logstash配置文件详解

Posted wzxmt

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 logstash pipeline 包含两个必须的元素：input和output，和一个可选元素：filter。

 从input读取事件源，（经过filter解析和处理之后），从output输出到目标存储库（elasticsearch或其他）。

技术图片

  在生产环境使用logstash，一般使用都将配置写入文件里面，然后启动logstash。

  处理nginx日志

# vim nginx_access.conf
input
    file
        path => "/var/log/nginx/access.log"
        start_position => "beginning"
        type => "nginx_access_log"
    

filter
    grok
        match => "message" => "%IPORHOST:clientip %USER:ident %USER:auth \\[%HTTPDATE:timestamp\\] \\"%WORD:verb %DATA:request HTTP/%NUMBER:httpversion\\" %NUMBER:response:int (?:-|%NUMBER:bytes:int) \\"(?:-|%DATA:referrer)\\" \\"%DATA:user_agent\\" (?:%IP:proxy|-) %DATA:upstream_addr %NUMBER:upstream_request_time:float %NUMBER:upstream_response_time:float"
        match => "message" => "%IPORHOST:clientip %USER:ident %USER:auth \\[%HTTPDATE:timestamp\\] \\"%WORD:verb %DATA:request HTTP/%NUMBER:httpversion\\" %NUMBER:response:int (?:-|%NUMBER:bytes:int) \\"%DATA:referrer\\" \\"%DATA:user_agent\\" \\"%DATA:proxy\\""
    
    if [request] 
        urldecode 
            field => "request"
        
       ruby 
           init => "@kname = [‘url_path‘,‘url_arg‘]"
           code => "
               new_event = LogStash::Event.new(Hash[@kname.zip(event.get(‘request‘).split(‘?‘))])
               event.append(new_event)"
       
        if [url_arg] 
            ruby 
               init => "@kname = [‘key‘, ‘value‘]"
               code => "event.set(‘url_args‘, event.get(‘url_arg‘).split(‘&‘).collect |i| Hash[@kname.zip(i.split(‘=‘))])"
                
        
    
    geoip
        source => "clientip"
    
    useragent
        source => "user_agent"
        target => "ua"
        remove_field => "user_agent"
    
    date 
        match => ["timestamp","dd/MMM/YYYY:HH:mm:ss Z"]
        locale => "en"
    
    mutate
        remove_field => ["message","timestamp","request","url_arg"]
    

output
    elasticsearch       
        hosts => "localhost:9200"
        index => "nginx-access-log-%+YYYY.MM.dd"   
    
#　　stdout        
#　　　　 codec => rubydebug    
#　　

 

如果是想测试配置文件写的是否正确，用下面这个方式启动测试一下

/usr/share/logstash/bin/logstash -t -f /etc/logstash/conf.d/nginx.conf  #测试配置文件
Configuration OK
/usr/share/logstash/bin/logstash -f /etc/logstash/conf.d/nginx_access.conf  #启动logstash

启动logstash

# systemctl start logstash

 input plugin  让logstash可以读取特定的事件源。

 官网：https://www.elastic.co/guide/en/logstash/current/input-plugins.html

 事件源可以是从stdin屏幕输入读取，可以从file指定的文件，也可以从es，filebeat，kafka，redis等读取

  • stdin 标准输入
  • file   从文件读取数据 
    file
    path => [‘/var/log/nginx/access.log‘]  #要输入的文件路径
    type => ‘nginx_access_log‘
    start_position => "beginning"

# path  可以用/var/log/*.log,/var/log/**/*.log，如果是/var/log则是/var/log/*.log
# type 通用选项. 用于激活过滤器
# start_position 选择logstash开始读取文件的位置，begining或者end。
还有一些常用的例如：discover_interval，exclude，sincedb_path,sincedb_write_interval等可以参考官网
  • syslog  通过网络将系统日志消息读取为事件 
    syslog
    port =>"514" 
    type => "syslog"

# port 指定监听端口(同时建立TCP/UDP的514端口的监听)

#从syslogs读取需要实现配置rsyslog：
# cat /etc/rsyslog.conf   加入一行
*.* @172.17.128.200:514　  #指定日志输入到这个端口，然后logstash监听这个端口，如果有新日志输入则读取
# service rsyslog restart   #重启日志服务
    　
  • beats   从Elastic beats接收事件 
    beats 
    port => 5044   #要监听的端口

