server: fine tune cron triggers behaviour in replace metadata API call

https://github.com/hasura/graphql-engine-mono/pull/1991

GitOrigin-RevId: 7eb7d7b20d0a03eda7829d3a17a35dffe0f7bf1a

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## Next release
 (Add entries below in the order of server, console, cli, docs, others)
 
+- server: preserve unchanged cron triggers in `replace_metadata` API
 - server: fix inherited roles bug where mutations were not accessible when inherited roles was enabled
 - server: reintroduce the unique name constraint in allowed lists
 - server: fix http-log bug where batches with only one request emitted the parameterised query hash as a string instead of in a singleton array

server/src-lib/Data/HashMap/Strict/InsOrd/Extended.hs

@@ -2,15 +2,16 @@ module Data.HashMap.Strict.InsOrd.Extended
   ( module OMap
   , groupTuples
   , groupListWith
+  , partition
   ) where
 
 import           Data.HashMap.Strict.InsOrd as OMap
-import qualified Data.Sequence.NonEmpty     as NE
 import qualified Data.List                  as L
+import qualified Data.Sequence.NonEmpty     as NE
 
 import           Data.Hashable              (Hashable)
 
-import           Prelude                    (Eq, Foldable, Functor, flip, fmap, ($), (<>))
+import           Prelude
 
 groupTuples
   :: (Eq k, Hashable k, Foldable t)
@@ -26,3 +27,12 @@ groupListWith
   => (v -> k) -> t v -> OMap.InsOrdHashMap k (NE.NESeq v)
 groupListWith f l =
   groupTuples $ fmap (\v -> (f v, v)) l
+
+partition :: (Eq k, Hashable k) => (v -> Bool) -> OMap.InsOrdHashMap k v -> (OMap.InsOrdHashMap k v, OMap.InsOrdHashMap k v)
+partition predicate =
+  OMap.foldlWithKey'
+    (\(left, right) key val ->
+       if (predicate val)
+       then (OMap.insert key val left, right)
+       else (left, OMap.insert key val right))
+    (mempty, mempty)

server/src-lib/Hasura/RQL/DDL/Metadata.hs

@@ -20,7 +20,8 @@ module Hasura.RQL.DDL.Metadata
 import           Hasura.Prelude
 
 import qualified Data.Aeson.Ordered                  as AO
-import qualified Data.HashMap.Strict.InsOrd         as OMap
+import qualified Data.HashMap.Strict                 as Map
+import qualified Data.HashMap.Strict.InsOrd.Extended as OMap
 import qualified Data.HashSet                        as HS
 import qualified Data.List                           as L
 
@@ -149,28 +150,11 @@ runReplaceMetadataV2 ReplaceMetadataV2{..} = do
           RMWithoutSources _ -> emptyQueryTagsConfig
 
   oldMetadata <- getMetadata
-  let (oldCronTriggersIncludedInMetadata, oldCronTriggersNotIncludedInMetadata) =
-        (OMap.filter ctIncludeInMetadata (_metaCronTriggers  oldMetadata)
-        ,OMap.filter (not . ctIncludeInMetadata) (_metaCronTriggers  oldMetadata))
-      newCronTriggers =
-        case _rmv2Metadata of
-          RMWithoutSources m -> _mnsCronTriggers m
-          RMWithSources m    -> _metaCronTriggers m
-  dropFutureCronEvents $ MetadataCronTriggers $ OMap.keys oldCronTriggersIncludedInMetadata
-  cronTriggers <- do
-    -- traverse over the new cron triggers and check if any of them
-    -- already exists as a cron trigger with "included_in_metadata: false"
-    for_ newCronTriggers $ \ct ->
-      when (ctName ct `OMap.member` oldCronTriggersNotIncludedInMetadata) $
-        throw400 AlreadyExists $
-        "cron trigger with name "
-        <> ctName ct
-        <<> " already exists as a cron trigger with \"included_in_metadata\" as false"
-    -- we add the old cron triggers with included_in_metadata set to false with the
-    -- newly added cron triggers
-    pure $ newCronTriggers <> oldCronTriggersNotIncludedInMetadata
+
+  (cronTriggersMetadata, cronTriggersToBeAdded) <- processCronTriggers oldMetadata
+
   metadata <- case _rmv2Metadata of
-    RMWithSources m -> pure $ m { _metaCronTriggers = cronTriggers }
+    RMWithSources m -> pure $ m { _metaCronTriggers = cronTriggersMetadata }
     RMWithoutSources MetadataNoSources{..} -> do
       let maybeDefaultSourceMetadata = oldMetadata ^? metaSources.ix defaultSource.toSourceMetadata
       defaultSourceMetadata <- onNothing maybeDefaultSourceMetadata $
@@ -181,7 +165,7 @@ runReplaceMetadataV2 ReplaceMetadataV2{..} = do
                                      }
       pure $ Metadata (OMap.singleton defaultSource newDefaultSourceMetadata)
                         _mnsRemoteSchemas _mnsQueryCollections _mnsAllowlist
-                        _mnsCustomTypes _mnsActions cronTriggers (_metaRestEndpoints oldMetadata)
+                        _mnsCustomTypes _mnsActions cronTriggersMetadata (_metaRestEndpoints oldMetadata)
                         emptyApiLimit emptyMetricsConfig mempty introspectionDisabledRoles queryTagsConfig
   putMetadata metadata
 
