logstash multiline 按数字开头合并

[elk@node01 conf]$ cat t7.conf 
input {
    file {
                type => "viewip"
                path => ["/home/elk/conf/cccc.txt"]
                start_position=>"beginning"
                
        }
    
}
filter {
  multiline {  
  pattern => "^[0-9]"
  negate=>true  
  what=>"previous"  
 }  
}

output {
     elasticsearch {
                hosts => "192.168.137.2:9200"
                index => "logstash-viewip-%{+YYYY.MM.dd}"
        }
   stdout {
   codec=>rubydebug{}
 }
}

[elk@node01 conf]$ cat cccc.txt 
1.1.1.1
aaaaaaa
bbbbbbb
2.2.2.2
ccccccc
ddddddd
3.3.3.3
eeeeeee
fffffff
4.4.4.4
ggggggg
hhhhhhh
5.5.5.5
iiiiiii
jjjjjjj
kkkkkkk

[elk@node01 conf]$ logstash -f t7.conf 
Settings: Default pipeline workers: 4
Defaulting pipeline worker threads to 1 because there are some filters that might not work with multiple worker threads {:count_was=>4, :filters=>["multiline"], :level=>:warn}
Pipeline main started
{
       "message" => "1.1.1.1
aaaaaaa
bbbbbbb",
      "@version" => "1",
    "@timestamp" => "2018-07-31T02:31:33.540Z",
          "path" => "/home/elk/conf/cccc.txt",
          "host" => "node01",
          "type" => "viewip",
          "tags" => [
        [0] "multiline"
    ]
}
{
       "message" => "2.2.2.2
ccccccc
ddddddd",
      "@version" => "1",
    "@timestamp" => "2018-07-31T02:31:35.294Z",
          "path" => "/home/elk/conf/cccc.txt",
          "host" => "node01",
          "type" => "viewip",
          "tags" => [
        [0] "multiline"
    ]
}
{
       "message" => "3.3.3.3
eeeeeee
fffffff",
      "@version" => "1",
    "@timestamp" => "2018-07-31T02:31:35.296Z",
          "path" => "/home/elk/conf/cccc.txt",
          "host" => "node01",
          "type" => "viewip",
          "tags" => [
        [0] "multiline"
    ]
}
{
       "message" => "4.4.4.4
ggggggg
hhhhhhh",
      "@version" => "1",
    "@timestamp" => "2018-07-31T02:31:35.309Z",
          "path" => "/home/elk/conf/cccc.txt",
          "host" => "node01",
          "type" => "viewip",
          "tags" => [
        [0] "multiline"
    ]
}
{
       "message" => "5.5.5.5
iiiiiii
jjjjjjj
kkkkkkk
",
      "@version" => "1",
    "@timestamp" => "2018-07-31T02:31:35.319Z",
          "path" => "/home/elk/conf/cccc.txt",
          "host" => "node01",
          "type" => "viewip",
          "tags" => [
        [0] "multiline"
    ]
}