从启动到关闭 | SeaTunnel2.1.1源码解析

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GitHub:https://github.com/apache/incubator-seatunnel

从启动到关闭 | SeaTunnel2.1.1源码解析_第1张图片

目录

本文转载自Adobee Chen的博客-CSDN博客,看看是否有你感兴趣的吧!

如有出错,请多指正。

一、启动脚本解析

二、源码解析

01 入口

02 execute()核心方法

  1. 其中 BaseSource、BaseTransform、BaseSink都是接口、都实现Plugin接口。他们的实现类就是对应的插件类型
  2. execute()方法向下走,创建一个执行环境。
  3. 调用plugin.prepare(env)
  4. 最后启动 execution.start(sources, transforms, sinks);执行flink 代码程序
  5. 最后关闭

一、启动脚本解析

在 /bin/start-seatunnel-flink.sh

#!/bin/bash
​
function usage() {
  echo "Usage: start-seatunnel-flink.sh [options]"
  echo "  options:"
  echo "    --config, -c FILE_PATH        Config file"
  echo "    --variable, -i PROP=VALUE     Variable substitution, such as -i city=beijing, or -i date=20190318"
  echo "    --check, -t                   Check config"
  echo "    --help, -h                    Show this help message"
}
 
if [[ "$@" = *--help ]] || [[ "$@" = *-h ]] || [[ $# -le 1 ]]; then
  usage
  exit 0
fi
 
is_exist() {
    if [ -z $1 ]; then
      usage
      exit -1
    fi
}
 
PARAMS=""
while (( "$#" )); do
  case "$1" in
    -c|--config)
      CONFIG_FILE=$2
      is_exist ${CONFIG_FILE}
      shift 2
      ;;
 
    -i|--variable)
      variable=$2
      is_exist ${variable}
      java_property_value="-D${variable}"
      variables_substitution="${java_property_value} ${variables_substitution}"
      shift 2
      ;;
 
    *) # preserve positional arguments
      PARAMS="$PARAMS $1"
      shift
      ;;
 
  esac
done
 
if [ -z ${CONFIG_FILE} ]; then
  echo "Error: The following option is required: [-c | --config]"
  usage
  exit -1
fi
 
# set positional arguments in their proper place
eval set -- "$PARAMS"
 
BIN_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
APP_DIR=$(dirname ${BIN_DIR})
CONF_DIR=${APP_DIR}/config
PLUGINS_DIR=${APP_DIR}/lib
DEFAULT_CONFIG=${CONF_DIR}/application.conf
CONFIG_FILE=${CONFIG_FILE:-$DEFAULT_CONFIG}
 
assemblyJarName=$(find ${PLUGINS_DIR} -name seatunnel-core-flink*.jar)
 
if [ -f "${CONF_DIR}/seatunnel-env.sh" ]; then
    source ${CONF_DIR}/seatunnel-env.sh
fi
 
string_trim() {
    echo $1 | awk '{$1=$1;print}'
}
 
export JVM_ARGS=$(string_trim "${variables_substitution}")
 
 
exec ${FLINK_HOME}/bin/flink run \
    ${PARAMS} \
    -c org.apache.seatunnel.SeatunnelFlink \
    ${assemblyJarName} --config ${CONFIG_FILE}

其中: 启动脚本能接收的 --config --variable --check(还不支持) --help

只要不是 config、variable参数就放到PARAMS参数里,最后执行flink 执行命令,PARAMS当作flink参数执行。

org.apache.seatunnel.SeatunnelFlink 这个类就是主入口

二、源码解析

01 入口

public class SeatunnelFlink {
 
    public static void main(String[] args) throws Exception {
        FlinkCommandArgs flinkArgs = CommandLineUtils.parseFlinkArgs(args);
        Seatunnel.run(flinkArgs);
    }
 
