Safe Haskell	None
Language	Haskell2010

Data.Metrics.Gauge

Description

A module representing a Gauge, which is simply an action that returns the instantaneous measure of a value for charting.

The action that provides the gauge's value may be replaced using "set", or read using "value".

gaugeExample = do
  g <- gauge $ return 1
  x <- value g
  set g $ return 2
  y <- value g
  return (x == 1 && y == 2)

Synopsis

Documentation

An instantaneous measure of a value.

Instances details

(MonadBase b m, PrimMonad b) => Value b m (Gauge b) Double Source #
Instance details Defined in Data.Metrics.Gauge Methods value :: Gauge b -> m Double Source #
(MonadBase b m, PrimMonad b) => Set b m (Gauge b) (b Double) Source #
Instance details Defined in Data.Metrics.Gauge Methods set :: Gauge b -> b Double -> m () Source #
Register (Gauge IO) Source #
Instance details Defined in Data.Metrics.Registry Methods register :: MetricRegistry IO -> Text -> IO (Gauge IO) -> IO (Maybe (Gauge IO)) Source #

Create a new gauge from the given action.

Compose multiple actions to create a ratio. Useful for graphing percentage information, e. g.

connectionUtilizationRate :: IO (Gauge IO)
connectionUtilizationRate = gauge $ ratio openConnectionCount $ return connectionPoolSize