Source是负责接收数据到Flume Agent的组件。Source组件可以处理各种类型、各种格式的日志数据，包括avro、thrift、exec、jms、spooling directory、netcat、sequence generator、syslog、http、legacy。官方提供的source类型已经很多，但是有时候并不能满足实际开发当中的需求，此时我们就需要根据实际需求自定义某些source。
搭建maven项目

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>

	<groupId>com.yy.brick</groupId>
	<artifactId>flume-log-extrator</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>yy-brick-flume</name>
	<url>http://maven.apache.org</url>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
	</properties>

	<dependencies>
		<dependency>
			<groupId>com.alibaba</groupId>
			<artifactId>fastjson</artifactId>
			<version>1.2.40</version>
		</dependency>
		<dependency>
			<groupId>org.apache.commons</groupId>
			<artifactId>commons-collections4</artifactId>
			<version>4.1</version>
		</dependency>
		<dependency>
			<groupId>org.apache.commons</groupId>
			<artifactId>commons-lang3</artifactId>
			<version>3.6</version>
		</dependency>
		<dependency>
			<groupId>org.apache.flume</groupId>
			<artifactId>flume-ng-core</artifactId>
			<version>1.7.0</version>
		</dependency>

	</dependencies>
	<build>
		<!-- <resources> <resource> <directory>src/main/java</directory> <filtering>true</filtering> <includes> <include>**/*.properties</include> <include>**/*.xml</include> 
			<include>**/*.dat</include> </includes> </resource> </resources> -->
		<plugins>
			<plugin>
				<groupId>org.codehaus.mojo</groupId>
				<artifactId>build-helper-maven-plugin</artifactId>
				<version>1.7</version>

				<executions>
					<execution>
						<id>add-resource</id>
						<phase>generate-resources</phase>
						<goals>
							<goal>add-resource</goal>
						</goals>
						<configuration>
							<resources>
								<resource>
									<directory>src/main/resources</directory>
								</resource>
							</resources>
						</configuration>
					</execution>
				</executions>
			</plugin>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-surefire-plugin</artifactId>
				<version>2.17</version>
				<configuration>
					<skipTests>true</skipTests>
				</configuration>
			</plugin>
		</plugins>
	</build>

</project>

官网代码块 Flume 1.9.0 Developer Guide — Apache Flume

public class MySource extends AbstractSource implements Configurable, PollableSource {
  private String myProp;

  @Override
  public void configure(Context context) {
    String myProp = context.getString("myProp", "defaultValue");

    // Process the myProp value (e.g. validation, convert to another type, ...)

    // Store myProp for later retrieval by process() method
    this.myProp = myProp;
  }

  @Override
  public void start() {
    // Initialize the connection to the external client
  }

  @Override
  public void stop () {
    // Disconnect from external client and do any additional cleanup
    // (e.g. releasing resources or nulling-out field values) ..
  }

  @Override
  public Status process() throws EventDeliveryException {
    Status status = null;

    try {
      // This try clause includes whatever Channel/Event operations you want to do

      // Receive new data
      Event e = getSomeData();

      // Store the Event into this Source's associated Channel(s)
      getChannelProcessor().processEvent(e);

      status = Status.READY;
    } catch (Throwable t) {
      // Log exception, handle individual exceptions as needed

      status = Status.BACKOFF;

      // re-throw all Errors
      if (t instanceof Error) {
        throw (Error)t;
      }
    } finally {
      txn.close();
    }
    return status;
  }
}