Stabilize probe startup and throttled downloads

test/Nuthatch/Probe/Oidc.hs

@@ -6,6 +6,8 @@ module Nuthatch.Probe.Oidc
   , verifyPkceBoundary
   ) where
 
+import           Control.Concurrent (threadDelay)
+import           Control.Exception (SomeException, try)
 import           Data.Aeson
   ( FromJSON (..)
   , eitherDecodeStrict'
@@ -88,10 +90,12 @@ login :: ProbeContext -> Bool -> String -> String -> IO Session
 login context verifyBoundary user suffix = do
   let cookies = probeDirectory context </> "cookies-" <> suffix
       idpCookies = probeDirectory context </> "idp-" <> suffix
-  started <- curl
-    [ "--cookie-jar", cookies
-    , probeBase context <> "/login"
-    ]
+  started <-
+    retryTransport 20 $
+      curl
+        [ "--cookie-jar", cookies
+        , probeBase context <> "/login"
+        ]
   assertEqual "login redirect status" 303 (curlStatus started)
   authorizationUrl <-
     maybe (fail "login response omitted Location") (pure . B8.unpack) $
@@ -397,3 +401,14 @@ replaceAll needle replacement value =
 
 optionalEnv :: String -> IO (Maybe String)
 optionalEnv = lookupEnv
+
+retryTransport :: Int -> IO value -> IO value
+retryTransport attempts action = do
+  result <- try action
+  case result of
+    Right value -> pure value
+    Left exception
+      | attempts > 1 -> do
+          threadDelay 100000
+          retryTransport (attempts - 1) action
+      | otherwise -> fail (show (exception :: SomeException))