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cb9f822fc0
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/8595 GitOrigin-RevId: b3b7dec8504fe4daf324125e4017fa7d1945b3ca
73 lines
2.9 KiB
Haskell
73 lines
2.9 KiB
Haskell
{-# LANGUAGE TemplateHaskell #-}
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-- | 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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--
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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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--
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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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--
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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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--
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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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module Hasura.RQL.DDL.Schema
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( module M,
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RunSQLRes (..),
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)
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where
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import Data.Aeson
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import Data.Aeson.TH (deriveJSON)
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import Data.Text.Encoding qualified as TE
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import Database.PG.Query qualified as PG
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import Database.PostgreSQL.LibPQ qualified as PQ
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import Hasura.Prelude
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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.Rename as M
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import Hasura.RQL.DDL.Schema.Table as M
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data RunSQLRes = RunSQLRes
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{ rrResultType :: Text,
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rrResult :: Value
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}
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deriving (Show, Eq)
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$(deriveJSON hasuraJSON ''RunSQLRes)
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instance PG.FromRes RunSQLRes where
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fromRes (PG.ResultOkEmpty _) =
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return $ RunSQLRes "CommandOk" Null
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fromRes (PG.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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