logstash 学习小记

标签（空格分隔）： 日志收集

Introduce

Logstash is a tool for managing events and logs. You can use it to collect logs, parse them, and store them for
later use (like, for searching). – http://logstash.net

自从2013年logstash被ES公司收购之后，ELK stask正式称为官方用语，很多公司都开始ELK实践，我们也不例外，借用新浪是如何分析处理32亿条实时日志的？的一张图

这是一个再常见不过的架构了：
（1）Kafka：接收用户日志的消息队列。
（2）Logstash：做日志解析，统一成JSON输出给Elasticsearch。
（3）Elasticsearch：实时日志分析服务的核心技术，一个schemaless，实时的数据存储服务，通过index组织数据，兼具强大的搜索和统计功能。
（4）Kibana：基于Elasticsearch的数据可视化组件，超强的数据可视化能力是众多公司选择ELK stack的重要原因。

但是众多log 收集framwork，像flume，scribe，fluent，为什么选用logstash呢？

原因很简单：

1. 部署启动很容易，只需要有jdk就OK了
2. 配置简单，无需编码

3. 支持收集log路径的正则表达式，不像flume那样必须写死要收集的文件名，logstash不是，像这样

   path => [“/var/log/.log“]

   有个Flume VS Fluentd VS Logstash可以看看

Logstash Examples

logstash事件处理流程氛围三个stages：input ，filter，output。input支持很多，如file，redis，kafka等等，filter主要是对input的log进行自己想要的处理，output则是输出到你要存储log的第三方framework，如kafka，redis，elasticsearch，db什么的，具体的查看官网。
废话不多说，开始例子：
1. 最最简单的例子
input和output都是标准输入输出

[joeywen@192 logstash]$ bin/logstash -e ‘input { stdin { } } output { stdout {}}‘

Logstash startup completed
>hello world  ## 输入的内容
>2015-08-02T05:26:55.564Z joeywens-MacBook-Pro.local hello world   ## logstash收集的内容

1. 编写config文件

input {
  file {
    path => ["/var/log/*.log"]
    type => "syslog"
    codec => multiline {
      pattern => "(^\d+\serror)|(^.+Exception:.+)|(^\s+at .+)|(^\s+... \d+ more)|(^\s*Causedby:.+)"
      what => "previous"
    }
  }
}


output {
  stdout {  codec => rubydebug }
  #  elasticsearch {
  #      host => ‘localhost‘
  #      protocol => ‘transport‘
  #      cluster => ‘elasticsearch‘
 #       index => ‘logstash-joeymac-%{+YYYY.MM.dd}‘
 #   }
}

输入是file形式，收集系统日志，如果有异常发生，通常异常会多行，这里用codec ＝> multiline 来对出现异常的多行转换为一行输入

输出就是ES，或者你也可以把stdout作为调试打开看看，输出的是什么内容。运行命令如下以及输出

[joeywen@192 logstash]$ bin/logstash -f sys.conf
Logstash startup completed

{
    "@timestamp" => "2015-08-02T05:36:08.972Z",
       "message" => "Aug  2 13:36:08 joeywens-MacBook-Pro.local GoogleSoftwareUpdateAgent[1976]: 2015-08-02 13:34:51.764 GoogleSoftwareUpdateAgent[1976/0xb029b000] [lvl=2] -[KSUpdateEngine(PrivateMethods) updateFinish] KSUpdateEngine update processing complete.",
      "@version" => "1",
          "host" => "joeywens-MacBook-Pro.local",
          "path" => "/var/log/system.log",
          "type" => "syslog"
}
{
    "@timestamp" => "2015-08-02T05:36:08.973Z",
       "message" => "Aug  2 13:36:08 joeywens-MacBook-Pro.local GoogleSoftwareUpdateAgent[1976]: 2015-08-02 13:36:08.105 GoogleSoftwareUpdateAgent[1976/0xb029b000] [lvl=3] -[KSAgentUploader fetcher:failedWithError:] Failed to upload stats to <NSMutableURLRequest https://tools.google.com/service/update2> with error Error Domain=NSURLErrorDomain Code=-1001 \"The request timed out.\" UserInfo=0x3605f0 {NSErrorFailingURLStringKey=https://tools.google.com/service/update2, _kCFStreamErrorCodeKey=60, NSErrorFailingURLKey=https://tools.google.com/service/update2, NSLocalizedDescription=The request timed out., _kCFStreamErrorDomainKey=1, NSUnderlyingError=0x35fd30 \"The request timed out.\"}",
      "@version" => "1",
          "host" => "joeywens-MacBook-Pro.local",
          "path" => "/var/log/system.log",
          "type" => "syslog"
}
{
    "@timestamp" => "2015-08-02T05:36:08.973Z",
       "message" => "Aug  2 13:36:08 joeywens-MacBook-Pro.local GoogleSoftwareUpdateAgent[1976]: 2015-08-02 13:36:08.272 GoogleSoftwareUpdateAgent[1976/0xb029b000] [lvl=3] -[KSAgentApp uploadStats:] Failed to upload stats <KSStatsCollection:0x4323e0 path=\"/Users/joeywen/Library/Google/GoogleSoftwareUpdate/Stats/Keystone.stats\", count=6, stats={",
      "@version" => "1",
          "host" => "joeywens-MacBook-Pro.local",
          "path" => "/var/log/system.log",
          "type" => "syslog"
}