}

FlinkCommandArgs中进行命令行参数解析

  public static FlinkCommandArgs parseFlinkArgs(String[] args) {
        FlinkCommandArgs flinkCommandArgs = new FlinkCommandArgs();
        JCommander.newBuilder()
            .addObject(flinkCommandArgs)
            .build()
            .parse(args);
        return flinkCommandArgs;
    }

进入到Seatunnel.run(flinkArgs);

  public static FlinkCommandArgs parseFlinkArgs(String[] args) {
        FlinkCommandArgs flinkCommandArgs = new FlinkCommandArgs();
        JCommander.newBuilder()
            .addObject(flinkCommandArgs)
            .build()
            .parse(args);
        return flinkCommandArgs;
    }

进入到CommandFactory.createCommand(commandArgs)

根据不同的类型选择Command

我们看的是flinkCommand

    public static extends CommandArgs> Command createCommand(T commandArgs) {
        switch (commandArgs.getEngineType()) {
            case FLINK:
                return (Command) new FlinkCommandBuilder().buildCommand((FlinkCommandArgs) commandArgs);
            case SPARK:
                return (Command) new SparkCommandBuilder().buildCommand((SparkCommandArgs) commandArgs);
            default:
                throw new RuntimeException(String.format("engine type: %s is not supported", commandArgs.getEngineType()));
        }
    }

进入到 buildCommand

根据是否检查config进入到不同的实现类

    public Command buildCommand(FlinkCommandArgs commandArgs) {
        return commandArgs.isCheckConfig() ? new FlinkConfValidateCommand() : new FlinkTaskExecuteCommand();
    }

FlinkConfValidateCommand、

FlinkTaskExecuteCommand

两个类都实现了Command类

并且都只有一个execute()方法

public class FlinkConfValidateCommand implements Command
public class FlinkTaskExecuteCommand extends BaseTaskExecuteCommand

**在SeaTunnel.run(flinkArgs)**进入

command.execute(commandArgs);

我们先看FlinkTaskExecuteCommand

类中的execute方法

02 execute()核心方法

public void execute(FlinkCommandArgs flinkCommandArgs) {
        //flink
        EngineType engine = flinkCommandArgs.getEngineType();
        // --config
        String configFile = flinkCommandArgs.getConfigFile();
        //将String变成Config类
        Config config = new ConfigBuilder<>(configFile, engine).getConfig();
        //解析执行上下文
        ExecutionContext executionContext = new ExecutionContext<>(config, engine);
        //解析 sources模块
        List sources = executionContext.getSources(); transforms = executionContext.getTransforms(); sinks = executionContext.getSinks(); execution = new ExecutionFactory<>(executionContext).createExecution()) {
            //准备
            prepare(executionContext.getEnvironment(), sources, transforms, sinks);
            //启动
            execution.start(sources, transforms, sinks);
            //关闭
            close(sources, transforms, sinks);
        } catch (Exception e) {
            throw new RuntimeException("Execute Flink task error", e);
        }
    }

1.其中 BaseSource、BaseTransform、BaseSink都是接口、都实现Plugin接口。他们的实现类就是对应的插件类型

从启动到关闭 | SeaTunnel2.1.1源码解析_第2张图片

从启动到关闭 | SeaTunnel2.1.1源码解析_第3张图片

如果我们的source、sink是kafka的话那么对应的就是source就是KafkaTableStream、Sink就是KafkaSink

2. execute()方法向下走,创建一个执行环境。

从启动到关闭 | SeaTunnel2.1.1源码解析_第4张图片

进入ExecutionFactory种的createExecution()

    public Execution createExecution() {) execution;

进入到FlinkStreamExecution中,可以看到最终是创建flink 执行环境。

 private final FlinkEnvironment flinkEnvironment;
 
    public FlinkStreamExecution(FlinkEnvironment streamEnvironment) {
        this.flinkEnvironment = streamEnvironment;
    }

3. 调用plugin.prepare(env)

    protected final void prepare(E env, List extends Plugin>... plugins) {
        for (List extends Plugin> pluginList : plugins) {
            pluginList.forEach(plugin -> plugin.prepare(env));
        }
    }

