Fields added when input is file, but not when input is filebeats

Elastic Stack Logstash
1

Hi,
I'm reading some weird log files and managed to extract the information I want using grok and kv. However, at the end I want to replace the message field with a simpler message, using fields from the grok plugin. When I use the file input for tests, everything works. When I switch the input to filebeats, the replace does not work and the message gets the literal names of the fields used.

A log entry example:

2019-05-15 23:41:50, ==================================================================================
2019-05-15 23:41:50, - Server sent a new telegram ---
2019-05-15 23:41:50, ---- Telegramtype TEST_TELEGRAM--- 599 ---
2019-05-15 23:41:50, ---- Returkod = 0 ---
2019-05-15 23:41:50, ---- Finished TEST_TELEGRAM ---

Logstash config:

# Filebeats -> Logstash -> Elasticsearch pipeline.
input {
  file {
    path => "c:/users/myuser/Downloads/ELK/7.2.0/logstash-7.2.0/bin/logstash-tests2.log"
    sincedb_path => "nul"
    start_position => "beginning"
    codec => multiline {
      pattern => "^%[0-9]{4}-[0-9]{2}-[0-9]{2} [0-9]{2}:[0-9]{2}:[0-9]{2}, %{WORD:}"
      negate => true
      what => "previous"
    }
  }

  # beats {
  #   port => 5044
  # }
}

filter {

  # ECS. Copy the original message to the log.original field
  mutate {
    copy => { "message" => "log.original" }
  }

  # Extract timestamp
  grok {
    match => [ "message", "(?m)%{TIMESTAMP_ISO8601:timestamp}%{GREEDYDATA:message}" ]
    overwrite => [ "message" ]
  }

  date {
    match => [ "timestamp" , "yyyy-MM-dd HH:mm:ss" ]
  }

  # Clean up
  mutate {
    gsub => [
      "message", "^[0-9]{4}-[0-9]{2}-[0-9]{2} [0-9]{2}:[0-9]{2}:[0-9]{2}", "",
      "message", "^, ---- ", "",
      "message", "^, - ", "",
      "message", "  ---", "---",
      "message", "\r\n", "",
      "message", "^, ==================================================================================", "",
      "message", " = ", "=",
      "message", "HEADERDATA_UT:  ", ""      
    ]
  }

  # Trim message
  mutate {
     strip => [ "message" ]
  }

  # Get information to be used later in the message header (message + telegram type + number)
  grok {
    match => { "message" => "%{DATA:[@metadata][msg1]}%{SPACE}---Telegramtype %{WORD:[@metadata][telegram_type]}%{SPACE}(?<dummy>\-+)%{SPACE}%{NUMBER:[@metadata][telegram_num]}%{GREEDYDATA}"}
    
  }

  # Breakdown key-value pairs
  kv {
    field_split_pattern => "---"
    target => "kv"
    transform_key => "lowercase"
    remove_char_key => "\ (\-)+"
  }

  # Replace the big message with a smaller one (message header). Return code will be hopefuly extracted as key-value pair (kv.returkod key) from the message.
  mutate {
    replace => { "message" => "%{[@metadata][msg1]} - Telegram type: %{[@metadata][telegram_type]}; Telegram number: %{[@metadata][telegram_num]}; Return Code: %{[kv][returkod]}" }
  }
}

output {
  elasticsearch {
    hosts => ["http://localhost:9200"]
    index => "%{[@metadata][beat]}-%{[@metadata][version]}-%{+YYYY.MM.dd}"
  }

  stdout {
    codec => rubydebug
  }
}

The resulting message field when the input is file is:

May 15, 2019 @ 23:41:50.000 Server sent a new telegram - Telegram type: TEST_TELEGRAM; Telegram number: 599; Return Code: 0

But when I switch to filebeat as the input to logstash, I get this in Kibana:

May 15, 2019 @ 23:41:50.000 %{[@metadata][msg1]} - Telegram type: %{[@metadata][telegram_type]}; Telegram number: %{[@metadata][telegram_num]}; Return Code: 0

This is driving me crazy, I'm on it for days already and no clues about what could be happening. Any ideas are very appreciated! :slight_smile:

Thanks!

2

That will occur because the fields under [@metadata] do not exist, which means the grok did not work. However, you have deleted the most important clue, which is the original value of the message field that you tried to grok. Copy it to another field, then take a look at it on the JSON tab in Kibana.

Are you doing the multiline matching in filebeat? Are you sure it is working?

3

Hi! Thanks for the reply. I finally realized what was going on. When using Filebeat input, it (filebeat) is sending my multi line log entries adding "\n" (literal) to each line end. This is a bit weird and I was expecting at least "\r\n" (I'm on Windows). Then, as you said, my grok filter was failing and that was why the variables were not being added to the event :slight_smile:
Thanks again.

4

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