mirror of
https://github.com/hasura/graphql-engine.git
synced 2024-12-15 01:12:56 +03:00
server: query remote server in a remote join query iff all arguments are not null (#31)
* server: query remote server in a remote join query iff all arguments are not null Co-authored-by: Karthikeyan Chinnakonda <karthikeyan@hasura.io> GITHUB_PR_NUMBER: 6199 GITHUB_PR_URL: https://github.com/hasura/graphql-engine/pull/6199 * Update server/src-lib/Hasura/Backends/Postgres/Execute/RemoteJoin.hs Co-authored-by: Brandon Simmons <brandon@hasura.io> * Apply suggestions from code review Co-authored-by: Brandon Simmons <brandon@hasura.io> * Update server/tests-py/test_remote_relationships.py Co-authored-by: Brandon Simmons <brandon@hasura.io> * Apply suggestions from code review Co-authored-by: Brandon Simmons <brandon@hasura.io> * use guard instead of case match * add comment about the remote relationship joining * add a comment about the design discussion * update CHANGELOG Co-authored-by: Karthikeyan Chinnakonda <karthikeyan@hasura.io> Co-authored-by: Brandon Simmons <brandon@hasura.io> GitOrigin-RevId: ce7e8288d37ad7c32705f96cb6363f6ad68f3c0a
This commit is contained in:
hasura-bot
parent
320835a6f2
commit
8eebcb9bdf
20
CHANGELOG.md
20
CHANGELOG.md
@ -123,6 +123,26 @@ const newTable: TableEntry = {
|
||||
|
||||
|
||||
|
||||
### Breaking changes
|
||||
|
||||
#### PDV
|
||||
|
||||
This release contains the [PDV refactor (#4111)](https://github.com/hasura/graphql-engine/pull/4111), a significant rewrite of the internals of the server, which did include some breaking changes:
|
||||
|
||||
- The semantics of explicit `null` values in `where` filters have changed according to the discussion in [issue 704](https://github.com/hasura/graphql-engine/issues/704#issuecomment-635571407): an explicit `null` value in a comparison input object will be treated as an error rather than resulting in the expression being evaluated to `True`. For instance: `delete_users(where: {id: {_eq: $userId}}) { name }` will yield an error if `$userId` is `null` instead of deleting all users.
|
||||
- The validation of required headers has been fixed (closing #14 and #3659):
|
||||
- if a query selects table `bar` through table `foo` via a relationship, the required permissions headers will be the union of the required headers of table `foo` and table `bar` (we used to only check the headers of the root table);
|
||||
- if an insert does not have an `on_conflict` clause, it will not require the update permissions headers.
|
||||
|
||||
#### Remote Relationship
|
||||
|
||||
In this release, a breaking change has been introduced:
|
||||
|
||||
In a remote relationship query, the remote schema will be queried when all of the joining arguments
|
||||
are **not** `null` values. When there are `null` value(s), the remote schema won't be queried and the
|
||||
response of the remote relationship field will be `null`. Earlier, the remote schema
|
||||
was queried with the `null` value arguments and the response depended upon how the remote schema handled the `null`
|
||||
arguments.
|
||||
|
||||
### Bug fixes and improvements
|
||||
|
||||
|
||||
@ -49,7 +49,6 @@ import Hasura.RQL.Types
|
||||
import Hasura.Server.Version (HasVersion)
|
||||
import Hasura.Session
|
||||
|
||||
|
||||
-- | Executes given query and fetch response JSON from Postgres. Substitutes remote relationship fields.
|
||||
executeQueryWithRemoteJoins
|
||||
:: ( HasVersion
|
||||
@ -89,7 +88,8 @@ processRemoteJoins env manager reqHdrs userInfo pgRes rjs = do
|
||||
jsonRes <- onLeft (AO.eitherDecode pgRes) (throw500 . T.pack)
|
||||
-- Step 2: Traverse through the JSON obtained in above step and generate composite JSON value with remote joins
|
||||
compositeJson <- traverseQueryResponseJSON rjMap jsonRes
|
||||
let remoteJoins = collectRemoteFields compositeJson
|
||||
-- The remote server is queried only when all of the joining fields are *not* NULL:
|
||||
let remoteJoins = catMaybes $ collectRemoteFields compositeJson
|
||||
-- Step 3: Make queries to remote server and fetch graphql response
|
||||
remoteServerResp <- fetchRemoteJoinFields env manager reqHdrs userInfo remoteJoins
|
||||
-- Step 4: Replace remote fields in composite json with remote join values
|
||||
@ -313,7 +313,7 @@ data RemoteJoinField
|
||||
-- from remote join map and query response JSON from Postgres.
