# Logstash Metricbeat field calculation

**URL:** https://discuss.elastic.co/t/logstash-metricbeat-field-calculation/300242
**Category:** Logstash
**Created:** [March 21, 2022, 7:09pm UTC](https://discuss.elastic.co/t/logstash-metricbeat-field-calculation/300242 "2022-03-21T19:09:05Z")
**Posts on this page:** 4
**Page:** 1

<div class="post-metadata">

### Author: ![PRASHANT\_MEHTA](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/prashant_mehta/32/101764_2.png) [@PRASHANT\_MEHTA](https://discuss.elastic.co/u/PRASHANT_MEHTA)
#### Post date: [March 21, 2022, 7:09pm UTC](https://discuss.elastic.co/t/logstash-metricbeat-field-calculation/300242/1 "2022-03-21T19:09:05Z")

</div>

## I'm implementing ruby code through logstash pipeline,Unable to get desired fields created in kibana,what would be right approach to code in order to get desired result? Want to get CPU % by adding two fileds and divide by no of cores. ex:((a+b)/n)\*100

## Below code dosen't work:

ruby {  
code =\> "  
userpct = event.get('system.cpu.user.pct')  
systempct = event.get('system.cpu.system.pct')  
cores = event.get('system.cpu.cores')  
cpuusage = (((userpct+systempct)/cores)\*100)  
if (cpuusage \> 20)  
event.set('system.cpuusage',cpuusage)  
event.set('system.cpu.status','CPUCritical')  
else  
event.set('system.cpu.status','CPUHealthy')  
end

```
				"
       }

```

* * *

Image:

 ![logs](https://us1.discourse-cdn.com/elastic/original/3X/c/3/c326eba3cb33ab8371ff364480998525b198ed2e.png)

---

<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: [March 21, 2022, 7:43pm UTC](https://discuss.elastic.co/t/logstash-metricbeat-field-calculation/300242/2 "2022-03-21T19:43:35Z")

</div>

> [@PRASHANT\_MEHTA](#):
>
> system.cpu.user.pct

See [this](https://discuss.elastic.co/t/elasticsearch-filter-syntax/254793/3) post. Try [system][cpu][user][pct]

---

<div class="post-metadata">

### Author: ![PRASHANT\_MEHTA](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/prashant_mehta/32/101764_2.png) [@PRASHANT\_MEHTA](https://discuss.elastic.co/u/PRASHANT_MEHTA)
#### Post date: [March 24, 2022, 9:58am UTC](https://discuss.elastic.co/t/logstash-metricbeat-field-calculation/300242/3 "2022-03-24T09:58:54Z")

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@Badger Thanx for your response! Tried the above way you mentioned,didn't worked.

* * *

filter  
{  
mutate { add\_field =\> { "mount.point.usage" =\> "%{[host][name]} %{[system][filesystem][mount\_point]}" } }

```
ruby {
         code => "
						  userpct = event.get([system][cpu][user][pct])
				          systempct = event.get([system][cpu][system][pct])
						  cores = event.get([system][cpu][cores])
					      cpuusage = (((userpct+systempct)/cores)*100)
                          if (cpuusage > 20)
						  event.set('system.cpuusage',cpuusage)
	                      event.set('system.cpu.status','CPUCritical')
						  else
						  event.set('system.cpu.status','CPUHealthy')
						  end
						  
				"
       }

```

## }

---

<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: [April 21, 2022, 9:58am UTC](https://discuss.elastic.co/t/logstash-metricbeat-field-calculation/300242/4 "2022-04-21T09:58:59Z")

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