mirror of
https://github.com/hasura/graphql-engine.git
synced 2024-12-17 12:31:52 +03:00
173 lines
6.8 KiB
Haskell
173 lines
6.8 KiB
Haskell
{-| This module (along with the various @Hasura.RQL.DDL.Schema.*@ modules) provides operations to
|
||
load and modify the Hasura catalog and schema cache.
|
||
|
||
* The /catalog/ refers to the set of PostgreSQL tables and views that store all schema information
|
||
known by Hasura. This includes any tracked Postgres tables, views, and functions, all remote
|
||
schemas, and any additionaly Hasura-specific information such as permissions and relationships.
|
||
|
||
Primitive functions for loading and modifying the catalog are defined in
|
||
"Hasura.RQL.DDL.Schema.Catalog", but most uses are wrapped by other functions to synchronize
|
||
catalog information with the information in the schema cache.
|
||
|
||
* The /schema cache/ is a process-global value of type 'SchemaCache' that stores an in-memory
|
||
representation of the data stored in the catalog. The in-memory representation is not identical
|
||
to the data in the catalog, since it has some post-processing applied to it in order to make it
|
||
easier to consume for other parts of the system, such as GraphQL schema generation. For example,
|
||
although column information is represented by 'RawColumnInfo', the schema cache contains
|
||
“processed” 'ColumnInfo' values, instead.
|
||
|
||
Ultimately, the catalog is the source of truth for all information contained in the schema
|
||
cache, but to avoid rebuilding the entire schema cache on every change to the catalog, various
|
||
functions incrementally update the cache when they modify the catalog.
|
||
-}
|
||
|
||
{-# LANGUAGE RecordWildCards #-}
|
||
|
||
module Hasura.RQL.DDL.Schema
|
||
( module Hasura.RQL.DDL.Schema.Cache
|
||
, module Hasura.RQL.DDL.Schema.Catalog
|
||
, module Hasura.RQL.DDL.Schema.Function
|
||
, module Hasura.RQL.DDL.Schema.Rename
|
||
, module Hasura.RQL.DDL.Schema.Table
|
||
|
||
, RunSQL(..)
|
||
, runRunSQL
|
||
, isSchemaCacheBuildRequiredRunSQL
|
||
) where
|
||
|
||
import Hasura.Prelude
|
||
|
||
import qualified Data.Text as T
|
||
import qualified Data.Text.Encoding as TE
|
||
import qualified Database.PG.Query as Q
|
||
import qualified Database.PostgreSQL.LibPQ as PQ
|
||
import qualified Text.Regex.TDFA as TDFA
|
||
|
||
import Data.Aeson
|
||
import Data.Aeson.Casing
|
||
import Data.Aeson.TH
|
||
import Language.Haskell.TH.Syntax (Lift)
|
||
|
||
import Hasura.EncJSON
|
||
import Hasura.RQL.DDL.Schema.Cache
|
||
import Hasura.RQL.DDL.Schema.Catalog
|
||
import Hasura.RQL.DDL.Schema.Function
|
||
import Hasura.RQL.DDL.Schema.Rename
|
||
import Hasura.RQL.DDL.Schema.Table
|
||
import Hasura.RQL.Instances ()
|
||
import Hasura.RQL.Types
|
||
import Hasura.Server.Utils (quoteRegex)
|
||
|
||
data RunSQL
|
||
= RunSQL
|
||
{ rSql :: Text
|
||
, rCascade :: !Bool
|
||
, rCheckMetadataConsistency :: !(Maybe Bool)
|
||
, rTxAccessMode :: !Q.TxAccess
|
||
} deriving (Show, Eq, Lift)
|
||
|
||
instance FromJSON RunSQL where
|
||
parseJSON = withObject "RunSQL" $ \o -> do
|
||
rSql <- o .: "sql"
|
||
rCascade <- o .:? "cascade" .!= False
|
||
rCheckMetadataConsistency <- o .:? "check_metadata_consistency"
|
||
isReadOnly <- o .:? "read_only" .!= False
|
||
let rTxAccessMode = if isReadOnly then Q.ReadOnly else Q.ReadWrite
|
||
pure RunSQL{..}
|
||
|
||
instance ToJSON RunSQL where
|
||
toJSON RunSQL {..} =
|
||
object
|
||
[ "sql" .= rSql
|
||
, "cascade" .= rCascade
|
||
, "check_metadata_consistency" .= rCheckMetadataConsistency
|
||
, "read_only" .=
