关于Flume中Chanel.Selector.header解释
flume内置的ChannelSelector有两种，分别是Replicating和Multiplexing。
Replicating类型的ChannelSelector会针对每一个Event，拷贝到所有的Channel中，这是默认的ChannelSelector。
replicating类型的ChannelSelector例子如下
1 a1.sources = r1 2 a1.channels = c1 c2 # 如果有100个Event，那么c1和c2中都会有这100个事件 3 4 a1.channels.c1.type = memory 5 a1.channels.c1.capacity = 1000 6 a1.channels.c1.transactionCapacity = 100 7 8 9 a1.channels.c2.type = memory 10 a1.channels.c2.capacity = 1000 11 a1.channels.c2.transactionCapacity = 100
Multiplexing类型的ChannelSelector会根据Event中Header中的某个属性决定分发到哪个Channel。
multiplexing类型的ChannelSelector例子如下：
1 a1.sources = r1 2 3 a1.sources.source1.selector.type = multiplexing 4 a1.sources.source1.selector.header = validation # 以header中的validation对应的值作为条件 5 a1.sources.source1.selector.mapping.SUCCESS = c2 # 如果header中validation的值为SUCCESS，使用c2这个channel 6 a1.sources.source1.selector.mapping.FAIL = c1 # 如果header中validation的值为FAIL，使用c1这个channel 7 a1.sources.source1.selector.default = c1 # 默认使用c1这个channel
a1.sources.source1.selector.header = validation # 以header中的validation对应的值作为条件
同理，如下conf文件：
1 a1.sources = r1 2 a1.sinks = k1 k2 3 a1.channels = c1 c2 4 5 # Describe/configure the source 6 a1.sources.r1.type = exec 7 a1.sources.r1.command = tail -F /usr/lib/flume-ng/test.log 8 a1.sources.r1.interceptors = i1 9 a1.sources.r1.interceptors.i1.type = regex_extractor 10 a1.sources.r1.interceptors.i1.regex = (\\w+):(\\w+):(\\w+) 11 a1.sources.r1.interceptors.i1.serializers = s1 s2 s3 12 a1.sources.r1.interceptors.i1.serializers.s1.name = ip 13 a1.sources.r1.interceptors.i1.serializers.s2.name = domain 14 a1.sources.r1.interceptors.i1.serializers.s3.name = course 15 16 a1.sources.r1.selector.type = multiplexing 17 a1.sources.r1.selector.header = course 18 a1.sources.r1.selector.mapping.hadoop = c1 19 a1.sources.r1.selector.default = c2 20 21 22 # Describe the sink 23 a1.sinks.k1.type = file_roll 24 a1.sinks.k1.channel = c1 25 a1.sinks.k1.sink.directory = /tmp/multiplexing/flume_sink1 26 27 a1.sinks.k2.type = file_roll 28 a1.sinks.k2.channel = c2 29 a1.sinks.k2.sink.directory = /tmp/multiplexing/flume_sink2 30 31 # Use a channel which buffers events in memory 32 a1.channels.c1.type = memory 33 a1.channels.c1.capacity = 1000 34 a1.channels.c1.transactionCapacity = 100 35 36 a1.channels.c2.type = memory 37 a1.channels.c2.capacity = 1000 38 a1.channels.c2.transactionCapacity = 100 39 40 # Bind the source and sink to the channel 41 a1.sources.r1.channels = c1 c2 42 a1.sinks.k1.channel = c1 43 a1.sinks.k2.channel = c2
interceptor只对头部进行改变。
source r1中的头部有IP、Domain和cource三种信息，而r1的selector.header = course，表示selector只对IP，Domain和Cource中的Cource进行判断选择，然后再划分channel。
