数据迁移工具 - Flyway

对于数据迁移的概念，相信大家已经都比较熟悉。那么，什么是数据迁移？为什么需要数据迁移？在这里就不再做相关分享啦~。接下来主要分享一下数据迁移工具 Flyway 使用。

Flyway is the Apache v2 licensed open-source tool that makes database migrations easy. It strongly favors simplicity and convention over configuration.

Flyway 是一款开源的数据库迁移工具，它认为简单和约定优于配置。没有繁琐的配置，有 6 个主要基本命令：Migrate, Clean, Info, Validate, Baseline 和 Repair。

Flyway received the highest distinction on the Thoughtworks Technology Radar by being placed in the adopt category.

如何使用 Flyway？

Flyway支持很多种和应用集成的方法，这里主要分享一下Gradle集成Flyway的使用。

Setup Repo db-migration-flyway：

$ gradle init --type java-libray

Add Gradle Flyway plugin

• Change build.gradle file content

  buildscript {
      repositories {
          maven { url "https://plugins.gradle.org/m2/" }
      }
      dependencies {
          classpath "gradle.plugin.com.boxfuse.client:flyway-release:4.1.1"
      }
  }
  
  apply plugin: "idea"
  apply plugin: 'java'
  apply plugin: "org.flywaydb.flyway"

• Build repo

  $ ./gradlew build

Config Flyway

• Change [build.gradle] file content

  buildscript {
      repositories {
          maven { url "https://plugins.gradle.org/m2/" }
      }
      dependencies {
          classpath "gradle.plugin.com.boxfuse.client:flyway-release:4.1.1"
      }
  }
  
  apply plugin: "idea"
  apply plugin: 'java'
  apply plugin: "org.flywaydb.flyway"
  
  flyway {
      driver = 'com.mysql.jdbc.Driver'
      url = "jdbc:mysql://127.0.0.1:3306/flyway_dev"
      user = 'mysql'
      password = 'mysql'
      table = 'flyway_dev_schema_version'
      locations = ["filesystem:${projectDir}/src/main/resources/db/migration/mysql"]
      sqlMigrationPrefix = 'MySQL-'
  }
  
  repositories {
      jcenter()
  }
  
  dependencies {
      compile 'mysql:mysql-connector-java:5.1.34'
  }

• Build repo

  $ ./gradlew build

Add Migration Scripts

• Create file MySQL-1_1__create_users_table.sql

  CREATE TABLE USERS (
    ID         BIGINT PRIMARY KEY    AUTO_INCREMENT,
    USERNAME   VARCHAR(32)  NOT NULL UNIQUE,
    CREATED_AT TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3)
  );

• Create Mysql Database flyway_dev with user mysql and password mysql

• Migration

  $ ./gradlew flywayMigrate -i

  

配置管理

对于DEV、QA、TEST、STAGE、PROD针对不同的环境，需要会使用不一样的数据库配置。

• 在工程目录下创建文件config/dev/db.properties, config/test/db.properties, config/prod/db.properties:

  // config/dev/db.properties
  db.url=jdbc:mysql://127.0.0.1:3306/flyway_dev
  db.user=mysql
  db.password=mysql
  
  // config/test/db.properties
  db.url=jdbc:mysql://127.0.0.1:3306/flyway_test
  db.user=mysql
  db.password=mysql
  
  // config/prod/db.properties
  db.url=jdbc:mysql://127.0.0.1:3306/flyway_prod
  db.user=mysql
  db.password=mysql

• 修改 build.gradle 文件

  buildscript {
      repositories {
          maven { url "https://plugins.gradle.org/m2/" }
      }
      dependencies {
          classpath "gradle.plugin.com.boxfuse.client:flyway-release:4.1.1"
      }
  }
  
  apply plugin: "idea"
  apply plugin: 'java'
  apply plugin: "org.flywaydb.flyway"
  
  def properties = new Properties()
  properties.load(project.file("config/${env}/db.properties").newReader())
  
  flyway {
      driver = 'com.mysql.jdbc.Driver'
      url = properties.get('db.url')
      user = properties.get('db.user')
      password = properties.get('db.password')
      table = 'flyway_dev_schema_version'
      locations = ["filesystem:${projectDir}/src/main/resources/db/migration/mysql"]
      sqlMigrationPrefix = 'MySQL-'
  }
  
  repositories {
      jcenter()
  }
  
  dependencies {
      compile 'mysql:mysql-connector-java:5.1.34'
  }

• Create Mysql Database flyway_test with user mysql and password mysql

• Migration test env

  $ ./gradlew -Penv=test flywayMigrate -i

写在最后

这里只是简单的分享了一下，Gradle 和 Flyway 的集成。Flyway 还有很多功能值得去探索…

参考

---

Flyway