# 还有host等选项

# 从beat读取需要先配置beat端，从beat输出到logstash。
# vim /etc/filebeat/filebeat.yml 
..........
output.logstash:
hosts: ["localhost:5044"]
  • kafka  将 kafka topic 中的数据读取为事件 
    kafka
    bootstrap_servers=> "kafka01:9092,kafka02:9092,kafka03:9092"
    topics => ["access_log"]
    group_id => "logstash-file"
    codec => "json"

    kafka
    bootstrap_servers=> "kafka01:9092,kafka02:9092,kafka03:9092"
    topics => ["weixin_log","user_log"]  
    codec => "json"

    # bootstrap_servers 用于建立群集初始连接的Kafka实例的URL列表。
    # topics  要订阅的主题列表，kafka topics
    # group_id 消费者所属组的标识符，默认为logstash。kafka中一个主题的消息将通过相同的方式分发到Logstash的group_id
# codec 通用选项，用于输入数据的编解码器。

　　　还有很多的input插件类型，可以参考官方文档来配置。

filter plugin 过滤器插件，对事件执行中间处理

  • grok   解析文本并构造 。把非结构化日志数据通过正则解析成结构化和可查询化   
    grok 
            match => "message"=>"^%IPORHOST:clientip %USER:ident %USER:auth \\[%HTTPDATE:timestamp\\] "%WORD:verb %DATA:request HTTP/%NUMBER:httpversion" %NUMBER:response:int (?:-|%NUMBER:bytes:int) %QS:referrer %QS:agent$"
        
匹配nginx日志
# 203.202.254.16 - - [22/Jun/2018:16:12:54 +0800] "GET / HTTP/1.1" 200 3700 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/601.7.7 (KHTML, like Gecko) Version/9.1.2 Safari/601.7.7"
#220.181.18.96 - - [13/Jun/2015:21:14:28 +0000] "GET /blog/geekery/xvfb-firefox.html HTTP/1.1" 200 10975 "-" "Mozilla/5.0 (compatible; Baiduspider/2.0; +http://www.baidu.com/search/spider.html)"
    技术图片
        grok 
            match => "message"=>"^%IPORHOST:clientip %USER:ident %USER:auth \\[%HTTPDATE:timestamp\\] "%WORD:verb %DATA:request HTTP/%NUMBER:httpversion" %NUMBER:response:int (?:-|%NUMBER:bytes:int) %QS:referrer %QS:agent$"
        
匹配nginx日志
# 203.202.254.16 - - [22/Jun/2018:16:12:54 +0800] "GET / HTTP/1.1" 200 3700 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/601.7.7 (KHTML, like Gecko) Version/9.1.2 Safari/601.7.7"
#220.181.18.96 - - [13/Jun/2015:21:14:28 +0000] "GET /blog/geekery/xvfb-firefox.html HTTP/1.1" 200 10975 "-" "Mozilla/5.0 (compatible; Baiduspider/2.0; +http://www.baidu.com/search/spider.html)"
    技术图片
  •  注意这里grok 可以有多个match匹配规则，如果前面的匹配失败可以使用后面的继续匹配。例如 
     grok 
            match => ["message", "%IP:clientip - %USER:user \\[%HTTPDATE:raw_datetime\\] \\"(?:%WORD:verb %URIPATHPARAM:request HTTP/%NUMBER:httpversion)\\" (?:\\"%DATA:body\\" )?(?:\\"%DATA:cookie\\" )?%NUMBER:response (?:%NUMBER:bytes:int|-) \\"%DATA:referrer\\" \\"%DATA:agent\\" (?:(%IP:proxy,? ?)*|-|unknown) (?:%DATA:upstream_addr |)%NUMBER:request_time:float (?:%NUMBER:upstream_time:float|-)"]
            match => ["message", "%IP:clientip - %USER:user \\[%HTTPDATE:raw_datetime\\] \\"(?:%WORD:verb %URI:request HTTP/%NUMBER:httpversion)\\" (?:\\"%DATA:body\\" )?(?:\\"%DATA:cookie\\" )?%NUMBER:response (?:%NUMBER:bytes:int|-) \\"%DATA:referrer\\" \\"%DATA:agent\\" (?:(%IP:proxy,? ?)*|-|unknown) (?:%DATA:upstream_addr |)%NUMBER:request_time:float (?:%NUMBER:upstream_time:float|-)"]
    技术图片
            grok 
            match => ["message", "%IP:clientip - %USER:user \\[%HTTPDATE:raw_datetime\\] \\"(?:%WORD:verb %URIPATHPARAM:request HTTP/%NUMBER:httpversion)\\" (?:\\"%DATA:body\\" )?(?:\\"%DATA:cookie\\" )?%NUMBER:response (?:%NUMBER:bytes:int|-) \\"%DATA:referrer\\" \\"%DATA:agent\\" (?:(%IP:proxy,? ?)*|-|unknown) (?:%DATA:upstream_addr |)%NUMBER:request_time:float (?:%NUMBER:upstream_time:float|-)"]
            match => ["message", "%IP:clientip - %USER:user \\[%HTTPDATE:raw_datetime\\] \\"(?:%WORD:verb %URI:request HTTP/%NUMBER:httpversion)\\" (?:\\"%DATA:body\\" )?(?:\\"%DATA:cookie\\" )?%NUMBER:response (?:%NUMBER:bytes:int|-) \\"%DATA:referrer\\" \\"%DATA:agent\\" (?:(%IP:proxy,? ?)*|-|unknown) (?:%DATA:upstream_addr |)%NUMBER:request_time:float (?:%NUMBER:upstream_time:float|-)"]
    技术图片