|
||||
traverseQueryResponseJSON
|
||||
:: (MonadError QErr m)
|
||||
=> RemoteJoinMap 'Postgres -> AO.Value -> m (CompositeValue RemoteJoinField)
|
||||
=> RemoteJoinMap 'Postgres -> AO.Value -> m (CompositeValue (Maybe RemoteJoinField))
|
||||
traverseQueryResponseJSON rjm =
|
||||
flip runReaderT rjm . flip evalStateT (Counter 0) . traverseValue mempty
|
||||
where
|
||||
@ -322,24 +322,72 @@ traverseQueryResponseJSON rjm =
|
||||
askRemoteJoins path = asks (Map.lookup path)
|
||||
|
||||
traverseValue :: (MonadError QErr m, MonadReader (RemoteJoinMap 'Postgres) m, MonadState Counter m)
|
||||
=> FieldPath -> AO.Value -> m (CompositeValue RemoteJoinField)
|
||||
=> FieldPath -> AO.Value -> m (CompositeValue (Maybe RemoteJoinField))
|
||||
traverseValue path = \case
|
||||
AO.Object obj -> traverseObject obj
|
||||
AO.Array arr -> CVObjectArray <$> mapM (traverseValue path) (toList arr)
|
||||
v -> pure $ CVOrdValue v
|
||||
|
||||
where
|
||||
mkRemoteSchemaField siblingFields remoteJoin = do
|
||||
mkRemoteSchemaField
|
||||
:: (MonadError QErr m, MonadState Counter m)
|
||||
=> AO.Object
|
||||
-> RemoteJoin 'Postgres
|
||||
-> m (Maybe RemoteJoinField)
|
||||
mkRemoteSchemaField siblingFields remoteJoin = runMaybeT $ do
|
||||
counter <- getCounter
|
||||
let RemoteJoin fieldName inputArgs selSet hasuraFields fieldCall rsi _ = remoteJoin
|
||||
hasuraFieldVariables <- mapM (parseGraphQLName . getFieldNameTxt) $ toList hasuraFields
|
||||
siblingFieldArgsVars <- mapM (\(k,val) -> do
|
||||
-- when any of the joining fields are `NULL`, we don't query
|
||||
-- the remote schema
|
||||
--
|
||||
-- The rationale for performing such a join is that, postgres
|
||||
-- implements joins in the same way. For example:
|
||||
-- Let's say we have the following tables
|
||||
--
|
||||
-- test_db=# select * from users;
|
||||
-- id | first_name | last_name
|
||||
-- ----+------------+-----------
|
||||
-- 4 | foo |
|
||||
-- 5 | baz | bar
|
||||
-- 6 | hello |
|
||||
-- (3 rows)
|
||||
|
||||
-- test_db=# select * from address;
|
||||
-- id | first_name | last_name | address
|
||||
-- ----+------------+-----------+----------
|
||||
-- 4 | foo | | address1
|
||||
-- 5 | baz | bar | address2
|
||||
-- 6 | | hello | address3
|
||||
--
|
||||
-- Executing the following query:
|
||||
-- select u.first_name,u.last_name,a.address
|
||||
-- from users u
|
||||
-- left join address a on u.first_name = a.first_name
|
||||
-- and u.last_name = a.last_name;
|
||||
--
|
||||
-- gives the following result:
|
||||
--
|
||||
-- first_name | last_name | address
|
||||
-- -----------+-----------+----------
|
||||
-- baz | bar | address2
|
||||
-- foo | |
|
||||
-- hello | |
|
||||
--
|
||||
-- The data from the `address` table is fetched only when all
|
||||
-- of the arguments are **NOT** NULL.