@@ -192,7 +176,7 @@ runReplaceMetadataV2 ReplaceMetadataV2{..} = do
       buildSchemaCacheStrict
 
   -- populate future cron events for all the new cron triggers that are imported
-  for_ newCronTriggers $ \CronTriggerMetadata {..} ->
+  for_ cronTriggersToBeAdded $ \CronTriggerMetadata {..} ->
     populateInitialCronTriggerEvents ctSchedule ctName
 
   -- See Note [Clear postgres schema for dropped triggers]
@@ -203,6 +187,62 @@ runReplaceMetadataV2 ReplaceMetadataV2{..} = do
     getOnlyPGSources :: Metadata -> InsOrdHashMap SourceName (SourceMetadata ('Postgres 'Vanilla))
     getOnlyPGSources = OMap.mapMaybe AB.unpackAnyBackend . _metaSources
 
+    {- Note [Cron triggers behaviour with replace metadata]
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+    When the metadata is replaced, we delete only the cron triggers
+    that were deleted, instead of deleting all the old cron triggers (which
+    existed in the metadata before it was replaced) and inserting all the
+    new cron triggers. This is done this way, because when a cron trigger is
+    dropped, the cron events associated with it will also be dropped from the DB
+    and when a new cron trigger is added, new cron events are generated by the
+    graphql-engine. So, this way we only delete and insert the data which has been changed.
+
+    The cron triggers that were deleted is calculated by getting a diff
+    of the old cron triggers and the new cron triggers. Note that we don't just
+    check the name of the trigger to calculate the diff, the whole cron trigger
+    definition is considered in the calculation.
+
+    Note: Only cron triggers with `include_in_metadata` set to `true` can be updated/deleted
+    via the replace metadata API. Cron triggers with `include_in_metadata` can only be modified
+    via the `create_cron_trigger` and `delete_cron_trigger` APIs.
+
+    -}
+    processCronTriggers oldMetadata = do
+      let (oldCronTriggersIncludedInMetadata, oldCronTriggersNotIncludedInMetadata) =
+            OMap.partition ctIncludeInMetadata (_metaCronTriggers oldMetadata)
+          allNewCronTriggers =
+            case _rmv2Metadata of
+              RMWithoutSources m -> _mnsCronTriggers m
+              RMWithSources m    -> _metaCronTriggers m
+          -- this function is intended to use with `Map.differenceWith`, it's used when two
+          -- equal keys are encountered, then the values are compared to calculate the diff.
+          -- see https://hackage.haskell.org/package/unordered-containers-0.2.14.0/docs/Data-HashMap-Internal.html#v:differenceWith
+          leftIfDifferent l r
+            | l == r    = Nothing
+            | otherwise = Just l
+          cronTriggersToBeAdded = Map.differenceWith leftIfDifferent
+                                                     (OMap.toHashMap allNewCronTriggers)
+                                                     (OMap.toHashMap oldCronTriggersIncludedInMetadata)
+          cronTriggersToBeDropped = Map.differenceWith leftIfDifferent
+                                                       (OMap.toHashMap oldCronTriggersIncludedInMetadata)
+                                                       (OMap.toHashMap allNewCronTriggers)
+      dropFutureCronEvents $ MetadataCronTriggers $ Map.keys cronTriggersToBeDropped
+      cronTriggers <- do
+        -- traverse over the new cron triggers and check if any of them
+        -- already exists as a cron trigger with "included_in_metadata: false"
+        for_ allNewCronTriggers $ \ct ->
+          when (ctName ct `OMap.member` oldCronTriggersNotIncludedInMetadata) $
+            throw400 AlreadyExists $
+            "cron trigger with name "
+            <> ctName ct
+            <<> " already exists as a cron trigger with \"included_in_metadata\" as false"
+        -- we add the old cron triggers with included_in_metadata set to false with the
+        -- newly added cron triggers
+        pure $ allNewCronTriggers <> oldCronTriggersNotIncludedInMetadata
+      pure $ (cronTriggers, cronTriggersToBeAdded)
+
+
     dropPostgresTriggers
       :: InsOrdHashMap SourceName (SourceMetadata ('Postgres 'Vanilla)) -- ^ old pg sources
       -> InsOrdHashMap SourceName (SourceMetadata ('Postgres 'Vanilla)) -- ^ new pg sources