# Ruby exception occurred: undefined method \`unpack1' for nil:NilClass
**URL:** https://discuss.elastic.co/t/ruby-exception-occurred-undefined-method-unpack1-for-nil-nilclass/191134
**Category:** Logstash
**Created:** [July 18, 2019, 7:15am UTC](https://discuss.elastic.co/t/ruby-exception-occurred-undefined-method-unpack1-for-nil-nilclass/191134 "2019-07-18T07:15:34Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@Nagesh\_Kumar](https://discuss.elastic.co/u/Nagesh_Kumar)
#### Post date: [July 18, 2019, 7:15am UTC](https://discuss.elastic.co/t/ruby-exception-occurred-undefined-method-unpack1-for-nil-nilclass/191134/1 "2019-07-18T07:15:34Z")
Hi,
I am trying with below logstash (7.0 version) conf file to decode base64 logs to send elasticsearch but its throwing below error -
[2019-07-17T19:01:36,791][ERROR][logstash.filters.ruby] Ruby exception occurred: undefined method `unpack1' for nil:NilClass
Logstash.conf file
input {
s3 {
access\_key\_id =\> "xxxxxxx"
bucket =\> "kinesis-datadog"
region =\> "us-east-1"
secret\_access\_key =\> "xxxxxxx8"
prefix =\> "2019/07/05"
type =\> "S3"
}
}
filter {
grok {
match =\> {"message" =\> "%{WORD:prefix} %{WORD:b64} %{WORD:suffix}"}
}
ruby {
init =\> "require 'base64'"
code =\> "event['b64\_decoded'] = Base64.decode64(event['b64']) if event.include?('b64')"
}
}
#output plugin, which has the ElasticSearch domain information
output {
elasticsearch {
hosts =\> ["[http://localhost:9200](http://localhost:9200)"]
index =\> ".kibana-%{+YYYY.MM.dd}"
codec =\> rubydebug
#user =\> "elastic"
#password =\> "elastic"
}
}
---
### Author:  [@Badger](https://discuss.elastic.co/u/Badger)
#### Post date: [July 18, 2019, 9:51am UTC](https://discuss.elastic.co/t/ruby-exception-occurred-undefined-method-unpack1-for-nil-nilclass/191134/2 "2019-07-18T09:51:12Z")
> [@Nagesh\_Kumar](#):
>
> code =\> "event['b64\_decoded'] = Base64.decode64(event['b64']) if event.include?('b64')"
If you are running logstash v7 I would not expect that to work (although I would expect a different error). You should be using the [event API](https://www.elastic.co/guide/en/logstash/current/event-api.html).
Try
```
code => "
b64 = event.get('b64')
if b64
event.set('b64_decoded', Base64.decode64(b64))
end
"
```
---
### Author:  [@Nagesh\_Kumar](https://discuss.elastic.co/u/Nagesh_Kumar)
#### Post date: [July 18, 2019, 1:24pm UTC](https://discuss.elastic.co/t/ruby-exception-occurred-undefined-method-unpack1-for-nil-nilclass/191134/3 "2019-07-18T13:24:54Z")
Thanks a lot its worked !!
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [August 15, 2019, 1:24pm UTC](https://discuss.elastic.co/t/ruby-exception-occurred-undefined-method-unpack1-for-nil-nilclass/191134/4 "2019-08-15T13:24:54Z")
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