graphql-engine/server/src-lib/Hasura/Backends/BigQuery/DDL/RunSQL.hs

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{-# LANGUAGE TemplateHaskell #-}
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
-- |
-- Working example:
--
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
-- \$ curl -XPOST http://localhost:8080/v2/query -d @- <<EOF
-- {
-- "type":"bigquery_run_sql",
-- "args": {
-- "sql":"select 3 * 4 as foo, \"Hello, World!\" as bar",
-- "source":"chinook"
-- }
-- }
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
-- EOF
-- {"result_type":"TuplesOk","result":[["foo","bar"],["12","Hello, World!"]]}
module Hasura.Backends.BigQuery.DDL.RunSQL
( runSQL,
runDatabaseInspection,
BigQueryRunSQL,
)
where
import Data.Aeson qualified as J
import Data.Aeson.TH (deriveJSON)
import Data.Aeson.Text (encodeToLazyText)
import Data.HashMap.Strict.InsOrd qualified as OMap
import Data.Text qualified as T
import Data.Text.Lazy qualified as LT
import Data.Vector qualified as V
import Hasura.Backends.BigQuery.Execute qualified as Execute
import Hasura.Backends.BigQuery.Source (BigQueryDataset (..), BigQuerySourceConfig (..))
import Hasura.Base.Error
import Hasura.EncJSON
import Hasura.Prelude
import Hasura.RQL.DDL.Schema (RunSQLRes (..))
import Hasura.RQL.Types.Common
import Hasura.RQL.Types.Metadata
import Hasura.RQL.Types.SchemaCache
import Hasura.RQL.Types.SchemaCache.Build
import Hasura.SQL.Backend
data BigQueryRunSQL = BigQueryRunSQL
{ _mrsSql :: Text,
_mrsSource :: SourceName
}
deriving (Show, Eq)
$(deriveJSON hasuraJSON ''BigQueryRunSQL)
runSQL ::
(MonadIO m, CacheRWM m, MonadError QErr m, MetadataM m) =>
BigQueryRunSQL ->
m EncJSON
runSQL = runSQL_ recordSetAsHeaderAndRows
-- | The SQL query in the request is ignored
runDatabaseInspection ::
(MonadIO m, CacheRWM m, MonadError QErr m, MetadataM m) =>
BigQueryRunSQL ->
m EncJSON
runDatabaseInspection (BigQueryRunSQL _query source) = do
BigQuerySourceConfig {_scDatasets = dataSets} <- askSourceConfig @'BigQuery source
let queries =
[ "SELECT *, ARRAY(SELECT as STRUCT * from "
<> getBigQueryDataset dataSet
<> ".INFORMATION_SCHEMA.COLUMNS WHERE table_name = t.table_name) as columns from "
<> getBigQueryDataset dataSet
<> ".INFORMATION_SCHEMA.TABLES as t"
| dataSet <- dataSets
]
query' = T.intercalate " UNION ALL " queries
runSQL_ recordSetAsSchema (BigQueryRunSQL query' source)
runSQL_ ::
(MonadIO m, CacheRWM m, MonadError QErr m, MetadataM m) =>
(Execute.RecordSet -> J.Value) ->
BigQueryRunSQL ->
m EncJSON
runSQL_ f (BigQueryRunSQL query source) = do
sourceConfig <- askSourceConfig @'BigQuery source
result <-
Execute.streamBigQuery
(_scConnection sourceConfig)
Execute.BigQuery {query = LT.fromStrict query, parameters = mempty}
case result of
Left executeProblem -> do
let errorMessage = Execute.executeProblemMessage Execute.HideDetails executeProblem
throwError (err400 BigQueryError errorMessage) {qeInternal = Just $ ExtraInternal $ J.toJSON executeProblem}
Right recordSet ->
pure
( encJFromJValue
(RunSQLRes "TuplesOk" (f recordSet))
)
recordSetAsHeaderAndRows :: Execute.RecordSet -> J.Value
recordSetAsHeaderAndRows Execute.RecordSet {rows} = J.toJSON (thead : tbody)
where
thead =
case rows V.!? 0 of
Nothing -> []
Just row ->
map (J.toJSON . (coerce :: Execute.FieldNameText -> Text)) (OMap.keys row)
tbody :: [[J.Value]]
tbody = map (map J.toJSON . OMap.elems) (toList rows)
recordSetAsSchema :: Execute.RecordSet -> J.Value
recordSetAsSchema rs@(Execute.RecordSet {rows}) =
recordSetAsHeaderAndRows $
rs
{ Execute.rows =
OMap.adjust
(Execute.TextOutputValue . LT.toStrict . encodeToLazyText . J.toJSON)
(Execute.FieldNameText "columns")
<$> rows
}