logstash json和rubydebug 第次重启logstash都会把所有的日志读完 而不是只读入新输入的内容

查看一下agent端的shipper的配置：

# cat logstash_test2.shipper.conf
input {
    file {
        path => ["/apps/logstash/conf/test/test2_log.txt"]
        start_position => "beginning"
        sincedb_path => "/dev/null"
     }
 }
output {
    stdout {
        #codec => rubydebug
        codec => json
     }
 }
#这个测试主要是看输出的格式为json的

先简测一下刚配好的shipper：

# ./../bin/logstash -f logstash_test2.shipper.conf -t
Sending Logstash's logs to /apps/logstash/logs which is now configured via log4j2.properties
Configuration OK
[--08T18::,][INFO ][logstash.runner          ] Using config.test_and_exit mode. Config Validation Result: OK. Exiting Logstash

可以看到没有报错，接下来启动logstash并指定刚才配置好的配置文件：

# ./../bin/logstash -f logstash_test2.shipper.conf -t
Sending Logstash's logs to /apps/logstash/logs which is now configured via log4j2.properties
Configuration OK
[--08T18::,][INFO ][logstash.runner          ] Using config.test_and_exit mode. Config Validation Result: OK. Exiting Logstash
[root@Appsrv130 conf]# ./../bin/logstash -f logstash_test2.shipper.conf
Sending Logstash's logs to /apps/logstash/logs which is now configured via log4j2.properties
[--08T18::,][INFO ][logstash.pipeline        ] Starting pipeline {"id"=>"main", "pipeline.workers"=>, "pipeline.batch.size"=>, "pipeline.batch.delay"=>, "pipeline.max_inflight"=>}
[--08T18::,][INFO ][logstash.pipeline        ] Pipeline main started
[--08T18::,][INFO ][logstash.agent           ] Successfully started Logstash API endpoint {:port=>}
{"path":"/apps/logstash/conf/test/test2_log.txt","@timestamp":"2016-12-08T10:19:13.102Z","@version":"","host":"ofs1","message":"haha------>","tags":[]}{"path":"/apps/logstash/conf/test/test2_log.txt","@timestamp":"2016-12-08T10:19:13.113Z","@version":"","host":"ofs1","message":"haha------>2","tags":[]}{"path":"/apps/logstash/conf/test/test2_log.txt","@timestamp":"2016-12-08T10:19:13.118Z","@version":"","host":"ofs1","message":"haha------>3","tags":[]}{"path":"/apps/logstash/conf/test/test2_log.txt","@timestamp":"2016-12-08T10:19:13.121Z","@version":"","host":"ofs1","message":"haha------>3","tags":[]}

再看看所监控的log日志的内容：

# cat test/test2_log.txt
haha------>
haha------>
haha------>
haha------>

发现 这个shipper启动的时候会从头到尾，把配置文件全读一边（这种效里也是从配置文件中配置好的）

再看一下这个配置文件：

# cat logstash_test2.shipper.conf
input {
    file {
        path => ["/apps/logstash/conf/test/test2_log.txt"]
        start_position => "beginning"
        sincedb_path => "/dev/null"
     }
 }
output {
    stdout {
        #codec => rubydebug
        codec => json
     }
 }
#要点就是这行sincedb_path =>"/dev/null"了！该参数用来指定sincedb文件名，但是如果我们设置为/dev/null这个linux系统上特殊的空洞文件，
那么logstash每次重启进程的时候，尝试读取sincedb内容，都只会读到空洞，也就可以理解为前不有过运行记录，自然就从初始位置开始读取了！

下面往监控文件里写入内容时，会发生下面变化：

# echo "查看json格式是什么输出－－－－－－－》">>test/test2_log.txt 

再看一下输出的内容：

# ./../bin/logstash -f logstash_test2.shipper.conf -t
Sending Logstash's logs to /apps/logstash/logs which is now configured via log4j2.properties
Configuration OK
[--08T18::,][INFO ][logstash.runner          ] Using config.test_and_exit mode. Config Validation Result: OK. Exiting Logstash
[root@Appsrv130 conf]# ./../bin/logstash -f logstash_test2.shipper.conf
Sending Logstash's logs to /apps/logstash/logs which is now configured via log4j2.properties
[--08T18::,][INFO ][logstash.pipeline        ] Starting pipeline {"id"=>"main", "pipeline.workers"=>, "pipeline.batch.size"=>, "pipeline.batch.delay"=>, "pipeline.max_inflight"=>}
[--08T18::,][INFO ][logstash.pipeline        ] Pipeline main started
[--08T18::,][INFO ][logstash.agent           ] Successfully started Logstash API endpoint {:port=>}
{"path":"/apps/logstash/conf/test/test2_log.txt","@timestamp":"2016-12-08T10:19:13.102Z","@version":"","host":"ofs1","message":"haha------>","tags":[]}{"path":"/apps/logstash/conf/test/test2_log.txt","@timestamp":"2016-12-08T10:19:13.113Z","@version":"","host":"ofs1","message":"haha------>2","tags":[]}{"path":"/apps/logstash/conf/test/test2_log.txt","@timestamp":"2016-12-08T10:19:13.118Z","@version":"","host":"ofs1","message":"haha------>3","tags":[]}{"path":"/apps/logstash/conf/test/test2_log.txt","@timestamp":"2016-12-08T10:19:13.121Z","@version":"","host":"ofs1","message":"haha------>3","tags":[]}{"path":"/apps/logstash/conf/test/test2_log.txt","@timestamp":"2016-12-08T11:17:45.060Z","@version":"","host":"ofs1","message":"查看json格式是什么输出－－－－－－－》","tags":[]}

