Flume代理：将主机添加到消息，然后发布到kafka主题

Question

我们开始通过将消息发布到Kafka主题来整合来自应用程序的事件日志数据。 虽然我们可以直接从应用程序写入Kafka，但我们选择将其视为一般问题并使用Flume代理。 这提供了一些灵活性：如果我们想从服务器捕获其他东西，我们可以只是拖尾不同的源并发布到不同的Kafka主题。

我们创建了一个Flume代理程序配置文件来拖尾日志并发布到Kafka主题：

tier1.sources  = source1
tier1.channels = channel1
tier1.sinks = sink1

tier1.sources.source1.type = exec
tier1.sources.source1.command = tail -F /var/log/some_log.log
tier1.sources.source1.channels = channel1

tier1.channels.channel1.type = memory
tier1.channels.channel1.capacity = 10000
tier1.channels.channel1.transactionCapacity = 1000

tier1.sinks.sink1.type = org.apache.flume.sink.kafka.KafkaSink
tier1.sinks.sink1.topic = some_log
tier1.sinks.sink1.brokerList = hadoop01:9092,hadoop02.com:9092,hadoop03.com:9092
tier1.sinks.sink1.channel = channel1
tier1.sinks.sink1.batchSize = 20

不幸的是，消息本身并没有指定生成它们的主机。 如果我们在多个主机上运行应用程序并且发生错误，我们无法确定哪个主机生成了该消息。

我注意到，如果Flume直接写入HDFS，我们可以使用Flume拦截器写入特定的HDFS位置。 虽然我们可能会对Kafka做类似的事情，即为每个服务器创建一个新主题，但这可能会变得难以处理。 我们最终会有数千个主题。

当Flume发布到Kafka主题时，它能否附加/包含原始主机的主机名？

Answer 1

您可以创建一个自定义TCP源，它读取客户端地址并将其添加到标头中。

@Override
    public void configure(Context context) {
        port = context.getInteger("port");
        buffer = context.getInteger("buffer");

        try{
            serverSocket = new ServerSocket(port);
            logger.info("FlumeTCP source initialized");
        }catch(Exception e) {
            logger.error("FlumeTCP source failed to initialize");
        }
    }

@Override
    public void start() {
        try {
            clientSocket = serverSocket.accept();
            receiveBuffer = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
            logger.info("Connection established with client : " + clientSocket.getRemoteSocketAddress());
            final ChannelProcessor channel = getChannelProcessor();
            final Map<String, String> headers = new HashMap<String, String>();
            headers.put("hostname", clientSocket.getRemoteSocketAddress().toString());
            String line = "";
            List<Event> events = new ArrayList<Event>();

            while ((line = receiveBuffer.readLine()) != null) {
                Event event = EventBuilder.withBody(
                        line, Charset.defaultCharset(),headers);

                logger.info("Event created");
                events.add(event);
                if (events.size() == buffer) {
                    channel.processEventBatch(events);
                }
            }
        } catch (Exception e) {

        }
        super.start();
    }

flume-conf.properties可以配置为：

# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#  http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.


# The configuration file needs to define the sources, 
# the channels and the sinks.
# Sources, channels and sinks are defined per agent, 
# in this case called 'agent'

agent.sources = CustomTcpSource
agent.channels = memoryChannel
agent.sinks = loggerSink

# For each one of the sources, the type is defined
agent.sources.CustomTcpSource.type = com.vishnu.flume.source.CustomFlumeTCPSource
agent.sources.CustomTcpSource.port = 4443
agent.sources.CustomTcpSource.buffer = 1


# The channel can be defined as follows.
agent.sources.CustomTcpSource.channels = memoryChannel

# Each sink's type must be defined
agent.sinks.loggerSink.type = logger

#Specify the channel the sink should use
agent.sinks.loggerSink.channel = memoryChannel

# Each channel's type is defined.
agent.channels.memoryChannel.type = memory

# Other config values specific to each type of channel(sink or source)
# can be defined as well
# In this case, it specifies the capacity of the memory channel
agent.channels.memoryChannel.capacity = 100

我发送了一条测试消息来测试它，它看起来像：

Event: { headers:{hostname=/127.0.0.1:50999} body: 74 65 73 74 20 6D 65 73 73 61 67 65             test message }

我已经在我的github上传了这个项目

Answer 2

如果您正在使用exec源，则不会阻止您运行智能命令以将主机名添加到日志文件内容前面。

注意：如果命令使用管道之类的东西，你还需要像这样指定shell：

tier1.sources.source1.type = exec
tier1.sources.source1.shell = /bin/sh -c
tier1.sources.source1.command =  tail -F /var/log/auth.log | sed --unbuffered "s/^/$(hostname) /"

消息看起来像这样：

frb.hi.inet 2015-11-17 08:39:39.432 INFO [...]

... frb.hi.inet我们主人的名字。