Logstash - Output - Http - Message

[rguerrero (Roberto Guerrero)]

The next pipeline work good.

input {
  jdbc {
    jdbc_driver_library => "C:\\03_ELK\\logstash\\drivers\\ojdbc6-11.2.0.3.jar"
    jdbc_driver_class => "Java::oracle.jdbc.driver.OracleDriver"
    jdbc_connection_string => "jdbc:oracle:thin:@XXXXXXXXXXXXXX:1521:orcl"
    jdbc_user => "XXXXXXXXXXXXX"
    jdbc_password => "XXXXXXXXXXXXXXXXXXXXX"
    parameters => { }
    #schedule => "*/5 * * * * UTC" #cada 5 mins comprobada
    schedule => "* * * * * UTC"    #cada 1 min
    statement => "select XXXXXXXXXXXXXX FROM XXXXXXXXXXXXXXX where rownum = 1"
  }
}

filter {
  if [%{tx_nombre}]=="pedro"{
    mutate { add_field => { "**alert**" => "juan,cpu.id=0 1000" } }
  }
 }

output{
       http {
       format => "message"
       http_method =>"post"
       content_type => "text/plain"
       request_timeout => 120
       url => "https://xxxxxxxxxxxxxxx.live.dynatrace.com/api/v2/metrics/ingest?api-token=xxxxxxxxxxxxx"
       pool_max => 1000
       connect_timeout => 30
       message => "juan,cpu.id=0 1000"
    }
    stdout { codec => rubydebug }
}

but I change the line: message => "%{alert}"

My output failet; It is not recognizing the value or perhaps the field that I added alert
Show me the following error: Encountered non-2xx HTTP code 400 {

I tried the following in my output: tx_nombre = pedro

Not work: #message => "[%{tx_nombre}],[%{tx_nombre}]=0 100"
Work: #message => "pedro,pedro=0 100"

---

Not work: message => "[%{tx_nombre}]"
Not work: message => "tx_nombre"

How can I concatenate this value in the message http output, additional in the filter I am adding a field ut not work