[server] allow feature flags to be overwritten by env vars

PR-URL: https://github.com/hasura/graphql-engine-mono/pull/7659
Co-authored-by: Gil Mizrahi <8547573+soupi@users.noreply.github.com>
GitOrigin-RevId: 2a64ff09118aa0b5cbf494c45e4b178de366236b

server/lib/api-tests/src/Test/API/Metadata/NativeAccessSpec.hs

@@ -19,24 +19,27 @@ import Test.Hspec (SpecWith, describe, it)
 -- We currently don't need the table to exist in order to set up a custom SQL
 -- stanza.
 
+featureFlagForNativeQuery :: String
+featureFlagForNativeQuery = "HASURA_FF_NATIVE_QUERY_INTERFACE"
+
 spec :: SpecWith GlobalTestEnvironment
 spec =
-  Fixture.run
-    ( NE.fromList
-        [ (Fixture.fixture $ Fixture.Backend Postgres.backendTypeMetadata)
-            { Fixture.setupTeardown = \(testEnv, _) ->
-                [ Postgres.setupTablesAction [] testEnv
-                ],
-              Fixture.customOptions =
-                Just $
-                  Fixture.defaultOptions
-                    { Fixture.skipTests =
-                        Just "Disabled until we can dynamically switch on Native Access with a command line option in NDAT-452"
-                    }
-            }
-        ]
-    )
-    tests
+  Fixture.hgeWithEnv [(featureFlagForNativeQuery, "True")] $
+    Fixture.run
+      ( NE.fromList
+          [ (Fixture.fixture $ Fixture.Backend Postgres.backendTypeMetadata)
+              { Fixture.setupTeardown = \(testEnv, _) ->
+                  [ Postgres.setupTablesAction [] testEnv
+                  ],
+                Fixture.customOptions =
+                  Just $
+                    Fixture.defaultOptions
+                      { Fixture.skipTests = Just "Skipped until we merge the implementation"
+                      }
+              }
+          ]
+      )
+      tests
 
 -- ** Setup and teardown
 

server/lib/test-harness/src/Harness/GraphqlEngine.hs

@@ -326,7 +326,7 @@ runApp serveOptions = do
           liftIO $ createServerMetrics $ EKG.subset ServerSubset store
         pure (EKG.subset EKG.emptyOf store, serverMetrics)
     prometheusMetrics <- makeDummyPrometheusMetrics
-    runManagedT (App.initialiseServerCtx env globalCtx serveOptions Nothing serverMetrics prometheusMetrics sampleAlways FeatureFlag.defaultValueIO) $ \serverCtx@ServerCtx {..} ->
+    runManagedT (App.initialiseServerCtx env globalCtx serveOptions Nothing serverMetrics prometheusMetrics sampleAlways (FeatureFlag.checkFeatureFlag env)) $ \serverCtx@ServerCtx {..} ->
       do
         let Loggers _ _ pgLogger = scLoggers
         flip App.runPGMetadataStorageAppT (scMetadataDbPool, pgLogger)
@@ -340,7 +340,7 @@ runApp serveOptions = do
               initTime
               Nothing
               ekgStore
-              FeatureFlag.defaultValueIO
+              (FeatureFlag.checkFeatureFlag env)
 
 -- | Used only for 'runApp' above.
 data TestMetricsSpec name metricType tags

server/src-exec/Main.hs

@@ -69,7 +69,7 @@ runApp env (HGEOptions rci metadataDbUrl hgeCmd) = do
       -- It'd be nice if we didn't have to call runManagedT twice here, but
       -- there is a data dependency problem since the call to runPGMetadataStorageApp
       -- below depends on serverCtx.
-      runManagedT (initialiseServerCtx env globalCtx serveOptions Nothing serverMetrics prometheusMetrics sampleAlways FeatureFlag.defaultValueIO) $ \serverCtx@ServerCtx {..} -> do
+      runManagedT (initialiseServerCtx env globalCtx serveOptions Nothing serverMetrics prometheusMetrics sampleAlways (FeatureFlag.checkFeatureFlag env)) $ \serverCtx@ServerCtx {..} -> do
         -- Catches the SIGTERM signal and initiates a graceful shutdown.
         -- Graceful shutdown for regular HTTP requests is already implemented in
         -- Warp, and is triggered by invoking the 'closeSocket' callback.
@@ -87,7 +87,7 @@ runApp env (HGEOptions rci metadataDbUrl hgeCmd) = do
             GC.ourIdleGC logger (seconds 0.3) (seconds 10) (seconds 60)
 
