Multiple Elasticsearch outputs in logstash

gistfile1.txt

#http://pastebin.com/xGt6vv9R from yardenbar
output {
    if [type] == "postfix" {
        elasticsearch {
            host     => [ "ES_HOSTNAME" ]
            protocol => "transport"
            cluster  => "elasticsearch"
            index    => "postfix-%{+YYYY.MM.dd}"
            manage_template => true
            template_overwrite => true
            template => "/etc/logstash/templates.d/postfix.json"
            template_name => "postfix"
        }
    }
    else if [type] in ["nginx", "nginx_error"] {
        elasticsearch {
            host     => [ "ES_HOSTNAME" ]
            protocol => "transport"
            cluster  => "elasticsearch"
            index    => "nginx-%{+YYYY.MM.dd}"
            manage_template => true
            template_overwrite => true
            template => "/etc/logstash/templates.d/nginx.json"
            template_name => "nginx"
        }
    }
    else if [type] == "rails" {
        elasticsearch {
            host     => [ "ES_HOSTNAME" ]
            protocol => "transport"
            cluster  => "elasticsearch"
            index    => "rails-%{+YYYY.MM.dd}"
            manage_template => true
            template_overwrite => true
            template => "/etc/logstash/templates.d/rails.json"
            template_name => "rails"
        }
    }
    else if [type] == "webpagetest" {
        elasticsearch {
            host     => [ "ES_HOSTNAME" ]
            protocol => "transport"
            cluster  => "elasticsearch"
            index    => "webpagetest-global"
            manage_template => true
            template_overwrite => true
            template => "/etc/logstash/templates.d/webpagetest.json"
            template_name => "webpagetest"
        }
    }
    else if [type] == "push-notification" {
        elasticsearch {
            host     => [ "ES_HOSTNAME" ]
            protocol => "transport"
            cluster  => "elasticsearch"
            index    => "push-notification-%{+YYYY.MM.dd}"
            manage_template => true
            template_overwrite => true
            template => "/etc/logstash/templates.d/push_notification.json"
            template_name => "push_notification"
        }
    }
    else if [type] == "fastly" {
        elasticsearch {
            host     => [ "ES_HOSTNAME" ]
            protocol => "transport"
            cluster  => "elasticsearch"
            index    => "fastly-%{+YYYY.MM.dd}"
            manage_template => true
            template_overwrite => true
            template => "/etc/logstash/templates.d/fastly.json"
            template_name => "fastly"
        }
    }
    else {
        file {
            path => "/var/log/logstash/unknown_messages.log"
        }
    }
}

If you don't want to have the type fields in the documents that are output, you can also consider adding metadata which will be used for driving data to different outputs, and removing the 'type' fields. I have written a blog post that demonstrates this approach at https://alexmarquardt.com/2018/08/31/using-logstash-to-drive-filtered-data-from-a-single-source-into-multiple-output-destinations/.