把字符串转换为整型

/********* 把字符串转换成整型
zjtest7-frontend:/usr/local/logstash-2.3.4/config# cat geoip.conf
input {stdin {} }

filter {
  geoip {
   source =>"message"
  add_field => [ "[geoip][scantest]", "%{[geoip][location][0]}" ]
 }
  mutate {  
                        convert => [ "[geoip][region_name]", "integer"]  
                }  
} 


output {
      stdout {
               codec => rubydebug{}
                } 
}


zjtest7-frontend:/usr/local/logstash-2.3.4/config# ../bin/logstash -f geoip.conf
Settings: Default pipeline workers: 1
Pipeline main started
115.218.62.240
{
       "message" => "115.218.62.240",
      "@version" => "1",
    "@timestamp" => "2016-09-11T04:25:13.291Z",
          "host" => "0.0.0.0",
         "geoip" => {
                      "ip" => "115.218.62.240",
           "country_code2" => "CN",
           "country_code3" => "CHN",
            "country_name" => "China",
          "continent_code" => "AS",
             "region_name" => 2,
               "city_name" => "Wenzhou",
                "latitude" => 27.99940000000001,
               "longitude" => 120.66680000000002,
                "timezone" => "Asia/Shanghai",
        "real_region_name" => "Zhejiang",
                "location" => [
            [0] 120.66680000000002,
            [1] 27.99940000000001
        ],
                "scantest" => 120.66680000000002
    }
}


缺省:
zjtest7-frontend:/usr/local/logstash-2.3.4/config# cat geoip.conf
input {stdin {} }

filter {
  geoip {
   source =>"message"
  add_field => [ "[geoip][scantest]", "%{[geoip][location][0]}" ]
 }
#  mutate {  
#                        convert => [ "[geoip][region_name]", "integer"]  
#                }  
} 


output {
      stdout {
               codec => rubydebug{}
                } 
}

zjtest7-frontend:/usr/local/logstash-2.3.4/config# ../bin/logstash -f geoip.conf
Settings: Default pipeline workers: 1
Pipeline main started
115.218.62.240
{
       "message" => "115.218.62.240",
      "@version" => "1",
    "@timestamp" => "2016-09-11T04:26:55.758Z",
          "host" => "0.0.0.0",
         "geoip" => {
                      "ip" => "115.218.62.240",
           "country_code2" => "CN",
           "country_code3" => "CHN",
            "country_name" => "China",
          "continent_code" => "AS",
             "region_name" => "02",
               "city_name" => "Wenzhou",
                "latitude" => 27.99940000000001,
               "longitude" => 120.66680000000002,
                "timezone" => "Asia/Shanghai",
        "real_region_name" => "Zhejiang",
                "location" => [
            [0] 120.66680000000002,
            [1] 27.99940000000001
        ],
                "scantest" => 120.66680000000002
    }
}