      grok 语法：%SYNTAX:SEMANTIC   即 %正则:自定义字段名

                     官方提供了很多正则的grok pattern可以直接使用  :https://github.com/logstash-plugins/logstash-patterns-core/blob/master/patterns  

                     grok debug工具： http://grokdebug.herokuapp.com

　　　　　　正则表达式调试工具： https://www.debuggex.com/

　　　　需要用到较多的正则知识，参考文档有：https://www.jb51.net/tools/zhengze.html

         自定义模式：   (?<字段名>the pattern)

        例如： 匹配 2018/06/27 14:00:54  

                (?<datetime>\\d\\d\\d\\d\\/\\d\\d\\/\\d\\d \\d\\d:\\d\\d:\\d\\d)

          得到结果：  "datetime": "2018/06/27 14:00:54"

 

  • date   日期解析  解析字段中的日期，然后转存到@timestamp 
    [2018-07-04 17:43:35,503]
grok
      match => "message"=>"%DATA:raw_datetime"

date
       match => ["raw_datetime","YYYY-MM-dd HH:mm:ss,SSS"]
        remove_field =>["raw_datetime"]


#将raw_datetime存到@timestamp 然后删除raw_datetime

#24/Jul/2018:18:15:05 +0800
date 
      match => ["timestamp","dd/MMM/YYYY:HH:mm:ss Z]
    技术图片
    [2018-07-04 17:43:35,503]
grok
      match => "message"=>"%DATA:raw_datetime"

date
       match => ["raw_datetime","YYYY-MM-dd HH:mm:ss,SSS"]
        remove_field =>["raw_datetime"]


#将raw_datetime存到@timestamp 然后删除raw_datetime

#24/Jul/2018:18:15:05 +0800
date 
      match => ["timestamp","dd/MMM/YYYY:HH:mm:ss Z]
    技术图片
  • mutate  对字段做处理 重命名、删除、替换和修改字段。
    • covert 类型转换。类型包括：integer，float，integer_eu，float_eu，string和boolean 
      filter
    mutate
#     covert => ["response","integer","bytes","float"]  #数组的类型转换
        convert => "message"=>"integer"
    

#测试------->

          "host" => "localhost",
       "message" => 123,    #没带“”,int类型
    "@timestamp" => 2018-06-26T02:51:08.651Z,
      "@version" => "1"

      技术图片
      filter
    mutate
#     covert => ["response","integer","bytes","float"]  #数组的类型转换
        convert => "message"=>"integer"
    

#测试------->

          "host" => "localhost",
       "message" => 123,    #没带“”,int类型
    "@timestamp" => 2018-06-26T02:51:08.651Z,
      "@version" => "1"
      技术图片
    • split   使用分隔符把字符串分割成数组 
      mutate
    split => "message"=>","

#---------->
aaa,bbb

    "@timestamp" => 2018-06-26T02:40:19.678Z,
      "@version" => "1",
          "host" => "localhost",
       "message" => [
        [0] "aaa",
        [1] "bbb"
    ]
192,128,1,100