         flip runPGMetadataStorageAppT (scMetadataDbPool, pgLogger) . lowerManagedT $ do
-          runHGEServer (const $ pure ()) env serveOptions serverCtx initTime Nothing ekgStore FeatureFlag.defaultValueIO
+          runHGEServer (const $ pure ()) env serveOptions serverCtx initTime Nothing ekgStore (FeatureFlag.checkFeatureFlag env)
     HCExport -> do
       GlobalCtx {..} <- initGlobalCtx env metadataDbUrl rci
       res <- runTxWithMinimalPool _gcMetadataDbConnInfo fetchMetadataFromCatalog

server/src-lib/Hasura/App.hs

@@ -120,7 +120,7 @@ import Hasura.Server.API.Query (requiresAdmin)
 import Hasura.Server.App
 import Hasura.Server.Auth
 import Hasura.Server.CheckUpdates (checkForUpdates)
-import Hasura.Server.Init
+import Hasura.Server.Init hiding (checkFeatureFlag)
 import Hasura.Server.Limits
 import Hasura.Server.Logging
 import Hasura.Server.Metrics (ServerMetrics (..))

server/src-lib/Hasura/Server/App.hs

@@ -82,7 +82,7 @@ import Hasura.Server.API.V2Query qualified as V2Q
 import Hasura.Server.Auth (AuthMode (..), UserAuthentication (..))
 import Hasura.Server.Compression
 import Hasura.Server.Cors
-import Hasura.Server.Init
+import Hasura.Server.Init hiding (checkFeatureFlag)
 import Hasura.Server.Limits
 import Hasura.Server.Logging
 import Hasura.Server.Metrics (ServerMetrics)

server/src-lib/Hasura/Server/Init/FeatureFlag.hs

@@ -3,7 +3,7 @@
 -- | Feature Flags are /temporary/ toggles.
 module Hasura.Server.Init.FeatureFlag
   ( FeatureFlag (..),
-    defaultValueIO,
+    checkFeatureFlag,
     Identifier (..),
     FeatureFlags (..),
     featureFlags,
@@ -14,6 +14,7 @@ where
 --------------------------------------------------------------------------------
 
 import Data.Aeson (FromJSON, ToJSON)
+import Data.Environment qualified as Env
 import Data.HashMap.Strict qualified as HashMap
 import Hasura.Prelude
 
@@ -27,14 +28,19 @@ newtype Identifier = Identifier {getIdentifier :: Text}
 data FeatureFlag = FeatureFlag
   { ffIdentifier :: Identifier,
     ffDefaultValue :: Bool,
-    ffDescription :: Text
+    ffDescription :: Text,
+    ffEnvVar :: String
   }
   deriving stock (Eq, Generic)
   deriving anyclass (Hashable, FromJSON, ToJSON)
 
--- | We hardcode all feature flags to their default value in OSS.
-defaultValueIO :: FeatureFlag -> IO Bool
-defaultValueIO = pure . ffDefaultValue
+-- | In OSS we look for a environment variable or fall back to the default
+-- value
+checkFeatureFlag :: Env.Environment -> FeatureFlag -> IO Bool
+checkFeatureFlag env (FeatureFlag {ffEnvVar = envVar, ffDefaultValue = defaultValue}) =
+  case Env.lookupEnv env envVar of
+    Just found -> pure $ fromMaybe defaultValue (readMaybe found)
+    Nothing -> pure $ defaultValue
 
 --------------------------------------------------------------------------------
 
@@ -55,7 +61,8 @@ testFlag =
   FeatureFlag
     { ffIdentifier = Identifier "test-flag",
       ffDefaultValue = False,
-      ffDescription = "Testing feature flag integration"
+      ffDescription = "Testing feature flag integration",
+      ffEnvVar = "HASURA_FF_TEST_FLAG"
     }
 
 nativeQueryInterface :: FeatureFlag
@@ -63,5 +70,6 @@ nativeQueryInterface =
   FeatureFlag
     { ffIdentifier = Identifier "native-query-interface",
       ffDefaultValue = False,
-      ffDescription = "Expose custom views, permissions and advanced SQL functionality via custom queries"
+      ffDescription = "Expose custom views, permissions and advanced SQL functionality via custom queries",
+      ffEnvVar = "HASURA_FF_NATIVE_QUERY_INTERFACE"
     }

server/test-postgres/Main.hs

@@ -89,7 +89,7 @@ main = do
                 readOnlyMode
                 Nothing -- We are not testing the naming convention here, so defaulting to hasura-default
                 emptyMetadataDefaults
-                FF.defaultValueIO
+                (FF.checkFeatureFlag mempty)
             cacheBuildParams = CacheBuildParams httpManager (mkPgSourceResolver print) mkMSSQLSourceResolver serverConfigCtx
             pgLogger = print