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Get time-out-resilience by using req HTTP client
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Replace `http-client` with `req` and use all the sweet retry
functionality from `req`. `req` uses a Fibonacci sequence to back off.
This also lets us remove loads of code.

Close #93.
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@Rembane
Rembane committed Sep 27, 2023
1 parent 176c75c commit 25da699
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Showing 6 changed files with 58 additions and 139 deletions.
9 changes: 3 additions & 6 deletions app/Main.hs
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Original file line number Diff line number Diff line change
Expand Up @@ -30,7 +30,6 @@ import Data.Time.Format ( defaultTimeLocale
import Lens.Micro.Platform ( set
, view
)
import Network.HTTP.Client.TLS ( newTlsManager )
import Network.Wai.Middleware.RequestLogger ( logStdout )
import Network.Wai.Middleware.StaticEmbedded ( static )
import System.Console.GetOpt ( ArgDescr(..)
Expand All @@ -50,7 +49,6 @@ import Web.Scotty ( get

import Config
import Model
import Model.Types ( ClientContext(..) )
import View ( render )

opts :: [OptDescr (Config -> Config)]
Expand All @@ -73,7 +71,6 @@ main = (reifyConfig . getOpt Permute opts <$> getArgs) >>= \case
(Config { _cHelp = True }, _ , _ ) -> usage
(config , _ , _ ) -> do
upd <- newEmptyMVar -- putMVar when to update
mgr <- newTlsManager
viewRef <- createViewReference

-- In the list there are three items running concurrently:
Expand All @@ -84,17 +81,17 @@ main = (reifyConfig . getOpt Permute opts <$> getArgs) >>= \case
Async.Concurrently
[ timer upd config
, webserver config viewRef upd
, updater mgr upd viewRef config
, updater upd viewRef config
]
where
timer upd cfg =
forever $ tryPutMVar upd () >> threadDelay (view cInterval cfg)

updater mgr upd viewRef cfg =
updater upd viewRef cfg =
forever
$ withFDHandler defaultBatchingOptions stdout 1.0 80
$ \logCallback -> runLoggingT
(runReaderT (refresh viewRef upd) (ClientContext cfg mgr))
(runReaderT (refresh viewRef upd) cfg)
( logCallback
. renderWithTimestamp
(formatTime defaultTimeLocale (iso8601DateFormat (Just "%H:%M:%S")))
Expand Down
8 changes: 5 additions & 3 deletions mat-chalmers.cabal
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Original file line number Diff line number Diff line change
Expand Up @@ -34,14 +34,14 @@ library
, css-text
, exceptions == 0.10.4
, heredoc == 0.2.0.0
, http-client
, http-client-tls == 0.3.5.3
, logging-effect == 1.3.12
, microlens-platform
, lucid >= 2
, mtl == 2.2.2
, old-locale == 1.0.0.7
, prettyprinter == 1.7.1
, req == 3.9.0
, retry == 0.8.1.2
, safe == 0.3.19
, tagsoup == 0.14.8
, text == 1.2.4.1
Expand All @@ -57,11 +57,13 @@ executable mat-chalmers
build-depends: mat-chalmers
, base >= 4.7
, bytestring
, exceptions
, file-embed
, http-client-tls == 0.3.5.3
, microlens-platform
, logging-effect
, mtl
, prettyprinter
, req
, scotty
, time == 1.9.3
, wai-extra
Expand Down
33 changes: 20 additions & 13 deletions src/Model.hs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
{-# LANGUAGE FlexibleContexts, OverloadedStrings #-}
{-# LANGUAGE FlexibleContexts, NumericUnderscores, OverloadedStrings #-}
module Model
( Restaurant(..)
, Menu(..)
Expand All @@ -23,12 +23,17 @@ import Control.Monad.Log ( MonadLog
import Control.Monad.Reader ( MonadReader
, asks
)
import Control.Retry ( fibonacciBackoff
, limitRetries
)
import Data.IORef ( IORef
, newIORef
, writeIORef
)
import Data.Foldable ( for_ )
import Data.Text.Lazy ( pack )
import Data.Text.Lazy ( fromStrict
, pack
)
import Prettyprinter ( Doc
, pretty
)
Expand All @@ -45,12 +50,12 @@ import Lens.Micro.Platform ( (^.)
, (%~)
, view
)
import Network.HTTP.Req

import Config
import Model.Types
import Model.Karen
import Model.Wijkanders
import Util