        "host" => "localhost",
     "message" => [
      [0] "192",
      [1] "128",
      [2] "1",
      [3] "100"
 ],
  "@timestamp" => 2018-06-26T02:45:17.877Z,
    "@version" => "1"
      技术图片
      mutate
    split => "message"=>","

#---------->
aaa,bbb

    "@timestamp" => 2018-06-26T02:40:19.678Z,
      "@version" => "1",
          "host" => "localhost",
       "message" => [
        [0] "aaa",
        [1] "bbb"
    ]
192,128,1,100

        "host" => "localhost",
     "message" => [
      [0] "192",
      [1] "128",
      [2] "1",
      [3] "100"
 ],
  "@timestamp" => 2018-06-26T02:45:17.877Z,
    "@version" => "1"
      技术图片
    • merge  合并字段  。数组和字符串 ，字符串和字符串 
      filter
    mutate
        add_field => "field1"=>"value1"
    
    mutate 
          split => "message"=>"."   #把message字段按照.分割
    
    mutate
        merge => "message"=>"field1"   #将filed1字段加入到message字段
    

#--------------->
abc

       "message" => [
        [0] "abc,"
        [1] "value1"
    ],
    "@timestamp" => 2018-06-26T03:38:57.114Z,
        "field1" => "value1",
      "@version" => "1",
          "host" => "localhost"


abc,.123

       "message" => [
        [0] "abc,",
        [1] "123",
        [2] "value1"
    ],
    "@timestamp" => 2018-06-26T03:38:57.114Z,
        "field1" => "value1",
      "@version" => "1",
          "host" => "localhost"
      技术图片
      filter
    mutate
        add_field => "field1"=>"value1"
    
    mutate 
          split => "message"=>"."   #把message字段按照.分割
    
    mutate
        merge => "message"=>"field1"   #将filed1字段加入到message字段
    

#--------------->
abc

       "message" => [
        [0] "abc,"
        [1] "value1"
    ],
    "@timestamp" => 2018-06-26T03:38:57.114Z,
        "field1" => "value1",
      "@version" => "1",
          "host" => "localhost"


abc,.123

       "message" => [
        [0] "abc,",
        [1] "123",
        [2] "value1"
    ],
    "@timestamp" => 2018-06-26T03:38:57.114Z,
        "field1" => "value1",
      "@version" => "1",
          "host" => "localhost"
      技术图片
    • rename   对字段重命名 
      filter
    mutate
        rename => "message"=>"info"
    

#-------->
123

    "@timestamp" => 2018-06-26T02:56:00.189Z,
          "info" => "123",
      "@version" => "1",
          "host" => "localhost"
      技术图片
      filter
    mutate
        rename => "message"=>"info"
    

#-------->
123

    "@timestamp" => 2018-06-26T02:56:00.189Z,
          "info" => "123",
      "@version" => "1",
          "host" => "localhost"
      技术图片
    • remove_field    移除字段 
      mutate 
    remove_field => ["message","datetime"]

      mutate 
    remove_field => ["message","datetime"]
    • join  用分隔符连接数组，如果不是数组则不做处理 
      mutate
        split => "message"=>":"

mutate
        join => "message"=>","

------>
abc:123

    "@timestamp" => 2018-06-26T03:55:41.426Z,
       "message" => "abc,123",
          "host" => "localhost",
      "@version" => "1"

aa:cc

    "@timestamp" => 2018-06-26T03:55:47.501Z,
       "message" => "aa,cc",
          "host" => "localhost",
      "@version" => "1"
      技术图片
      mutate
        split => "message"=>":"

mutate
        join => "message"=>","

------>
abc:123

    "@timestamp" => 2018-06-26T03:55:41.426Z,
       "message" => "abc,123",
          "host" => "localhost",
      "@version" => "1"

aa:cc

    "@timestamp" => 2018-06-26T03:55:47.501Z,
       "message" => "aa,cc",
          "host" => "localhost",
      "@version" => "1"
      技术图片
    • gsub  用正则或者字符串替换字段值。仅对字符串有效　 
      mutate
        gsub => ["message","/","_"]   #用_替换/
    

------>
a/b/c/

      "@version" => "1",
       "message" => "a_b_c_",
          "host" => "localhost",
    "@timestamp" => 2018-06-26T06:20:10.811Z
      技术图片
          mutate
        gsub => ["message","/","_"]   #用_替换/
    

