40 lines
1.4 KiB
Haskell
40 lines
1.4 KiB
Haskell
{-# LANGUAGE NumericUnderscores #-}
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module PostgREST.Response.Performance
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( ServerTiming (..)
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, serverTimingHeader
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)
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where
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import qualified Data.ByteString.Char8 as BS
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import qualified Network.HTTP.Types as HTTP
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import Numeric (showFFloat)
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import Protolude
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-- | ServerTiming represents the timing data for a request, in seconds.
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data ServerTiming =
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ServerTiming
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{ jwt :: Maybe Double
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, parse :: Maybe Double
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, plan :: Maybe Double
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, transaction :: Maybe Double
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, response :: Maybe Double
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}
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deriving (Show)
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-- | Render the Server-Timing header from a ServerTimingData
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-- The duration precision is milliseconds, per the docs
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--
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-- >>> serverTimingHeader ServerTiming { plan=Just 0.1, transaction=Just 0.2, response=Just 0.3, jwt=Just 0.4, parse=Just 0.5}
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-- ("Server-Timing","jwt;dur=400.0, parse;dur=500.0, plan;dur=100.0, transaction;dur=200.0, response;dur=300.0")
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serverTimingHeader :: ServerTiming -> HTTP.Header
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serverTimingHeader timing =
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("Server-Timing", renderTiming)
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where
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renderMetric metric = maybe "" (\dur -> BS.concat [metric, BS.pack $ ";dur=" <> showFFloat (Just 1) (dur * 1_000) ""])
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renderTiming = BS.intercalate ", " $ (\(k, v) -> renderMetric k (v timing)) <$>
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[ ("jwt", jwt)
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, ("parse", parse)
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, ("plan", plan)
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, ("transaction", transaction)
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, ("response", response)
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]
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