Conditional Index Value in output

[ccaviris89]

I was looking at this and trying to work in conditional logic on my pipeline.conf output so that if a given field exists, the index with have one values, and otherwise it will default to another value.

I currently have something like this:
output {
elasticsearch {
hosts => [ "<host_name>:<port_number>"]
index => "logstash-%{+YYYY.MM}"
}
}

I've tried a few different things, but keep getting something like:
Failed to execute action {:action=>LogStash::PipelineAction::Create/pipeline_id:main, :exception=>"LogStash::ConfigurationError", :message=>"Expected one of #, => at line 53, column 11 (byte 758) after output

[Badger]

What does the complete configuration look like, and is that the complete error message?

[ccaviris89]

That's the message. The full config looks like this:

input {
http {
}
}

filter {

json {
    source => "message"
}

mutate {
    rename => ["_duration", "duration"]
}

mutate {

    convert => {

...
several conversions
...
}

}

mutate {
    remove_field => ["headers", "message"]
}

}

output {
elasticsearch {
hosts => [ "hostName:portNumber"]
index => "logstash-%{+YYYY.MM}"
}
}