------>
a/b/c/

      "@version" => "1",
       "message" => "a_b_c_",
          "host" => "localhost",
    "@timestamp" => 2018-06-26T06:20:10.811Z
      技术图片
    • update  更新字段。如果字段不存在，则不做处理 
      mutate
        add_field => "field1"=>"value1"
    
    mutate
        update => "field1"=>"v1"
        update => "field2"=>"v2"    #field2不存在 不做处理
    
---------------->

    "@timestamp" => 2018-06-26T06:26:28.870Z,
        "field1" => "v1",
          "host" => "localhost",
      "@version" => "1",
       "message" => "a"

      技术图片
          mutate
        add_field => "field1"=>"value1"
    
    mutate
        update => "field1"=>"v1"
        update => "field2"=>"v2"    #field2不存在 不做处理
    
---------------->

    "@timestamp" => 2018-06-26T06:26:28.870Z,
        "field1" => "v1",
          "host" => "localhost",
      "@version" => "1",
       "message" => "a"
      技术图片
    • replace 更新字段。如果字段不存在，则创建 
       mutate
        add_field => "field1"=>"value1"
    
    mutate
        replace => "field1"=>"v1"
        replace => "field2"=>"v2"
    
---------------------->

       "message" => "1",
          "host" => "localhost",
    "@timestamp" => 2018-06-26T06:28:09.915Z,
        "field2" => "v2",        #field2不存在，则新建
      "@version" => "1",
        "field1" => "v1"
      技术图片
          mutate
        add_field => "field1"=>"value1"
    
    mutate
        replace => "field1"=>"v1"
        replace => "field2"=>"v2"
    
---------------------->

       "message" => "1",
          "host" => "localhost",
    "@timestamp" => 2018-06-26T06:28:09.915Z,
        "field2" => "v2",        #field2不存在，则新建
      "@version" => "1",
        "field1" => "v1"
      技术图片
  • geoip  根据来自Maxmind GeoLite2数据库的数据添加有关IP地址的地理位置的信息 
     geoip 
            source => "clientip"
            database =>"/tmp/GeoLiteCity.dat"
        
            geoip 
            source => "clientip"
            database =>"/tmp/GeoLiteCity.dat"
  • ruby    ruby插件可以执行任意Ruby代码 
    filter
    urldecode
        field => "message"
    
    ruby 
        init => "@kname = [‘url_path‘,‘url_arg‘]"
        code => " 
            new_event = LogStash::Event.new(Hash[@kname.zip(event.get(‘message‘).split(‘?‘))]) 
            event.append(new_event)"
    
    if [url_arg]
        kv
            source => "url_arg"
            field_split => "&"
            target => "url_args"
            remove_field => ["url_arg","message"]
        
    

# ruby插件
# 以？为分隔符，将request字段分成url_path和url_arg
-------------------->
www.test.com?test

       "url_arg" => "test",
          "host" => "localhost",
      "url_path" => "www.test.com",
       "message" => "www.test.com?test",  
      "@version" => "1",
    "@timestamp" =>  2018-06-26T07:31:04.887Z

www.test.com?title=elk&content=学习elk

      "url_args" => 
          "title" => "elk",
        "content" => "学习elk"
    ,
          "host" => "localhost",
      "url_path" => "www.test.com",
      "@version" => "1",
    "@timestamp" =>  2018-06-26T07:33:54.507Z
    技术图片
    filter
    urldecode
        field => "message"
    
    ruby 
        init => "@kname = [‘url_path‘,‘url_arg‘]"
        code => " 
            new_event = LogStash::Event.new(Hash[@kname.zip(event.get(‘message‘).split(‘?‘))]) 
            event.append(new_event)"
    
    if [url_arg]
        kv
            source => "url_arg"
            field_split => "&"
            target => "url_args"
            remove_field => ["url_arg","message"]
        
    

# ruby插件
# 以？为分隔符，将request字段分成url_path和url_arg
-------------------->
www.test.com?test

       "url_arg" => "test",
          "host" => "localhost",
      "url_path" => "www.test.com",
       "message" => "www.test.com?test",  
      "@version" => "1",
    "@timestamp" =>  2018-06-26T07:31:04.887Z

www.test.com?title=elk&content=学习elk

      "url_args" => 
          "title" => "elk",
        "content" => "学习elk"
    ,
          "host" => "localhost",
      "url_path" => "www.test.com",
      "@version" => "1",
    "@timestamp" =>  2018-06-26T07:33:54.507Z
    技术图片
  • urldecode    用于解码被编码的字段,可以解决URL中 中文乱码的问题 
     urldecode
        field => "message"
    