修改配置文件：

# cat logstash_test2.shipper.conf
input {
    file {
        path => ["/apps/logstash/conf/test/test2_log.txt"]
        start_position => "beginning"
        sincedb_path => "/dev/null"
     }
 }
output {
    stdout {
        codec => rubydebug　#查看这种格式的日志输出
        #codec => json
     }
 }

查看日志:

# echo "查看rubydebug格式是什么输出－－－－－－－》">>test/test2_log.txt 

# ./../bin/logstash -f logstash_test2.shipper.conf
Sending Logstash's logs to /apps/logstash/logs which is now configured via log4j2.properties
[--08T19::,][INFO ][logstash.pipeline        ] Starting pipeline {"id"=>"main", "pipeline.workers"=>, "pipeline.batch.size"=>, "pipeline.batch.delay"=>, "pipeline.max_inflight"=>}
[--08T19::,][INFO ][logstash.pipeline        ] Pipeline main started
[--08T19::,][INFO ][logstash.agent           ] Successfully started Logstash API endpoint {:port=>}
{
          "path" => "/apps/logstash/conf/test/test2_log.txt",
    "@timestamp" => --08T11::.290Z,
      "@version" => "",
          "host" => "ofs1",
       "message" => "haha------>",
          "tags" => []
}
{
          "path" => "/apps/logstash/conf/test/test2_log.txt",
    "@timestamp" => --08T11::.299Z,
      "@version" => "",
          "host" => "ofs1",
       "message" => "haha------>2",
          "tags" => []
}
{
          "path" => "/apps/logstash/conf/test/test2_log.txt",
    "@timestamp" => --08T11::.301Z,
      "@version" => "",
          "host" => "ofs1",
       "message" => "haha------>3",
          "tags" => []
}
{
          "path" => "/apps/logstash/conf/test/test2_log.txt",
    "@timestamp" => --08T11::.302Z,
      "@version" => "",
          "host" => "ofs1",
       "message" => "haha------>3",
          "tags" => []
}
{
          "path" => "/apps/logstash/conf/test/test2_log.txt",
    "@timestamp" => --08T11::.303Z,
      "@version" => "",
          "host" => "ofs1",
       "message" => "查看json格式是什么输出－－－－－－－》",
          "tags" => []
}
{
          "path" => "/apps/logstash/conf/test/test2_log.txt",
    "@timestamp" => --08T11::.415Z,
      "@version" => "",
          "host" => "ofs1",
       "message" => "查看rubydebug格式是什么输出－－－－－－－》",
          "tags" => []
}

如果去掉上面的两个参数，看一下效果:

# cat logstash_test2.shipper.conf
input {
    file {
        path => ["/apps/logstash/conf/test/test2_log.txt"]
        #start_position => "beginning"
        #sincedb_path => "/dev/null"
     }
 }
output {
    stdout {
        codec => rubydebug
        #codec => json
     }
 }

从另一个shell可以看到效果：

# ./../bin/logstash -f logstash_test2.shipper.conf
Sending Logstash's logs to /apps/logstash/logs which is now configured via log4j2.properties
[--09T13::,][INFO ][logstash.pipeline        ] Starting pipeline {"id"=>"main", "pipeline.workers"=>, "pipeline.batch.size"=>, "pipeline.batch.delay"=>, "pipeline.max_inflight"=>}
[--09T13::,][INFO ][logstash.pipeline        ] Pipeline main started
[--09T13::,][INFO ][logstash.agent           ] Successfully started Logstash API endpoint {:port=>}

先导入数据:

echo '去掉参数start_position => "beginning" sincedb_path => "/dev/null"' >>test/test2_log.txt 

下面看一下效果:

# ./../bin/logstash -f logstash_test2.shipper.conf
Sending Logstash's logs to /apps/logstash/logs which is now configured via log4j2.properties
[--09T13::,][INFO ][logstash.pipeline        ] Starting pipeline {"id"=>"main", "pipeline.workers"=>, "pipeline.batch.size"=>, "pipeline.batch.delay"=>, "pipeline.max_inflight"=>}
[--09T13::,][INFO ][logstash.pipeline        ] Pipeline main started
[--09T13::,][INFO ][logstash.agent           ] Successfully started Logstash API endpoint {:port=>}
{
          "path" => "/apps/logstash/conf/test/test2_log.txt",
    "@timestamp" => --09T05::.155Z,
      "@version" => "",
          "host" => "ofs1",
       "message" => "去掉参数start_position => \"beginning\" sincedb_path => \"/dev/null\"",
          "tags" => []
}