# Syntax for adding tags from couchdb doc array attribute
**URL:** https://discuss.elastic.co/t/syntax-for-adding-tags-from-couchdb-doc-array-attribute/45619
**Category:** Logstash
**Created:** [March 28, 2016, 6:35pm UTC](https://discuss.elastic.co/t/syntax-for-adding-tags-from-couchdb-doc-array-attribute/45619 "2016-03-28T18:35:12Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@pagameba](https://discuss.elastic.co/u/pagameba)
#### Post date: [March 28, 2016, 6:35pm UTC](https://discuss.elastic.co/t/syntax-for-adding-tags-from-couchdb-doc-array-attribute/45619/1 "2016-03-28T18:35:12Z")
Hi, I'm trying to figure out the logstash filter syntax for mutate to add tags (using add\_tag) to an event coming from a couchdb\_changes feed where the tags need to come from a document attribute that is, itself, an array (coincidentally called tags).
The logstash configuration file looks something like this (edited for brevity and security)
```
input {
couchdb_changes {
host => "couch"
port => "5984"
db => "test"
codec => "json"
}
}
filter {
#some document attributes are turned into event attributes
mutate {
add_field => { "doc_id" => "%{[@metadata][_id]}" }
add_field => { "title" => "%{[doc][name]}" }
add_field => { "description" => "%{[doc][description]}" }
}
# several fields are used to add tags like this
if [doc][somekey] {
mutate { add_tag => ["somekey"] }
}
# How to add all the values in the doc.tags array as tags to the event?
# we don't want to store the whole doc in elasticsearch because its big.
mutate { remove_field => ["doc"] }
}
output {
stdout { codec => "rubydebug" }
elasticsearch {
hosts => "elasticsearch:9200"
document_id => "%{[@metadata][_id]}"
document_type => "%{[@metadata][type]}"
}
}
```
As noted, the couchdb document has an attribute called 'tags' which is an array of string values. I would like to add each of these values to the event using add\_tag but I cannot figure out the syntax for doing so.
I have tried something like this:
```
mutate {
add_field => { "tags" => "%{[doc][tags]}" }
split => { "tags" => "," }
}
```
before using `add_tag` elsewhere but if tags is an empty array or has just one element, then `tags` in the event becomes a string and other values get string-concatenated to it.
I also tried
```
mutate {
add_tag => ["%{[doc][tags]}" ]
}
```
which adds all the tags as a single comma-separated entry in the tags array, after which I tried using `split` but that didn't seem to fix it.
Any help on syntax here would be appreciated.
---
### Author:  [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)
#### Post date: [March 29, 2016, 5:41am UTC](https://discuss.elastic.co/t/syntax-for-adding-tags-from-couchdb-doc-array-attribute/45619/2 "2016-03-29T05:41:21Z")
I suspect you need to use a ruby filter for this.
```auto
filter {
ruby {
code => "
event['doc']['tags'].each { |t| event.tag(t) }
"
}
}
```
---
### Author:  [@pagameba](https://discuss.elastic.co/u/pagameba)
#### Post date: [March 29, 2016, 2:09pm UTC](https://discuss.elastic.co/t/syntax-for-adding-tags-from-couchdb-doc-array-attribute/45619/3 "2016-03-29T14:09:08Z")
This worked perfectly, thank you sooo much!
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 5:04am UTC](https://discuss.elastic.co/t/syntax-for-adding-tags-from-couchdb-doc-array-attribute/45619/4 "2017-07-06T05:04:55Z")