# field :指定urldecode过滤器要转码的字段,默认值是"message"
# charset(缺省): 指定过滤器使用的编码.默认UTF-8
        urldecode
        field => "message"
    

# field :指定urldecode过滤器要转码的字段,默认值是"message"
# charset(缺省): 指定过滤器使用的编码.默认UTF-8
  • kv   通过指定分隔符将字符串分割成key/value 
    kv
        prefix => "url_"   #给分割后的key加前缀
        target => "url_ags"    #将分割后的key-value放入指定字段
        source => "message"   #要分割的字段
        field_split => "&"    #指定分隔符
        remove_field => "message"
    
-------------------------->
a=1&b=2&c=3

            "host" => "localhost",
       "url_ags" => 
          "url_c" => "3",
          "url_a" => "1",
          "url_b" => "2"
    ,
      "@version" => "1",
    "@timestamp" => 2018-06-26T07:07:24.557Z

    技术图片
    kv
        prefix => "url_"   #给分割后的key加前缀
        target => "url_ags"    #将分割后的key-value放入指定字段
        source => "message"   #要分割的字段
        field_split => "&"    #指定分隔符
        remove_field => "message"
    
-------------------------->
a=1&b=2&c=3

            "host" => "localhost",
       "url_ags" => 
          "url_c" => "3",
          "url_a" => "1",
          "url_b" => "2"
    ,
      "@version" => "1",
    "@timestamp" => 2018-06-26T07:07:24.557Z
    技术图片
  • useragent 添加有关用户代理(如系列,操作系统,版本和设备)的信息 
    if [agent] != "-" 
  useragent 
    source => "agent"
    target => "ua"
    remove_field => "agent"
  

# if语句，只有在agent字段不为空时才会使用该插件
#source 为必填设置,目标字段
#target 将useragent信息配置到ua字段中。如果不指定将存储在根目录中

    技术图片
    if [agent] != "-" 
  useragent 
    source => "agent"
    target => "ua"
    remove_field => "agent"
  

# if语句，只有在agent字段不为空时才会使用该插件
#source 为必填设置,目标字段
#target 将useragent信息配置到ua字段中。如果不指定将存储在根目录中
    技术图片

logstash 比较运算符

　　等于:   ==, !=, <, >, <=, >=
　　正则:   =~, !~ (checks a pattern on the right against a string value on the left)
　　包含关系:  in, not in

　　支持的布尔运算符：and, or, nand, xor

　　支持的一元运算符: !

output plugin  输出插件，将事件发送到特定目标。

  • stdout  标准输出。将事件输出到屏幕上 
    output
    stdout
        codec => "rubydebug"
  • file   将事件写入文件 
        file 
       path => "/data/logstash/%host/application
       codec => line  format => "%message"
  • kafka  将事件发送到kafka 
        kafka
        bootstrap_servers => "localhost:9092"
        topic_id => "test_topic"  #必需的设置。生成消息的主题
  • elasticseach  在es中存储日志 
        elasticsearch 
        hosts => "localhost:9200"
        index => "nginx-access-log-%+YYYY.MM.dd"  
    
#index 事件写入的索引。可以按照日志来创建索引，以便于删旧数据和按时间来搜索日志

　补充一个codec plugin 编解码器插件

　　codec 本质上是流过滤器，可以作为input 或output 插件的一部分运行。例如上面output的stdout插件里有用到。

  • multiline codec plugin  多行合并, 处理堆栈日志或者其他带有换行符日志需要用到 
    input 
  stdin 
    codec => multiline 
      pattern => "pattern, a regexp"    #正则匹配规则，匹配到的内容按照下面两个参数处理
      negate => "true" or "false"     # 默认为false。处理匹配符合正则规则的行。如果为true，处理不匹配符合正则规则的行。
      what => "previous" or "next"    #指定上下文。将指定的行是合并到上一行或者下一行。
    
  

codec => multiline 
    pattern => "^\\s"  
    what => "previous"  

# 以空格开头的行都合并到上一行

codec => multiline 
    # Grok pattern names are valid! :)
    pattern => "^%TIMESTAMP_ISO8601 "
    negate => true
    what => "previous"

# 任何不以这个时间戳格式开头的行都与上一行合并

codec => multiline 
   pattern => "\\\\$"
   what => "next"

# 以反斜杠结尾的行都与下一行合并

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