# Parsing multiline stacktrace

**URL:** <https://discuss.elastic.co/t/parsing-multiline-stacktrace/263022>\
**Category:** Logstash\
**Created:** [February 2, 2021, 6:04pm UTC](https://discuss.elastic.co/t/parsing-multiline-stacktrace/263022 "2021-02-02T18:04:34Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![RFeiten](https://avatars.discourse-cdn.com/v4/letter/r/73ab20/32.png) [@RFeiten](https://discuss.elastic.co/u/RFeiten)\
**Post date:** [February 2, 2021, 6:04pm UTC](https://discuss.elastic.co/t/parsing-multiline-stacktrace/263022/1 "2021-02-02T18:04:34Z")

</div>

Having a hard time here to index my logs containing multiple stack trace lines, as following

Here are a log sample

```auto
2021-01-04T00:47:39.6082940+00:00 0HM5E5E2861GQ:00000005 [ERR] Something went wrong:(Value cannot be null. (Parameter 'source') at System.Linq.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at ...
   at ...
   at ...
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
   at Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext httpContext)
   at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)
   at ...
2021-01-04T00:47:39.6086626+00:00 0HM5E5E2861GQ:00000005 [INF] Request finished in 517.8698ms 500 application/json (791a596a)
2021-01-04T00:47:42.5862067+00:00 0HM5E5E2861H7:00000001 [INF] Request starting HTTP/1.1 GET ... (ca22a1cb)

```

Here is the configuration grok I have in my pipeline

```auto
input {
    beats {
        port => "5044"
    }
}
filter {
    grok {
      match => { "message" => "%{TIMESTAMP_ISO8601:logdate} %{NOTSPACE:thread_id} \[%{LOGLEVEL:log.level}\] %{GREEDYDATA:msg}" }
    }
    date {
      match => ["logdate", "yyyy-MM-dd HH:mm:ss.SSSSSSSZZ", "ISO8601"] #2021-01-04T00:47:39.6082940+00:00
      target => "@timestamp"
    }
    mutate {
      remove_field => ["message", "logdate", "agent.hostname"]
    }
}

```

Here, the multiline configuration I have in my filebeat configuration. That means, I'm following the same as described here [Manage multiline messages | Filebeat Reference [7.10] | Elastic](https://www.elastic.co/guide/en/beats/filebeat/current/multiline-examples.html)

```auto
  multiline.type: pattern
  multiline.pattern: '^[[:space:]]'
  multiline.negate: false
  multiline.match: after

```

Now, when invoking the pipeline, I'm just receiving lot's of \_grokparsefailure issues, and my data goes to ElasticSearch without the expected format.

```auto
{
    "@timestamp" => 2021-02-02T17:51:30.299Z,
         "agent" => {
        "hostname" => "xxx",
            "type" => "filebeat",
         "version" => "7.10.2"
    },
           "ecs" => {},
      "@version" => "1",
          "tags" => [
        [0] "beats_input_codec_plain_applied",
        [1] "_grokparsefailure"
    ],
         "input" => {
        "type" => "log"
    },
          "host" => {
        "name" => "xxx"
    },
           "log" => {
          "file" => {
            "path" => "/var/log/Log-20210101.txt"
        },
        "offset" => 3364
    }
}

```

The idea is to make the pipeline work for both INF and ERR, independently if there are multilines or not in the middle. Any ideas?!

---

<div class="post-metadata">

**Author:** ![Badger](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/badger/32/25190_2.png) [@Badger](https://discuss.elastic.co/u/Badger)\
**Post date:** [February 2, 2021, 7:06pm UTC](https://discuss.elastic.co/t/parsing-multiline-stacktrace/263022/2 "2021-02-02T19:06:47Z")

</div>

I would suggest that you change your filters to be

```
grok {
  match => { "message" => "%{TIMESTAMP_ISO8601:logdate} %{NOTSPACE:thread_id} \[%{LOGLEVEL:log.level}\] %{GREEDYDATA:msg}" }
remove_field => ["message"]
}
date {
  match => ["logdate", "yyyy-MM-dd HH:mm:ss.SSSSSSSZZ", "ISO8601"] #2021-01-04T00:47:39.6082940+00:00
  target => "@timestamp"
  remove_field => ["logdate"]
}
mutate {
  remove_field => ["agent.hostname"]
}

```

That way the [message] field does not get removed if grok fails to parse it, and you can look at the value of the field to see why it failed.

---

<div class="post-metadata">

**Author:** ![RFeiten](https://avatars.discourse-cdn.com/v4/letter/r/73ab20/32.png) [@RFeiten](https://discuss.elastic.co/u/RFeiten)\
**Post date:** [February 2, 2021, 7:16pm UTC](https://discuss.elastic.co/t/parsing-multiline-stacktrace/263022/3 "2021-02-02T19:16:49Z")

</div>

I've got to work now, but only for the multiline occurrences. The other ones continues to give me error.

DIfference was to set the **"(?m)"** in front of the GREEDYDATA, as it can also captures multi lines. Although, still not being able to parse the single line ones...

```auto
filter {​​​​​
    grok {​​​​​
      match => {​​​​​ "message" => "%{​​​​​TIMESTAMP_ISO8601:logdate}​​​​​ %{​​​​​NOTSPACE:thread_id}​​​​​ \[%{​​​​​LOGLEVEL:log.level}​​​​​\] (?m)%{​​​​​GREEDYDATA:msg}​​​​​" }​
    }​​​​​
    date {​​​​​
      match => ["logdate", "yyyy-MM-dd HH:mm:ss.SSSSSSSZZ", "ISO8601"] #2021-01-04T00:47:39.6082940+00:00
      target => "@timestamp"
    }​​​​​
    mutate {​​​​​
      remove_field => ["logdate", "agent.hostname", "message"]
    }​​​​​
}​​​​​

```

---

<div class="post-metadata">

**Author:** ![RFeiten](https://avatars.discourse-cdn.com/v4/letter/r/73ab20/32.png) [@RFeiten](https://discuss.elastic.co/u/RFeiten)\
**Post date:** [February 2, 2021, 7:36pm UTC](https://discuss.elastic.co/t/parsing-multiline-stacktrace/263022/4 "2021-02-02T19:36:53Z")

</div>

@Badger I have implemented your suggestion, thanks for that.

By the way, I found the issue by debugging my grok with [https://grokdebug.herokuapp.com/](https://grokdebug.herokuapp.com/)

The problem was that I was using `\[%{LOGLEVEL:log.level}\]` for my log priority/level occurrences. While it accepts the values " **ERR**", it does not accept " **INF**" 😄

This is why it was only working for the multilines, because those were the ones with issues stacktrace ocurrences in fact.

To solve it, I simply changed it to `\[%{DATA:log.level}\]`

It doesn't make much sense in my opinion, but... it's working though.

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [March 2, 2021, 7:37pm UTC](https://discuss.elastic.co/t/parsing-multiline-stacktrace/263022/5 "2021-03-02T19:37:27Z")

</div>

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