Kotlin Implementation

DataCap supports custom plug-ins, and users can write their own plug-ins and integrate them into the system. This document mainly explains how to quickly integrate a plug-in into the DataCap system.

Note

This article demonstrates by integrating the StarRocks data storage system based on the JDBC protocol.

pom.xml Depend

<dependency>
    <groupId>io.edurt.datacap</groupId>
    <artifactId>datacap-spi</artifactId>
    <scope>provided</scope>
</dependency>
<dependency>
    <groupId>io.edurt.datacap</groupId>
    <artifactId>datacap-common</artifactId>
</dependency>
<dependency>
    <groupId>commons-beanutils</groupId>
    <artifactId>commons-beanutils</artifactId>
</dependency>
<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-api</artifactId>
</dependency>
<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-simple</artifactId>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>org.testcontainers</groupId>
    <artifactId>testcontainers</artifactId>
    <scope>test</scope>
</dependency>

The above configuration adds datacap-spi and datacap-common modules, and others are some auxiliary dependencies.

Warning

It should be noted that if you open the project separately, you need to specify the version number of each dependency.

Plugin Loader

class StarRocksPluginModule : AbstractPluginModule(), PluginModule {
    override fun getName(): String {
        return "StarRocks"
    }

    override fun getType(): PluginType {
        return PluginType.JDBC
    }

    override fun get(): AbstractPluginModule {
        return this
    }

    override fun configure() {
        val module = Multibinder.newSetBinder(binder(), String::class.java)
        module.addBinding().toInstance(this.javaClass.simpleName)
        val plugin: Multibinder<Plugin> = Multibinder.newSetBinder(binder(), Plugin::class.java)
        plugin.addBinding().to(StarRocksPlugin::class.java)
    }
}

The loader needs to inherit the AbstractPluginModule class and implement the PluginModule interface, so that the system will automatically load the plug-in into the system when it starts.

Note

It should be noted that you need to override the configure() method in the parent class and bind the plugin to the system.

Plugin Executor

class StarRocksPlugin : Plugin {
    private val log = getLogger(StarRocksPlugin::class.java)

    private var jdbcConfigure: JdbcConfigure? = null
    private var jdbcConnection: JdbcConnection? = null
    private var jdbcResponse: Response? = null

    override fun name(): String {
        return "StarRocks"
    }

    override fun description(): String {
        return "Integrate StarRocks data sources"
    }

    override fun type(): PluginType {
        return PluginType.JDBC
    }

    override fun connect(configure: Configure?) {
        try {
            log.info("Connecting to StarRocks")
            jdbcResponse = Response()
            jdbcConfigure = JdbcConfigure()
            BeanUtils.copyProperties(jdbcConfigure, configure)
            jdbcConfigure!!.jdbcDriver = "com.mysql.cj.jdbc.Driver"
            jdbcConfigure!!.jdbcType = "mysql"
            jdbcConnection = object : JdbcConnection(jdbcConfigure, jdbcResponse) {}
        } catch (ex: Exception) {
            jdbcResponse!!.isConnected = false
            jdbcResponse!!.message = ex.message
        }
    }

    override fun execute(content: String?): Response {
        if (ObjectUtils.isNotEmpty(jdbcConnection)) {
            log.info("Execute starrocks plugin logic started")
            jdbcResponse = jdbcConnection?.response
            val processor = JdbcAdapter(jdbcConnection)
            jdbcResponse = processor.handlerExecute(content)
            log.info("Execute starrocks plugin logic end")
        }
        destroy()
        return jdbcResponse!!
    }

    override fun destroy() {
        if (ObjectUtils.isNotEmpty(jdbcConnection)) {
            jdbcConnection?.destroy()
            jdbcConnection = null
        }
    }
}

The executor needs to implement the Plugin interface, which provides the following methods

• name(): Plugins have unique names, and plugins with the same name will only take effect the first time they are loaded
• description(): A description of the plugin
• type(): Plugin type
• connect(Configure configure): Plug-ins need connection information in advance, such as the current plug-in plug-in, which is the connection phase of the plug-in (the system presets the HTTP connection method to be used directly).
• execute(String content): Execute the operation logic
• destroy(): The final destruction of the plug-in, note that the destruction needs to contain the information in the connection

Plugin Converter

The plug-in converter is used to convert the result after the current plug-in is executed, and convert it into logic that can be used in DataCap. It is mainly used to encapsulate Response to return the result.

This article is a JDBC-based plug-in, so some functions can be realized by directly inheriting the JdbcAdapter parent class.

SPI loader

Add META-INF and services directory under resources source directory

Warning

services needs to be in the resources directory

Create the io.edurt.datacap.spi.PluginModule file, as follows

io.edurt.datacap.plugin.jdbc.starrocks.StarRocksPluginModule

The content of this file is the plugin loading module we defined.

Warning

The unit test of the plug-in can refer to the published plug-in for testing

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Last update: December 7, 2023
Created: April 21, 2023

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