keg

A Wall Brew infrastructure library to monitor function performance in clojure applications. wb-metrics measures the time it takes functions to execute, uses clojure/tools.logging to emit debug statements.

Dependency

Add the library to your :dependencies:

[com.wallbrew/keg "1.0.0"]

Usage

First, require keg in your namespace:

(:require [keg.core :as keg])

Then, tap the function definitions you want runtime statistics for:

(defn my-awesome-function
  [arg1 arg2]
  (+ arg1 arg2))

(keg/tap #'my-awesome-function)

This creates a hook for your function. Every time it executes, it'll log some data via clojure/tools.logging through whatever logging provider your project uses. Be sure to prefix the function name with #' otherwise you'll encounter errors that state your functions are unnamed modules in the DynamicClassLoader.

For example:

(my-awesome-function 3 5)
;=> 2020-10-28T17:21:25.959Z my-machine-id DEBUG [my-app.core/my-awesome-function] - {:function-name my-awesome-function, :runtime 1}

If you want pour extra data, you can use some of the provided formatters:

(keg/tap #'my-awesome-function keg/pour-runtime-and-args)
(my-awesome-function 3 5)
;=> 2020-10-28T17:21:25.959Z my-machine-id DEBUG [my-app.core/my-awesome-function] - {:function-name my-awesome-function, :runtime 1, :arguments [3 5]}

(keg/tap #'my-awesome-function keg/pour-runtime-args-and-return)
(my-awesome-function 3 5)
;=> 2020-10-28T17:21:25.959Z my-machine-id DEBUG [my-app.core/my-awesome-function] - {:function-name my-awesome-function, :runtime 1, :arguments [3 5], :return-value 8}

Or, you can always write your own:

(defn my-awesome-formatter
  [_function-name runtime _return & args]
  {:app-port (System/getenv "PORT")
   :runtime  runtime
   :args     args})

(keg/tap #'my-awesome-function my-awesome-formatter)
(my-awesome-function 3 5)
;=> 2020-10-28T17:21:25.959Z my-machine-id DEBUG [my-app.core/my-awesome-function] - {:app-port 8080, :runtime 1, :args [3 5]}

When writing your own formatters, please note the following:

• Arguments are always received in this order: function-name runtime function-return args
• The formatter can return text, or a map for structured logging
• Care should be used when logging arguments and/or return values in production environments
• All run times are assumed to be in milliseconds

License

Copyright © 2019-2020 - Wall Brew Co

This software is provided for free, public use as outlined in the MIT License