How will create a global variable in logstash?

Hello,

My config is like this -

input{
http_poller{
// here I have mentioned API url and authorisation
tags => ["tag1"]
}
http_poller{
// here I have mentioned API url and authorisation
tags => ["tag2"]
}
http_poller{
// here I have mentioned API url and authorisation
tags => ["tag3"]
}
}
filter { 
  mutate {
	remove_field => [ "[message]" ]
	remove_field => [ "[@version]" ]
	remove_field => [ "[@timestamp]" ]
	remove_field => [ "[event]" ]
  }
}
output{
if "tag1" in tags
{
elasticsearch{
//elastic credentials and index name
}
}
if "tag2" in tags
{
elasticsearch{
//elastic credentials and index name
}
}
if "tag3" in tags
{
elasticsearch{
//elastic credentials and index name
}
}
}

Here Api Credentials and Elastic credentials are same for all the tags. So, I want to use a global variable so that I can use it in the configuration.

P.s: I dont want to use environment variable. Is there any other way to do that???