例如kafka->kafka

KafkaTableStream prepare

    public void prepare(FlinkEnvironment env) {
        topic = config.getString(TOPICS);
        PropertiesUtil.setProperties(config, kafkaParams, consumerPrefix, false);
        tableName = config.getString(RESULT_TABLE_NAME);
        if (config.hasPath(ROWTIME_FIELD)) {
            rowTimeField = config.getString(ROWTIME_FIELD);
            if (config.hasPath(WATERMARK_VAL)) {
                watermark = config.getLong(WATERMARK_VAL);
            }
        }
        String schemaContent = config.getString(SCHEMA);
        format = FormatType.from(config.getString(SOURCE_FORMAT).trim().toLowerCase());
        schemaInfo = JSONObject.parse(schemaContent, Feature.OrderedField);
    }

KafkaSink prepare

   public void prepare(FlinkEnvironment env) {
        topic = config.getString("topics");
        if (config.hasPath("semantic")) {
            semantic = config.getString("semantic");
        }
        String producerPrefix = "producer.";
        PropertiesUtil.setProperties(config, kafkaParams, producerPrefix, false);
        kafkaParams.put("key.serializer", "org.apache.kafka.common.serialization.ByteArraySerializer");
        kafkaParams.put("value.serializer", "org.apache.kafka.common.serialization.ByteArraySerializer");
    }

4.启动execution.start

(sources, transforms, sinks);

通过步骤2.已经知道execution是根据不同引擎创建不同的执行环境,kafka是FlinkStreamExecution。那么就在FlinkStreamExecution中找到start()方法

5.执行flink 代码程序

其中sorce.getDate在KafkaTableStream中的getDate方法,sink在KafkaSink中的outputStream方法

 public void start(List sources, List transforms, List sinks) throws Exception {
        List data = new ArrayList<>();

6.最后关闭

    protected final void close(List extends Plugin>... plugins) {
        PluginClosedException exceptionHolder = null;
        for (List extends Plugin> pluginList : plugins) {
            for (Plugin plugin : pluginList) {
                try (Plugin> closed = plugin) {
                    // ignore
                } catch (Exception e) {
                    exceptionHolder = exceptionHolder == null ?
                            new PluginClosedException("below plugins closed error:") : exceptionHolder;
                    exceptionHolder.addSuppressed(new PluginClosedException(
                            String.format("plugin %s closed error", plugin.getClass()), e));
                }
            }
        }
        if (exceptionHolder != null) {
            throw exceptionHolder;
        }
    }

Apache SeaTunnel

来,和社区一同成长!

Apache SeaTunnel(Incubating) 是一个分布式、高性能、易扩展、用于海量数据(离线&实时)同步和转化的数据集成平台。

仓库地址: https://github.com/apache/incubator-seatunnel

网址:https://seatunnel.apache.org/

**Proposal:**https://cwiki.apache.org/confluence/display/INCUBATOR/SeaTunnelProposal

**Apache SeaTunnel(Incubating) 2.1.0 下载地址:**https://seatunnel.apache.org/download

衷心欢迎更多人加入!

我们相信,在**「Community Over Code」(社区大于代码)、「Open and Cooperation」(开放协作)、「Meritocracy」**(精英管理)、以及「**多样性与共识决策」**等 The Apache Way 的指引下,我们将迎来更加多元化和包容的社区生态,共建开源精神带来的技术进步!

我们诚邀各位有志于让本土开源立足全球的伙伴加入 SeaTunnel 贡献者大家庭,一起共建开源!

提交问题和建议:https://github.com/apache/incubator-seatunnel/issues

贡献代码:https://github.com/apache/incubator-seatunnel/pulls

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加入 Slack:https://join.slack.com/t/apacheseatunnel/shared_invite/zt-1cmonqu2q-ljomD6bY1PQ~oOzfbxxXWQ

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