|
||
case rTxAccessMode of
|
||
Q.ReadOnly -> True
|
||
Q.ReadWrite -> False
|
||
]
|
||
|
||
-- | see Note [Checking metadata consistency in run_sql]
|
||
isSchemaCacheBuildRequiredRunSQL :: RunSQL -> Bool
|
||
isSchemaCacheBuildRequiredRunSQL RunSQL {..} =
|
||
case rTxAccessMode of
|
||
Q.ReadOnly -> False
|
||
Q.ReadWrite -> fromMaybe (containsDDLKeyword rSql) rCheckMetadataConsistency
|
||
where
|
||
containsDDLKeyword :: Text -> Bool
|
||
containsDDLKeyword = TDFA.match $$(quoteRegex
|
||
TDFA.defaultCompOpt
|
||
{ TDFA.caseSensitive = False
|
||
, TDFA.multiline = True
|
||
, TDFA.lastStarGreedy = True }
|
||
TDFA.defaultExecOpt
|
||
{ TDFA.captureGroups = False }
|
||
"\\balter\\b|\\bdrop\\b|\\breplace\\b|\\bcreate function\\b|\\bcomment on\\b")
|
||
|
||
runRunSQL :: (MonadTx m, CacheRWM m, HasSQLGenCtx m) => RunSQL -> m EncJSON
|
||
runRunSQL q@RunSQL {..}
|
||
-- see Note [Checking metadata consistency in run_sql]
|
||
| isSchemaCacheBuildRequiredRunSQL q
|
||
= withMetadataCheck rCascade $ execRawSQL rSql
|
||
| otherwise
|
||
= execRawSQL rSql
|
||
where
|
||
execRawSQL :: (MonadTx m) => Text -> m EncJSON
|
||
execRawSQL =
|
||
fmap (encJFromJValue @RunSQLRes) . liftTx . Q.multiQE rawSqlErrHandler . Q.fromText
|
||
where
|
||
rawSqlErrHandler txe =
|
||
(err400 PostgresError "query execution failed") { qeInternal = Just $ toJSON txe }
|
||
|
||
{- Note [Checking metadata consistency in run_sql]
|
||
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
||
SQL queries executed by run_sql may change the Postgres schema in arbitrary
|
||
ways. We attempt to automatically update the metadata to reflect those changes
|
||
as much as possible---for example, if a table is renamed, we want to update the
|
||
metadata to track the table under its new name instead of its old one. This
|
||
schema diffing (plus some integrity checking) is handled by withMetadataCheck.
|
||
|
||
But this process has overhead---it involves reloading the metadata, diffing it,
|
||
and rebuilding the schema cache---so we don’t want to do it if it isn’t
|
||
necessary. The user can explicitly disable the check via the
|
||
check_metadata_consistency option, and we also skip it if the current
|
||
transaction is in READ ONLY mode, since the schema can’t be modified in that
|
||
case, anyway.
|
||
|
||
However, even if neither read_only or check_metadata_consistency is passed, lots
|
||
of queries may not modify the schema at all. As a (fairly stupid) heuristic, we
|
||
check if the query contains any keywords for DDL operations, and if not, we skip
|
||
the metadata check as well. -}
|
||
|
||
data RunSQLRes
|
||
= RunSQLRes
|
||
{ rrResultType :: !Text
|
||
, rrResult :: !Value
|
||
} deriving (Show, Eq)
|
||
$(deriveJSON (aesonDrop 2 snakeCase) ''RunSQLRes)
|
||
|
||
instance Q.FromRes RunSQLRes where
|
||
fromRes (Q.ResultOkEmpty _) =
|
||
return $ RunSQLRes "CommandOk" Null
|
||
fromRes (Q.ResultOkData res) = do
|
||
csvRows <- resToCSV res
|
||
return $ RunSQLRes "TuplesOk" $ toJSON csvRows
|
||
where
|
||
resToCSV :: PQ.Result -> ExceptT Text IO [[Text]]
|
||
resToCSV r = do
|
||
nr <- liftIO $ PQ.ntuples r
|
||
nc <- liftIO $ PQ.nfields r
|
||
|
||
hdr <- forM [0..pred nc] $ \ic -> do
|
||
colNameBS <- liftIO $ PQ.fname r ic
|
||
maybe (return "unknown") decodeBS colNameBS
|
||
|
||
rows <- forM [0..pred nr] $ \ir ->
|
||
forM [0..pred nc] $ \ic -> do
|
||
cellValBS <- liftIO $ PQ.getvalue r ir ic
|
||
maybe (return "NULL") decodeBS cellValBS
|
||
|
||
return $ hdr:rows
|
||
|
||
decodeBS = either (throwError . T.pack . show) return . TE.decodeUtf8'
|