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.. | ||
apps | ||
src/System/Nix/Store | ||
tests | ||
CHANGELOG.md | ||
hnix-store-db.cabal | ||
LICENSE | ||
README.lhs | ||
README.md |
hnix-store-db
Nix SQLite database implementation.
Only read-only functionality provided for
database schema version 10
.
API
The interface is experimental and might change wildly.
Example
This example is runnable via cabal run db-readme
.
{-# LANGUAGE OverloadedStrings #-}
import Data.Default.Class (Default(def))
import qualified Control.Monad
import qualified Control.Monad.IO.Class
import qualified Database.Esqueleto.Experimental
import qualified System.Nix.StorePath
import qualified System.Nix.Store.DB.Run
import qualified System.Nix.Store.DB.Schema
import System.Nix.Store.DB.Query
main :: IO ()
main = do
System.Nix.Store.DB.Run.runSystemSqlite $ do
(paths, refs, drvOuts) <- queryEverything
Control.Monad.IO.Class.liftIO $ do
putStrLn $ "Stats: "
let stat name v = putStrLn $ "- " ++ name ++ ": " ++ show (length v)
stat "ValidPath(s)" paths
stat "Ref(s)" refs
stat "DerivationOutput(s)" drvOuts
maybeValidPath <- queryOneValidDerivationEntity
case maybeValidPath of
Nothing -> pure ()
Just validPathEntity -> do
let pth =
System.Nix.Store.DB.Schema.validPathPath
$ Database.Esqueleto.Experimental.entityVal validPathEntity
(same, samePath, references, referrers, validDerivers, outputs) <- (,,,,,)
<$> queryPathInfo pth
<*> queryPathFromHashPart def (System.Nix.StorePath.storePathHash pth)
<*> queryReferences validPathEntity
<*> queryReferrers pth
<*> queryValidDerivers pth
<*> queryDerivationOutputs validPathEntity
Control.Monad.unless (same == Just (Database.Esqueleto.Experimental.entityVal validPathEntity))
$ error "queryPathInfo failed to roundtrip"
Control.Monad.unless (samePath == Just pth)
$ error "queryPathFromHashPart failed to roundtrip"
Control.Monad.IO.Class.liftIO $ do
putStrLn $ "References: "
print references
putStrLn $ "Referrers: "
print referrers
putStrLn $ "Valid derivers: "
print validDerivers
putStrLn $ "Derivation outputs: "
print outputs
pure ()