remove unused imports

src/PaymentServer/Processors/Stripe.hs

@@ -18,14 +18,10 @@ import Control.Exception
   ( try
   , throwIO
   )
-import Data.ByteString
-  ( ByteString
-  )
 import Data.Text
   ( Text
   , unpack
   )
-import qualified Data.Map as Map
 import Text.Read
   ( readMaybe
   )
@@ -41,8 +37,6 @@ import Data.Aeson
 import Servant
   ( Server
   , Handler
-  , err400
-  , err500
   , ServerError(ServerError, errHTTPCode, errBody, errHeaders, errReasonPhrase)
   , throwError
   )
@@ -51,22 +45,12 @@ import Servant.API
   , JSON
   , Post
   , (:>)
-  , (:<|>)((:<|>))
-  )
-import Web.Stripe.Event
-  ( Event(Event, eventId, eventType, eventData)
-  , EventId(EventId)
-  , EventType(ChargeSucceededEvent)
-  , EventData(ChargeEvent)
   )
 import Web.Stripe.Types
   ( Charge(Charge, chargeMetaData)
   , MetaData(MetaData)
   , Currency
   )
-import Web.Stripe.Error
-  ( StripeError(StripeError)
-  )
 import Web.Stripe.Charge
   ( createCharge
   , Amount(Amount)
@@ -79,6 +63,9 @@ import Web.Stripe
   ( stripe
   , (-&-)
   )
+
+import qualified Prometheus as P
+
 import PaymentServer.Persistence
   ( Voucher
   , VoucherDatabase(payForVoucher)
@@ -126,10 +113,19 @@ instance FromJSON Charges where
                          v .: "currency"
   parseJSON _ = mzero
 
+chargeAttempts :: P.Counter
+chargeAttempts
+  = P.unsafeRegister
+  $ P.counter
+  $ P.Info "charge_attempts" "The number of attempted charge requests received."
+
 -- | call the stripe Charge API (with token, voucher in metadata, amount, currency etc
 -- and if the Charge is okay, then set the voucher as "paid" in the database.
 charge :: VoucherDatabase d => StripeConfig -> d -> Charges -> Handler Acknowledgement
 charge stripeConfig d (Charges token voucher amount currency) = do
+
+  liftIO $ P.incCounter chargeAttempts
+
   currency' <- getCurrency currency
   result <- liftIO (try (payForVoucher d voucher (completeStripeCharge currency')))
   case result of