Metrics Plugin: Meter vs. Timer?

What's the difference between meter and timer? I can find any info on it. Can you provide examples of when one would be used over the other?

Meters are counters of the number of events, e.g. the number of HTTP 404s. Timers are for durations and include min/max/mean/stddev/percentiles, useful for e.g. the durations of HTTP requests.

Thanks for answering. So, if I wanted to capture the durations of HTTP requests, I would have to pass it in to the second parameter ( e.g. timer => ["http_metric_name", "%{http_duration_value}"] ) ?

Yes.