-- | Refreshes menus.
-- The refresh function evaluates to `Some monad m => m (View model, Update signal)`,
Expand All @@ -60,7 +65,7 @@ refresh
:: ( Monad m
, MonadIO m
, MonadLog (WithTimestamp (Doc ann)) m
, MonadReader ClientContext m
, MonadReader Config m
, MonadThrow m
)
=> IORef View -> MVar () -> m ()
Expand All @@ -78,29 +83,31 @@ createViewReference = liftIO $ do
update
:: ( MonadIO m
, MonadLog (WithTimestamp (Doc ann)) m
, MonadReader ClientContext m
, MonadReader Config m
, MonadThrow m
)
=> m View
update = do
c <- asks ccCfg
dateNow <- liftIO $ fmap (view _zonedTimeToLocalTime) getZonedTime
nextDayHour <- asks _cNextDayHour
dateNow <- liftIO $ fmap (view _zonedTimeToLocalTime) getZonedTime
let (textday, d) =
if (dateNow ^. (_localTimeOfDay . _todHour)) >= view cNextDayHour c
if dateNow ^. _localTimeOfDay . _todHour >= nextDayHour
then
("Tomorrow", dateNow & (_localDay . gregorian . _ymdDay) %~ (+ 1))
else ("Today", dateNow)
let day' = d ^. _localDay
let karenR = fetchAndCreateRestaurant day'
rest <- sequence
rest <- runReq (
defaultHttpConfig {
httpConfigRetryPolicy = fibonacciBackoff 30_000_000 <> limitRetries 5
}) $ sequence
[ karenR "K\229rrestaurangen"
"karrestaurangen"
"21f31565-5c2b-4b47-d2a1-08d558129279"
, karenR "S.M.A.K." "smak" "3ac68e11-bcee-425e-d2a8-08d558129279"
, karenR "L's Kitchen" "ls-kitchen" "c74da2cf-aa1a-4d3a-9ba6-08d5569587a1"
, fmap
(Restaurant "Wijkanders" (pack wijkandersAPIURL) . (>>= getWijkanders day'))
(safeGetBS wijkandersAPIURL)
, Restaurant "Wijkanders" (fromStrict $ renderUrl wijkandersAPIURL) .
getWijkanders day' . responseBody <$> req GET wijkandersAPIURL NoReqBody lbsResponse mempty
]

for_ rest $ \r -> case menu r of
Expand All @@ -110,4 +117,4 @@ update = do

return (View rest textday d)
where
wijkandersAPIURL = "http://www.wijkanders.se/restaurangen/"
wijkandersAPIURL = http "www.wijkanders.se" /: "restaurangen"
70 changes: 29 additions & 41 deletions src/Model/Karen.hs
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Original file line number Diff line number Diff line change
Expand Up @@ -10,14 +10,11 @@ where
import Control.Monad ( (>=>) )
import Control.Monad.Catch ( MonadThrow )
import Control.Monad.IO.Class ( MonadIO )
import Control.Monad.Reader ( MonadReader )
import Data.Aeson ( object
, (.=)
, encode
, (.:)
, withArray
, withObject
, eitherDecode
, Value
)
import Data.Aeson.Types ( Parser
Expand All @@ -26,33 +23,24 @@ import Data.Aeson.Types ( Parser
import Data.Bifunctor ( first )
import qualified Data.ByteString.Lazy.Char8 as BL8
import Data.Foldable ( find )
import Data.Functor ( (<&>) )
import Data.Text.Lazy ( Text
, unpack
)
import Data.Thyme.Calendar ( Day
, showGregorian
)
import Network.HTTP.Client ( RequestBody(..)
, method
, parseRequest
, requestBody
, requestHeaders
)
import Network.HTTP.Req
import Text.Heredoc ( str )

import Model.Types ( ClientContext(..)
, NoMenu(..)
import Model.Types ( NoMenu(..)
, Menu(..)
, Restaurant
( Restaurant
)
)
import Util ( menusToEitherNoLunch
, safeBS
)
import Util ( menusToEitherNoLunch )

apiURL :: String
apiURL = "https://plateimpact-heimdall.azurewebsites.net/graphql"

