# Is there a way to alter the value of live API data polled using http\_poller input plugin?
**URL:** https://discuss.elastic.co/t/is-there-a-way-to-alter-the-value-of-live-api-data-polled-using-http-poller-input-plugin/142671
**Category:** Logstash
**Created:** [August 2, 2018, 3:21am UTC](https://discuss.elastic.co/t/is-there-a-way-to-alter-the-value-of-live-api-data-polled-using-http-poller-input-plugin/142671 "2018-08-02T03:21:04Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@APJ](https://discuss.elastic.co/u/APJ)
#### Post date: [August 2, 2018, 3:21am UTC](https://discuss.elastic.co/t/is-there-a-way-to-alter-the-value-of-live-api-data-polled-using-http-poller-input-plugin/142671/1 "2018-08-02T03:21:05Z")
Hi all,
I have a logstash config file that pulls in live data using the http\_poller plugin. Here is my logstash.conf
```
input {
http_poller {
urls => {
weather => {
url => "http://api.openweathermap.org/data/2.5/weather?id=5490223&appid="MY_APP_ID"&units=metric"
headers => {
Accept => "application/json"
}
}
}
schedule => { cron => "* * * * * *" }
codec => json
}
}
filter {
mutate {
remove_field => ["@version" ,"command" ,"host" ,"cod" ,"id" ,"base" ,"coord" ,"sys" ,"dt"]
}
split { field => "weather" }
}
output {
elasticsearch {
hosts => ["localhost:9200"]
index => "weather"
}
stdout {
codec => rubydebug
}
}
```
I want to modify the data retrieved from openweathermap every 30 seconds before sending it into elasticsearch. Is there a way to do it?
I would really appreciate if someone could help me out. Thanks!
---
### Author:  [@NerdSec](https://discuss.elastic.co/u/NerdSec)
#### Post date: [August 2, 2018, 4:13am UTC](https://discuss.elastic.co/t/is-there-a-way-to-alter-the-value-of-live-api-data-polled-using-http-poller-input-plugin/142671/2 "2018-08-02T04:13:54Z")
> [@APJ](#):
>
> I want to modify the data retrieved from openweathermap every 30 seconds before sending it into elasticsearch. Is there a way to do it?
What do you mean by modify? Could you give an example?
---
### Author:  [@APJ](https://discuss.elastic.co/u/APJ)
#### Post date: [August 2, 2018, 4:50am UTC](https://discuss.elastic.co/t/is-there-a-way-to-alter-the-value-of-live-api-data-polled-using-http-poller-input-plugin/142671/3 "2018-08-02T04:50:18Z")
Hi NerdSec,
The `http://api.openweathermap.org/data/2.5/weather?id=5490223&appid="MY_APP_ID"&units=metric` API gives me a lot of data (fields), like temperature, humdity, pressure, etc.
For instance, I want to alter the actual temperature value polled in by logstash, and then send that value to elasticsearch.
Let's assume the main.temp is 20ºF. Now, I want logstash to make it 30ºF and send that data to elasticsearch
So, I'd like to know if there is a way to do this. Please help me out here.
---
### Author:  [@NerdSec](https://discuss.elastic.co/u/NerdSec)
#### Post date: [August 2, 2018, 5:27am UTC](https://discuss.elastic.co/t/is-there-a-way-to-alter-the-value-of-live-api-data-polled-using-http-poller-input-plugin/142671/4 "2018-08-02T05:27:59Z")
Hi,
You can do arithmetic operations using the ruby filter. Here are some links.
> **[Event API | Logstash Reference \[8.11\] | Elastic](https://www.elastic.co/guide/en/logstash/current/event-api.html)**
> [@Doing mathematical ops using logstash filters](https://discuss.elastic.co/t/doing-mathematical-ops-using-logstash-filters/30058/2):
>
> if 'time\_duration' \< '500' { mutate { add\_tag =\> ["FAST"] } Two problems: Fields are referred via the square bracket notation, i.e. [time\_duration] in this case. You need fields to be integers (or doubles) for numerical comparisons to work. See below. I am using haproxy config, which I don't think I need to print here. But for reference, the bytes\_read and the time\_duration are INT types. No, they're strings. That's obvious from the stdout output. The fact that a grok expression use…
> [@Math operations with ruby](https://discuss.elastic.co/t/math-operations-with-ruby/55140):
>
> I want to multiply or divide two fields and create a new field based on that. I've got this ruby code: ruby { code =\> "event['hit\_rate'] = event['MAIN\_client\_req'] \* event['MAIN\_cache\_hit']" } When I try to use it I'm getting: Ruby exception occurred: undefined method `\*' for nil:NilClass {:level=\>:error} Ruby exception occurred: NilClass can't be coerced into Fixnum {:level=\>:error} This is a part of my logstash config: grok { match =\> { "message" =\> "(?\
Regards,
NerdSec
---
### Author:  [@APJ](https://discuss.elastic.co/u/APJ)
#### Post date: [August 2, 2018, 7:02am UTC](https://discuss.elastic.co/t/is-there-a-way-to-alter-the-value-of-live-api-data-polled-using-http-poller-input-plugin/142671/5 "2018-08-02T07:02:31Z")
Thanks a lot NerdSec!
My goal is to perform addition operation on `main.temp` value (main.temp = main.temp + 10) every 30 seconds. Elasticsearch is something new to me. So I would be grateful if you could let me know what exactly needs to be added or changed in the logstash.conf.
Regards,
APJ
---
### Author:  [@NerdSec](https://discuss.elastic.co/u/NerdSec)
#### Post date: [August 2, 2018, 5:57pm UTC](https://discuss.elastic.co/t/is-there-a-way-to-alter-the-value-of-live-api-data-polled-using-http-poller-input-plugin/142671/6 "2018-08-02T17:57:19Z")
I am not sure how to do it for every 30 sec. As far as I am aware, the said filter will run for every event, irrespective of time.
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [August 30, 2018, 5:57pm UTC](https://discuss.elastic.co/t/is-there-a-way-to-alter-the-value-of-live-api-data-polled-using-http-poller-input-plugin/142671/7 "2018-08-30T17:57:20Z")
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