|
||||
--
|
||||
-- For discussion of this design here
|
||||
-- see: https://github.com/hasura/graphql-engine-mono/pull/31#issuecomment-728230307
|
||||
for_ hasuraFields $ \(FieldName fieldNameTxt) -> do
|
||||
fldValue <- hoistMaybe $ AO.lookup fieldNameTxt siblingFields
|
||||
guard $ fldValue /= AO.Null
|
||||
hasuraFieldVariables <- lift $ mapM (parseGraphQLName . getFieldNameTxt) $ toList hasuraFields
|
||||
siblingFieldArgsVars <- lift $ mapM (\(k,val) -> do
|
||||
(,) <$> parseGraphQLName k <*> ordJSONValueToGValue val)
|
||||
$ siblingFields
|
||||
$ AO.toList siblingFields
|
||||
let siblingFieldArgs = Map.fromList $ siblingFieldArgsVars
|
||||
hasuraFieldArgs = flip Map.filterWithKey siblingFieldArgs $ \k _ -> k `elem` hasuraFieldVariables
|
||||
fieldAlias <- pathToAlias (appendPath fieldName path) counter
|
||||
queryField <- fieldCallsToField (inputArgsToMap inputArgs) hasuraFieldArgs selSet fieldAlias fieldCall
|
||||
fieldAlias <- lift $ pathToAlias (appendPath fieldName path) counter
|
||||
queryField <- lift $ fieldCallsToField (inputArgsToMap inputArgs) hasuraFieldArgs selSet fieldAlias fieldCall
|
||||
pure $ RemoteJoinField rsi
|
||||
fieldAlias
|
||||
queryField
|
||||
@ -364,9 +412,9 @@ traverseQueryResponseJSON rjm =
|
||||
phantomColumnFields = map (fromPGCol . pgiColumn) $
|
||||
concatMap _rjPhantomFields remoteJoins
|
||||
if | fieldName `elem` phantomColumnFields -> pure Nothing
|
||||
| otherwise ->
|
||||
| otherwise -> do
|
||||
case find ((== fieldName) . _rjName) remoteJoins of
|
||||
Just rj -> Just . CVFromRemote <$> mkRemoteSchemaField fields rj
|
||||
Just rj -> Just . CVFromRemote <$> mkRemoteSchemaField obj rj
|
||||
Nothing -> Just <$> traverseValue fieldPath value
|
||||
pure $ CVObject $ OMap.fromList processedFields
|
||||
|
||||
@ -499,16 +547,18 @@ fetchRemoteJoinFields env manager reqHdrs userInfo remoteJoins = do
|
||||
-- | Replace 'RemoteJoinField' in composite JSON with it's json value from remote server response.
|
||||
replaceRemoteFields
|
||||
:: MonadError QErr m
|
||||
=> CompositeValue RemoteJoinField
|
||||
=> CompositeValue (Maybe RemoteJoinField)
|
||||
-> AO.Object
|
||||
-> m AO.Value
|
||||
replaceRemoteFields compositeJson remoteServerResponse =
|
||||
compositeValueToJSON <$> traverse replaceValue compositeJson
|
||||
where
|
||||
replaceValue rj = do
|
||||
let alias = _rjfAlias rj
|
||||
fieldCall = _rjfFieldCall rj
|
||||
extractAtPath (alias:fieldCall) $ AO.Object remoteServerResponse
|
||||
-- `Nothing` below signifies that at-least one of the joining fields was NULL
|
||||
-- , when that happens we have to manually insert the `NULL` value for the
|
||||
-- remoteField value in the response.
|
||||
replaceValue Nothing = pure $ AO.Null
|
||||
replaceValue (Just RemoteJoinField {_rjfAlias, _rjfFieldCall}) =
|
||||
extractAtPath (_rjfAlias:_rjfFieldCall) $ AO.Object remoteServerResponse
|
||||
|
||||
-- | 'FieldCall' is path to remote relationship value in remote server response.
