yesod-routes-metrics

yesod-routes-metrics provides middleware to track data for routes access. The main function is registerYesodMetrics.

Examples

• Simple app with metrics - https://github.com/plow-technologies/yesod-routes-metrics/tree/master/examples/print-routes

• Print out all metrics - https://github.com/plow-technologies/yesod-routes-metrics/tree/master/examples/yesod-with-metrics

How to use yesod-routes-metrics

module Yesod.Routes.Metrics where

registerYesodMetrics :: Bool -> Text -> ByteString -> Store -> IO YesodMetrics
registerYesodMetrics verbose namespace routesFileContents store

verbose

If True, it will create six counters per route.

/ HomeR GET

will result in six counters

getHomeR
getHomeR_response_status_1xx
getHomeR_response_status_2xx
getHomeR_response_status_3xx
getHomeR_response_status_4xx
getHomeR_response_status_5xx

otherwise if it is False it will only provide

getHomeR

which is total sum of all responses for a single path.

namespace

A string that will be appended to the name of each metric. This is useful if you have multiple servers sending data to the same source.

routesFileContents

Parse the Yesod routes file like this

import           Data.ByteString (ByteString)
import           Data.FileEmbed

routesFileContents :: ByteString
routesFileContents = $(embedFile "config/routes")

and pass it to registerYesodMetrics.

store

import System.Metrics -- ekg-core package

main = do
  ...
  store <- newStore

main

You can use forkServerWith from ekg or send data to statsd via ekg-statsd. You can also make your own custom solution.

import           System.Metrics           (newStore)
import qualified Yesod.Routes.Metrics as Yesod
import           System.Remote.Monitoring (forkServerWith) -- ekg package

main = do
  yesodMetrics <- Yesod.registerYesodMetrics True "routes" routesFileContents store
  registerGcMetrics store

  -- use this if you want to use the 
  _ <- forkServerWith store "localhost" 7000

  run 3000 (Yesod.metrics routesFileContents yesodMetrics $ app)

Types of Routes Supported

Only certain types of Yesod routes are supported by yesod-routes-metrics. To fully support Dynamic routes would require Template Haskell to build the convertMethodToRouteName function because it takes a String input and needs to reify Strings to type at compile time. You are welcome to add this functionality and make a PR.

Fully Supported

• Static routes. The example below is actually two routes: getHomeR and postHomeR.

/             HomeR     GET POST

Semi-Supported

• Dynamic single routes will be caught but no type checking is performed. Get requests to /blog/1 and /blog/hello will be counted as metrics for getBlogPostR.

/blog/#BlogId BlogPostR GET

• Overlapped Dynamic single routes will only catch the first one because there is no type checking. /foo/1 and /foo/hello will be counted as metrics for getFoo2R.

!/foo/#Int  Foo2R GET
!/foo/#Text Foo3R GET

Unsupported

• Static routes are ignored.

/static       StaticR   Static getStatic

• Dynamic multi routes are also ignored.

/wiki/*Texts WikiR GET