如果想添加或删除字段，该怎么办？filter就该登场了

1. filter
   filter的功能十分强大，可以对input的内容做任何更改，input的内容会转换为一个叫event的map，里面存放着key／value对，正如你所看到的输出一样，@timestamp,type,@version, host,message等等，都是event里面的key，在filter里面你可以启动ruby 编程plugin对其做任何更改
   如：

input {
  file {
    path => ["/var/log/*.log"]
    type => "syslog"
    codec => multiline {
      pattern => "(^\d+\serror)|(^.+Exception:.+)|(^\s+at .+)|(^\s+... \d+ more)|(^\s*Causedby:.+)"
      what => "previous"
    }
  }
}

filter {

    if [type] =~ /^syslog/ {
        ruby {
            code => "file_name = event[‘path‘].split(‘/‘)[-1]
            event[‘file_name‘] = file_name"
        }
    }
}

output {
  stdout {  codec => rubydebug }
 }

如上我对type已syslog开头的event做更改，调用ruby编程
看看输出

[joeywen@192 logstash]$ bin/logstash -f sys.conf
Logstash startup completed
{
    "@timestamp" => "2015-08-02T05:46:52.771Z",
       "message" => "Aug  2 13:46:40 joeywens-MacBook-Pro.local Dock[234]: CGSConnectionByID: 0 is not a valid connection ID.",
      "@version" => "1",
          "host" => "joeywens-MacBook-Pro.local",
          "path" => "/var/log/system.log",
          "type" => "syslog",
     "file_name" => "system.log"
}

可以看到多了个file_name的字段，
如果相对message做解析的话，需要调用grok plugin来做，grok是很强大插件,例如

input {
  file {
    path => "/var/log/http.log"
  }
}
filter {
  grok {
    patterns_dir => ["/opt/logstash/patterns", "/opt/logstash/extra_patterns"]
    match => { "message" => "%{IP:client} %{WORD:method} %{URIPATHPARAM:request} %{NUMBER:bytes} %{NUMBER:duration}" }
  }
}

对于message字段调用正则匹配，语法是%{SYNTAX:SEMANTIC}
第一个SYNTAX是正则表达式名称，第二个是对于匹配成功的字段取名字，这些SYNTAX存在指定的pattern_dir目录下的文件，格式是：

NAME PATTERN
如 NUMBER \d+

也可以使用mutate来最event的key和value做更改，包括remove，add，update,rename 等等，具体的都可以看看(logstash文档)[https://www.elastic.co/guide/en/logstash/current/plugins-filters-mutate.html]

这里给个具体的例子吧
配置：

input {
  file {
    path => ["/var/log/*.log"]
    type => "syslog"
    codec => multiline {
      pattern => "(^\d+\serror)|(^.+Exception:.+)|(^\s+at .+)|(^\s+... \d+ more)|(^\s*Causedby:.+)"
      what => "previous"
    }
  }
}

filter {

    if [type] =~ /^syslog/ {
        ruby {
            code => "file_name = event[‘path‘].split(‘/‘)[-1]
            event[‘file_name‘] = file_name"
        }
        grok {
            patterns_dir => ["./patterns/*"]
            match => {"message" => "%{MAC_BOOK:joeymac}"}
        }

        mutate {
            rename => {"file_name" => "fileName"}
            add_field => {"foo_%{joeymac}" => "Hello world, from %{host}"}
        }
    }
}

output {
  stdout {  codec => rubydebug }
 }

输出

[joeywen@192 logstash]$ bin/logstash -f sys.conf
Logstash startup completed
{
                  "@timestamp" => "2015-08-02T06:10:13.161Z",
                     "message" => "Aug  2 14:10:12 joeywens-MacBook-Pro com.apple.xpc.launchd[1] (com.apple.quicklook[2206]): Endpoint has been activated through legacy launch(3) APIs. Please switch to XPC or bootstrap_check_in(): com.apple.quicklook",
                    "@version" => "1",
                        "host" => "joeywens-MacBook-Pro.local",
                        "path" => "/var/log/system.log",
                        "type" => "syslog",
                     "joeymac" => "joeywens-MacBook-Pro",
                    "fileName" => "system.log",
    "foo_joeywens-MacBook-Pro" => "Hello world, from joeywens-MacBook-Pro.local"
}

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