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a805f4d185
https://github.com/hasura/graphql-engine-mono/pull/1553 GitOrigin-RevId: b67dc40e54496ed6ad6c85755cf66745664416f7
76 lines
3.0 KiB
Haskell
76 lines
3.0 KiB
Haskell
{-| This module (along with the various @Hasura.RQL.DDL.Schema.*@ modules) provides operations to
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load and modify the Hasura catalog and schema cache.
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* The /catalog/ refers to the set of PostgreSQL tables and views that store all schema information
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known by Hasura. This includes any tracked Postgres tables, views, and functions, all remote
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schemas, and any additionaly Hasura-specific information such as permissions and relationships.
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Primitive functions for loading and modifying the catalog are defined in
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"Hasura.RQL.DDL.Schema.Catalog", but most uses are wrapped by other functions to synchronize
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catalog information with the information in the schema cache.
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* The /schema cache/ is a process-global value of type 'SchemaCache' that stores an in-memory
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representation of the data stored in the catalog. The in-memory representation is not identical
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to the data in the catalog, since it has some post-processing applied to it in order to make it
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easier to consume for other parts of the system, such as GraphQL schema generation. For example,
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although column information is represented by 'RawColumnInfo', the schema cache contains
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“processed” 'ColumnInfo' values, instead.
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Ultimately, the catalog is the source of truth for all information contained in the schema
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cache, but to avoid rebuilding the entire schema cache on every change to the catalog, various
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functions incrementally update the cache when they modify the catalog.
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-}
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module Hasura.RQL.DDL.Schema
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( module M
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, RunSQLRes(..)
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) where
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import Hasura.Prelude
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import qualified Data.Text.Encoding as TE
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import qualified Database.PG.Query as Q
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import qualified Database.PostgreSQL.LibPQ as PQ
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import Data.Aeson
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import Data.Aeson.TH
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import Hasura.RQL.DDL.Schema.Cache as M
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import Hasura.RQL.DDL.Schema.Catalog as M
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import Hasura.RQL.DDL.Schema.Function as M
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import Hasura.RQL.DDL.Schema.Rename as M
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import Hasura.RQL.DDL.Schema.Table as M
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data RunSQLRes
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= RunSQLRes
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{ rrResultType :: !Text
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, rrResult :: !Value
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} deriving (Show, Eq)
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$(deriveJSON hasuraJSON ''RunSQLRes)
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instance Q.FromRes RunSQLRes where
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fromRes (Q.ResultOkEmpty _) =
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return $ RunSQLRes "CommandOk" Null
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fromRes (Q.ResultOkData res) = do
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csvRows <- resToCSV res
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return $ RunSQLRes "TuplesOk" $ toJSON csvRows
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where
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resToCSV :: PQ.Result -> ExceptT Text IO [[Text]]
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resToCSV r = do
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nr <- liftIO $ PQ.ntuples r
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nc <- liftIO $ PQ.nfields r
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hdr <- forM [0..pred nc] $ \ic -> do
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colNameBS <- liftIO $ PQ.fname r ic
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maybe (return "unknown") decodeBS colNameBS
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rows <- forM [0..pred nr] $ \ir ->
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forM [0..pred nc] $ \ic -> do
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cellValBS <- liftIO $ PQ.getvalue r ir ic
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maybe (return "NULL") decodeBS cellValBS
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return $ hdr:rows
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decodeBS = either (throwError . tshow) return . TE.decodeUtf8'
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