# Ruby error when replacing @timestamp
**URL:** https://discuss.elastic.co/t/ruby-error-when-replacing-timestamp/122917
**Category:** Logstash
**Created:** [March 7, 2018, 3:58pm UTC](https://discuss.elastic.co/t/ruby-error-when-replacing-timestamp/122917 "2018-03-07T15:58:02Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Anabella\_Cristaldi](https://discuss.elastic.co/u/Anabella_Cristaldi)
#### Post date: [March 7, 2018, 3:58pm UTC](https://discuss.elastic.co/t/ruby-error-when-replacing-timestamp/122917/1 "2018-03-07T15:58:02Z")
Hi,
I need to set the @timestamp field to date contained in another field of my log
(instead of using the default indexation time)
I tried to use the date filter pluging in combination with ruby plugin
Using this code
```
date {
match => ["ts", "yyyyMMddHHmmss"]
timezone => "UTC"
target => "ts_temp"
}
ruby {
code => "event.set('@timestamp',event.get('ts_temp'))"
}
```
I get
Ruby exception occurred: wrong argument type NilClass (expected LogStash::Timestamp)
What I'm doing wrong?
Thank you very much
Regards
Anna
---
### Author:  [@Anabella\_Cristaldi](https://discuss.elastic.co/u/Anabella_Cristaldi)
#### Post date: [March 7, 2018, 4:11pm UTC](https://discuss.elastic.co/t/ruby-error-when-replacing-timestamp/122917/2 "2018-03-07T16:11:58Z")
My fault, it is not need to use the ruby plugin, just date plugin
```
date {
match => ["ts", "yyyyMMddHHmmss"]
timezone => "UTC"
}
```
Regards
Ana
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [April 4, 2018, 4:12pm UTC](https://discuss.elastic.co/t/ruby-error-when-replacing-timestamp/122917/3 "2018-04-04T16:12:06Z")
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