使用Flume-Taildir和rocketmq-flume与RocketMQ的结合

一、Fume-Taidir

Flume1.7.0加入了taildirSource作为agent的source。可以说是 Spooling Directory Source + Exec Source 的结合体。可以监控多个目录，并且使用正则表达式匹配该目录中的文件名进行实时收集，并记录每个文件最新消费位置，Agent进程重启后不会有重复消费的问题。

官方文档：https://flume.apache.org/FlumeUserGuide.html#taildir-source

Exec source：适用于监控一个实时追加的文件，但不能保证数据不丢失

Spooldir Source：能够保证数据不丢失，且能够实现断点续传，但延迟较高，不能实时监控

Taildir Source：既能够实现断点续传，又可以保证数据不丢失，还能够进行实时监控

Taildir Source 维护了一个 Json 格式的 positionFile，其会定期的往 positionFile 中更新每个文件读取到的最新的位置，因此能够实现断点续传。

[
  {"inode":1717446,"pos":8,"file":"/tmp/upload/456.txt"},
  {"inode":1717449,"pos":8,"file":"/tmp/upload/789.txt"},
  {"inode":1717442,"pos":12,"file":"/tmp/upload/123.txt"}
]

配置文件示例：

agent1.sources = source1  
agent1.channels = channel1  
agent1.sinks = avroSink  
  
# describe/configure source1  
agent1.sources.source1.type = TAILDIR
agent1.sources.source1.channels = channel1
agent1.sources.source1.channels.skipToEnd = True

# throught JSON format to record the inode, the absolute path and the last position of each tailing file.For to continual work
agent1.sources.source1.positionFile = ./taildir_position.json

# throught Space-separated list file dir which will been tail
agent1.sources.source1.filegroups = f1 f2
# define f1 info.
agent1.sources.source1.filegroups.f1 = /usr/local/tomcat/logs/ac/ac.log.*
agent1.sources.source1.headers.f1.headerKey1 = value1
agent1.sources.source1.filegroups.f2 = /usr/local/tomcat/logs/gi/gi.log.*
agent1.sources.source1.headers.f2.headerKey1 = value2
agent1.sources.source1.headers.f2.headerKey2 = value2-2
agent1.sources.source1.fileHeader = true
  
# use a channel which buffers events in memory  
# type:memory or file is to temporary to save buffer data which is sink using  
agent1.channels.channel1.type=memory  
agent1.channels.channel1.capacity = 1000
agent1.channels.channel1.transactionCapacity = 1000

agent1.sinks.avroSink.type = avro
agent1.sinks.avroSink.channel = channel1
agent1.sinks.avroSink.hostname = 192.168.216.201
agent1.sinks.avroSink.port =  4545
agent1.sinks.avroSink.batch-size = 5

二、 Flume-ng与RocketMQ之间的消息接收和投递

Rocket-Flume：https://github.com/apache/rocketmq-externals/tree/master/rocketmq-flume 

agent1.sources = source1
agent1.channels = channel1
agent1.sinks = sink1

agent1.sources.source1.type = TAILDIR
agent1.sources.source1.positionFile = /usr/local/apache-flume-1.9.0-bin/db/taildir_position.json
agent1.sources.source1.filegroups = seqGenSrc
agent1.sources.source1.filegroups.seqGenSrc = /tmp/oss-yiruike-logs/raw/chaopai_push/.*txt
agent1.sources.source1.fileHeader = false
agent1.sources.source1.batchSize = 1

agent1.channels.channel1.type = memory
agent1.channels.channel1.capacity = 100
agent1.channels.channel1.transactionCapacity = 100
agent1.channels.channel1.keep-alive = 3

agent1.sinks.sink1.type = org.apache.rocketmq.flume.ng.sink.RocketMQSink
agent1.sinks.sink1.nameserver = 172.17.213.74:9876;172.17.213.75:9876;172.17.213.75:9876
agent1.sinks.sink1.producerGroup = MyProducerGroup_1
agent1.sinks.sink1.topic = ts-push-delineation

agent1.sources.source1.channels = channel1
agent1.sinks.sink1.channel = channel1

启动Flume

# cd /usr/local/apache-flume-1.9.0-bin ; nohup bin/flume-ng agent -c conf -f conf/flume.conf -n agent1 >/dev/null 2>&1 &