-- brittany-disable-next-binding
graphQLQuery :: String
Expand Down Expand Up @@ -82,18 +70,19 @@ type Language = String

-- | Fetch a menu from Kårens GraphQL API.
fetch
:: (MonadIO m, MonadReader ClientContext m, MonadThrow m)
=> String -- ^ RestaurantUUID
-> Day -- ^ Day
-> m (Either NoMenu BL8.ByteString) -- ^ Either a bytestring payload or a NoMenu error
fetch restaurantUUID day = do
initialRequest <- parseRequest apiURL
safeBS
(initialRequest { method = "POST"
, requestBody = RequestBodyLBS $ encode requestData
, requestHeaders = [("Content-Type", "application/json")]
}
)
:: (MonadHttp m, MonadIO m, MonadThrow m)
=> String -- ^ RestaurantUUID
-> Day -- ^ Day
-> m Value -- ^ A JSON response or horrible crash
fetch restaurantUUID day =
req
POST
(https "plateimpact-heimdall.azurewebsites.net" /: "graphql")
(ReqBodyJson requestData)
jsonResponse
mempty
<&> responseBody

where
requestData = object
[ "query" .= graphQLQuery
Expand All @@ -108,18 +97,17 @@ fetch restaurantUUID day = do
-- | Parses menus from Kåren's GraphQL API.
parse
:: Language -- ^ Language
-> BL8.ByteString -- ^ Bytestring payload from fetch
-> Either NoMenu [Menu] -- ^ Either list of parsed Menu's or NoMenu error
-> Value -- ^ JSON result from `fetch`
-> Either NoMenu [Menu] -- ^ Either list of parsed `Menu`s or `NoMenu` error
parse lang =
failWithNoMenu eitherDecode
>=> failWithNoMenu
(parseEither
( withObject "Parse meals"
$ (.: "data")
>=> (.: "dishOccurrencesByTimeRange")
>=> mapM menuParser
)
)
failWithNoMenu
(parseEither
( withObject "Parse meals"
$ (.: "data")
>=> (.: "dishOccurrencesByTimeRange")
>=> mapM menuParser
)
)
>=> menusToEitherNoLunch
where
failWithNoMenu :: Show a => (a -> Either String b) -> a -> Either NoMenu b
Expand All @@ -145,7 +133,7 @@ parse lang =

-- | Fetch a restaurant from Kåren's GraphQL API
fetchAndCreateRestaurant
:: (MonadIO m, MonadReader ClientContext m, MonadThrow m)
:: (MonadHttp m, MonadIO m, MonadThrow m)
=> Day -- ^ Day
-> Text -- ^ Title
-> Text -- ^ Tag
Expand All @@ -159,4 +147,4 @@ fetchAndCreateRestaurant day title tag uuid =
<> "/"
<> uuid
)
<$> fmap (parse "Swedish" =<<) (fetch (unpack uuid) day)
<$> fmap (parse "Swedish") (fetch (unpack uuid) day)
12 changes: 0 additions & 12 deletions src/Model/Types.hs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,3 @@
{-# LANGUAGE FlexibleContexts #-}

-- | Types and internal functions

Expand All @@ -7,16 +6,6 @@ module Model.Types where
import Data.ByteString.Lazy ( ByteString )
import Data.Text.Lazy ( Text )
import Data.Thyme ( LocalTime )
import Network.HTTP.Client ( HttpException
, Manager
)

import Config ( Config )

data ClientContext = ClientContext
{ ccCfg :: Config
, ccManager :: Manager
}

-- | What to pass to template.
data View = View
Expand All @@ -34,7 +23,6 @@ data Restaurant = Restaurant

data NoMenu
= NoLunch
| NMHttp HttpException
| NMParseError String ByteString -- ^ The parse error. The string we tried to parse.
deriving (Show)

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