# Time Diff Calculation in ruby not working
**URL:** https://discuss.elastic.co/t/time-diff-calculation-in-ruby-not-working/167775
**Category:** Logstash
**Created:** [February 10, 2019, 11:23pm UTC](https://discuss.elastic.co/t/time-diff-calculation-in-ruby-not-working/167775 "2019-02-10T23:23:27Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@ssasporta](https://discuss.elastic.co/u/ssasporta)
#### Post date: [February 10, 2019, 11:23pm UTC](https://discuss.elastic.co/t/time-diff-calculation-in-ruby-not-working/167775/1 "2019-02-10T23:23:27Z")
Hi,
**What is wrong in the following filter lines that I am not able to find the TimeDiff field in the output?**
```
date {
match => ["Criado em", "dd/MM/yyyy HH:mm:ss", "ISO8601"]
target => "CreateDate"
}
date {
match => ["Data de Fechamento", "dd/MM/yyyy HH:mm:ss", "ISO8601"]
target => "ClosedDate"
}
if [ClosedDate] =~ /.+/ {
ruby {
init => "require 'time'"
code => "
starttime = Time.iso8601(event.get('CreateDate').to_s).to_f;
endtime = Time.iso8601(event.get('ClosedDate').to_s).to_f;
event.set('TimeDiff', endtime - starttime);
"
}
}
```
**I can see in the Kibana, in the created index:**
ClosedDate September 22nd 2018, 02:00:00.000
CreateDate September 14th 2018, 20:07:39.000
Regards,
Sharon.
---
### Author:  [@Badger](https://discuss.elastic.co/u/Badger)
#### Post date: [February 10, 2019, 11:37pm UTC](https://discuss.elastic.co/t/time-diff-calculation-in-ruby-not-working/167775/2 "2019-02-10T23:37:53Z")
> [@ssasporta](#):
>
> if [ClosedDate] =~ /.+/ {
This is a regexp match on a Logstash::TimeStamp object. It does not do what you want, so the ruby filter is not run. You might want
```
if [ClosedDate] {
```
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [March 10, 2019, 11:37pm UTC](https://discuss.elastic.co/t/time-diff-calculation-in-ruby-not-working/167775/3 "2019-03-10T23:37:57Z")
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