|
||||
-- 'extractAtPath' traverse through the path and extracts the json value
|
||||
@ -606,9 +656,8 @@ substituteVariables values = traverse go
|
||||
where
|
||||
go = \case
|
||||
G.VVariable variableName ->
|
||||
case Map.lookup variableName values of
|
||||
Nothing -> Failure ["Value for variable " <> variableName <<> " not provided"]
|
||||
Just value -> pure value
|
||||
onNothing (Map.lookup variableName values) $
|
||||
Failure ["Value for variable " <> variableName <<> " not provided"]
|
||||
G.VList listValue ->
|
||||
fmap G.VList (traverse go listValue)
|
||||
G.VObject objectValue ->
|
||||
|
||||
@ -15,6 +15,7 @@ module Hasura.Prelude
|
||||
, base64Decode
|
||||
, spanMaybeM
|
||||
, liftEitherM
|
||||
, hoistMaybe
|
||||
-- * Efficient coercions
|
||||
, coerce
|
||||
, findWithIndex
|
||||
@ -179,3 +180,7 @@ startTimer = do
|
||||
return $ do
|
||||
aft <- liftIO Clock.getMonotonicTimeNSec
|
||||
return $ nanoseconds $ fromIntegral (aft - bef)
|
||||
|
||||
-- copied from http://hackage.haskell.org/package/errors-2.3.0/docs/src/Control.Error.Util.html#hoistMaybe
|
||||
hoistMaybe :: (Monad m) => Maybe b -> MaybeT m b
|
||||
hoistMaybe = MaybeT . return
|
||||
|
||||
@ -0,0 +1,33 @@
|
||||
description: Remote join with null joining fields
|
||||
url: /v1/graphql
|
||||
status: 200
|
||||
response:
|
||||
data:
|
||||
employees:
|
||||
- id: 1
|
||||
name: alice
|
||||
employeeMessages:
|
||||
- id: 1
|
||||
name: alice
|
||||
msg: You win!
|
||||
- id: 2
|
||||
name: null
|
||||
# since the join argument (name) was `NULL`, we don't perform the remote query
|
||||
# and just return `null` for the joined field:
|
||||
employeeMessages: null
|
||||
- id: 3
|
||||
name: bob
|
||||
employeeMessages: []
|
||||
query:
|
||||
query: |
|
||||
query {
|
||||
employees {
|
||||
id
|
||||
name
|
||||
employeeMessages {
|
||||
id
|
||||
name
|
||||
msg
|
||||
}
|
||||
}
|
||||
}
|
||||
@ -52,3 +52,17 @@ args:
|
||||
args:
|
||||
schema: public
|
||||
name: authors
|
||||
|
||||
- type: run_sql
|
||||
args:
|
||||
sql: |
|
||||
create table employees (
|
||||
id serial primary key,
|
||||
name text
|
||||
);
|
||||
insert into employees (name) values ('alice'),(NULL),('bob');
|
||||
|
||||
- type: track_table
|
||||
args:
|
||||
schema: public
|
||||
name: employees
|
||||
|
||||
@ -0,0 +1,16 @@
|
||||
type: create_remote_relationship
|
||||
args:
|
||||
name: employeeMessages
|
||||
table: employees
|
||||
hasura_fields:
|
||||
- id
|
||||
- name
|
||||
remote_schema: my-remote-schema
|
||||
remote_field:
|
||||
messages:
|
||||
arguments:
|
||||
where:
|
||||
name:
|
||||
eq: "$name"
|
||||
includes:
|
||||
id: ["$id"]
|
||||
@ -15,6 +15,11 @@ args:
|
||||
sql: |
|
||||
drop table if exists authors
|
||||
|
||||
- type: run_sql
|
||||
args:
|
||||
sql: |
|
||||
drop table if exists employees
|
||||
|
||||
# also drops remote relationship as direct dep
|
||||
- type: remove_remote_schema
|
||||
args:
|
||||
|
||||
@ -186,6 +186,12 @@ class TestExecution:
|
||||
assert st_code == 200, resp
|
||||
check_query_f(hge_ctx, self.dir() + 'basic_multiple_fields.yaml')
|
||||
|
||||
# https://github.com/hasura/graphql-engine/issues/5448
|
||||
def test_remote_join_fields_with_null_joining_fields(self, hge_ctx):
|
||||
st_code, resp = hge_ctx.v1q_f(self.dir() + 'setup_remote_rel_null_joining_fields.yaml')
|
||||
assert st_code == 200, resp
|
||||
check_query_f(hge_ctx, self.dir() + 'remote_rel_with_null_joining_fields.yaml')
|
||||
|
||||
def test_nested_fields(self, hge_ctx):
|
||||
st_code, resp = hge_ctx.v1q_f(self.dir() + 'setup_remote_rel_nested_fields.yaml')
|
||||
assert st_code == 200, resp
|
||||
|
||||
Loading…
Reference in New Issue
Block a user