1. Steve Losh
  2. metrics-clojure


metrics-clojure / docs / source / title-desugaring.rst

Title Desugaring by the def[metric] Macros

All of the def[metric] macros (:ref:`defcounter <counters/defcounter>`, :ref:`defgauge <gauges/defgauge>`, :ref:`defhistogram <histograms/defhistogram>`, :ref:`defmeter <meters/defmeter>`, and :ref:`deftimer <timers/deftimer>`) take a title as their first argument.

All of the macros will use this title as a symbol when binding it to a var, and will convert it to a string to use as the :ref:`name <metric-names>` of the metric.

For example, this:

(defmeter post-requests)

is equivalent to:

(def post-requests (meter "post-requests"))

If you want to define a metric with a name outside of the default group/type, you can use a vector of three strings and/or symbols instead of a bare symbol. The last entry in the vector will be used as the symbol for the var (and will be coerced if necessary). For example, all of these:

(defcounter ["mysite.http" api post-requests])
(defcounter ["mysite.http" "api" post-requests])
(defcounter ["mysite.http" "api" "post-requests"])

are equivalent to:

(def post-requests (meter ["mysite.http" "api" "post-requests"]))

If you need more control than this (e.g.: if you want a var named differently than the last segment of the metric name) you should use the normal creation methods. These macros are only a bit of syntactic sugar to reduce typing.