36. Perguntas?
    

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37. Obrigado!
    

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