Grokparsefailure when %{TIMESTAMP_ISO8601} pattern is in the first position parser

Hi Elastic Team,

I have a issue when in my grok filter y put first the pattern %{TIMESTAMP_ISO8601}. I share a example:

With %{TIMESTAMP_ISO8601} at first position:


grok Debugger:

I got [1] "_grokparsefailure"

With %{TIMESTAMP_ISO8601} at second position:


grok Debugger:

I got my parser without any problem:

I apreciate your feedback, thanks.

You need to show us the value of [message] that you are matching against.

Please do not post images of text, just post the text itself.

Hi Badger,

Messsage with TIMESTAMP_ISO8601 first: 2021-07-09 15:23:30.000 Adixon
Messsage with TIMESTAMP_ISO8601 second: Adixon 2021-07-09 15:23:30.000


input { generator { count => 1 lines => [ '2021-07-09 15:23:30.000 Adixon' ] } }
filter {
    grok { match => { "message" => "%{TIMESTAMP_ISO8601:date} %{WORD:test}" } }


      "date" => "2021-07-09 15:23:30.000",
      "test" => "Adixon",

so I suspect [message] does not contain what you think it does.

You're totally right Badger, my problem is the source, i use NXLOG for bring date to logstash, and when i search the timestamp i see:

 "Message" => "9044436 Adixon"

I mean the timestamp i recived but in number "9044436".

I think that i should see what happen in NXLOG.

Hi team,

As solution, how Badger said, the key was see the message field. I see that the first caracter of the message always came different, example:

The field that i was looking: [7/12/21 15:40:58:862 CLT]
The field that i recieved: 7/12/21 15:40:58:862 CLT]


The field that i was looking: 2021-07-09 18:47:30.000 ERROR Adixon
The field that i recieved: 02021-07-09 18:47:30.000 ERROR Adixon

In both cases the first caracter changed and next i just was more carefully seeing first how message came and adapting my grok filter.