graphql-engine/server/src-lib/Hasura/GraphQL/Schema/Postgres.hs

Ignoring revisions in .git-blame-ignore-revs. Click here to bypass and see the normal blame view.

66 lines
2.5 KiB
Haskell
Raw Normal View History

-- | Postgres-specific schema combinators. Those should be moved to
-- the corresponding instance of `BackendSchema`, when actions are
-- generalized.
module Hasura.GraphQL.Schema.Postgres
( buildActionQueryFields,
buildActionSubscriptionFields,
buildActionMutationFields,
)
where
import Hasura.GraphQL.Schema.Action
import Hasura.GraphQL.Schema.Common
import Hasura.GraphQL.Schema.Parser
import Hasura.Prelude
server: support remote relationships on SQL Server and BigQuery (#1497) Remote relationships are now supported on SQL Server and BigQuery. The major change though is the re-architecture of remote join execution logic. Prior to this PR, each backend is responsible for processing the remote relationships that are part of their AST. This is not ideal as there is nothing specific about a remote join's execution that ties it to a backend. The only backend specific part is whether or not the specification of the remote relationship is valid (i.e, we'll need to validate whether the scalars are compatible). The approach now changes to this: 1. Before delegating the AST to the backend, we traverse the AST, collect all the remote joins while modifying the AST to add necessary join fields where needed. 1. Once the remote joins are collected from the AST, the database call is made to fetch the response. The necessary data for the remote join(s) is collected from the database's response and one or more remote schema calls are constructed as necessary. 1. The remote schema calls are then executed and the data from the database and from the remote schemas is joined to produce the final response. ### Known issues 1. Ideally the traversal of the IR to collect remote joins should return an AST which does not include remote join fields. This operation can be type safe but isn't taken up as part of the PR. 1. There is a lot of code duplication between `Transport/HTTP.hs` and `Transport/Websocket.hs` which needs to be fixed ASAP. This too hasn't been taken up by this PR. 1. The type which represents the execution plan is only modified to handle our current remote joins and as such it will have to be changed to accommodate general remote joins. 1. Use of lenses would have reduced the boilerplate code to collect remote joins from the base AST. 1. The current remote join logic assumes that the join columns of a remote relationship appear with their names in the database response. This however is incorrect as they could be aliased. This can be taken up by anyone, I've left a comment in the code. ### Notes to the reviewers I think it is best reviewed commit by commit. 1. The first one is very straight forward. 1. The second one refactors the remote join execution logic but other than moving things around, it doesn't change the user facing functionality. This moves Postgres specific parts to `Backends/Postgres` module from `Execute`. Some IR related code to `Hasura.RQL.IR` module. Simplifies various type class function signatures as a backend doesn't have to handle remote joins anymore 1. The third one fixes partial case matches that for some weird reason weren't shown as warnings before this refactor 1. The fourth one generalizes the validation logic of remote relationships and implements `scalarTypeGraphQLName` function on SQL Server and BigQuery which is used by the validation logic. This enables remote relationships on BigQuery and SQL Server. https://github.com/hasura/graphql-engine-mono/pull/1497 GitOrigin-RevId: 77dd8eed326602b16e9a8496f52f46d22b795598
2021-06-11 06:26:50 +03:00
import Hasura.RQL.IR
import Hasura.RQL.Types.Action
import Hasura.RQL.Types.CustomTypes
import Hasura.RQL.Types.Metadata.Object
buildActionQueryFields ::
MonadBuildActionSchema r m n =>
AnnotatedCustomTypes ->
ActionInfo ->
SchemaT r m [FieldParser n (QueryRootField UnpreparedValue)]
buildActionQueryFields customTypes actionInfo =
maybeToList . applyActionOrigin actionInfo
<$> case _adType (_aiDefinition actionInfo) of
ActionQuery ->
fmap (fmap (RFAction . AQQuery)) <$> actionExecute customTypes actionInfo
ActionMutation ActionSynchronous -> pure Nothing
ActionMutation ActionAsynchronous ->
fmap (fmap (RFAction . AQAsync)) <$> actionAsyncQuery (_actObjectTypes customTypes) actionInfo
buildActionMutationFields ::
MonadBuildActionSchema r m n =>
AnnotatedCustomTypes ->
ActionInfo ->
SchemaT r m [FieldParser n (MutationRootField UnpreparedValue)]
buildActionMutationFields customTypes actionInfo =
maybeToList . applyActionOrigin actionInfo
<$> case _adType (_aiDefinition actionInfo) of
ActionQuery -> pure Nothing
ActionMutation ActionSynchronous ->
fmap (fmap (RFAction . AMSync)) <$> actionExecute customTypes actionInfo
ActionMutation ActionAsynchronous ->
fmap (fmap (RFAction . AMAsync)) <$> actionAsyncMutation (_actInputTypes customTypes) actionInfo
buildActionSubscriptionFields ::
MonadBuildActionSchema r m n =>
AnnotatedCustomTypes ->
ActionInfo ->
SchemaT r m [FieldParser n (QueryRootField UnpreparedValue)]
buildActionSubscriptionFields customTypes actionInfo =
maybeToList . applyActionOrigin actionInfo
<$> case _adType (_aiDefinition actionInfo) of
ActionQuery -> pure Nothing
ActionMutation ActionSynchronous -> pure Nothing
ActionMutation ActionAsynchronous ->
fmap (fmap (RFAction . AQAsync)) <$> actionAsyncQuery (_actObjectTypes customTypes) actionInfo
applyActionOrigin ::
ActionInfo ->
Maybe (FieldParser n a) ->
Maybe (FieldParser n a)
applyActionOrigin actionInfo = fmap (setFieldParserOrigin (MOAction (_aiName actionInfo)))