The gitson package

[ Tags: benchmark, database, git, json, library, public-domain ] [ Propose Tags ]

A simple document store library for Git + JSON, based on Aeson. Uses command line git. Transactions use flock, so it's safe even across completely separate programs!

[Skip to Readme]


Versions 0.1.0, 0.2.0, 0.2.1, 0.3.0, 0.4.0, 0.4.1, 0.5.0, 0.5.1, 0.5.2
Dependencies aeson, aeson-pretty (>=0.8.0), base (>= && <5), base-compat (>=0.8.0), bytestring, conduit-combinators, conduit-extra, directory, errors, filepath, flock, lifted-base, monad-control, process, transformers [details]
License PublicDomain
Copyright 2014-2015 Greg V <>
Author Greg V
Category Database, JSON, Git
Home page
Source repository head: git clone git://
Uploaded Thu Jul 21 19:02:28 UTC 2016 by myfreeweb
Distributions LTSHaskell:0.5.2, NixOS:0.5.2, Tumbleweed:0.5.2
Downloads 1775 total (13 in the last 30 days)
Rating 0.0 (0 ratings) [clear rating]
  • λ
  • λ
  • λ
Status Docs available [build log]
Last success reported on 2016-11-22 [all 1 reports]
Hackage Matrix CI




Maintainer's Corner

For package maintainers and hackage trustees

Readme for gitson-0.5.2

[back to package description]

gitson Hackage Build Status unlicense

A simple document store library for Git + JSON, based on Aeson. Uses command line git, at least for now. No fancy indexes and stuff, but it does what I need right now. Transactions use flock, so it's safe even across completely separate programs!


{-# LANGUAGE TemplateHaskell #-}

import Gitson
import Gitson.Util (insideDirectory)
import Data.Aeson.TH
import Control.Monad.IO.Class (liftIO)

data Thing = Thing { val :: Int } deriving (Eq, Show)
$(deriveJSON defaultOptions ''Thing) -- there are non-Template ways of doing this, see aeson docs

main :: IO ()
main = do
  -- Creating a new "database," basically mkdir + git init
  createRepo "./content"

  -- Writing data to a "database" happens in transactions
  -- A transaction is committed (write files & git commit)
  -- after the block is executed, just like in SQL databases
  -- Also, transactions are thread-safe
  transaction "./content" $ do
    -- order:    (collection) (key        ) (data)
    saveDocument "things"     "first-thing" Thing {val = 1}
    -- Collections are created automatically, like in MongoDB
    liftIO $ putStrLn "Written first-thing"
    -- You have to use liftIO to do IO actions inside of a transaction!
    -- Because a transaction is a monad transformer, WriterT actually

  -- Reading data
  -- (These are normal IO actions, so if you want
  --  to read inside of a transaction, liftIO.
  --  Note: transaction already includes insideDirectory!
  --  Warning: you can't read what you've written in the current transaction!!!
  --  You can only read what's been written before the transaction began.)
  insideDirectory "./content" $ do
    colls <- listCollections
          -- ["things"]
    keys <- listDocumentKeys "things"
         -- ["first-thing"]
    first-thing <- readDocument "things" "first-thing" :: IO (Maybe Thing)
         -- Just Thing {val = 1}
    things <- readEntries "things" :: IO [Thing]
           -- [Thing {val = 1}]

  -- Note: insideDirectory is just a function that changes
  -- the current directory, executes an action and changes it back.
  -- You can use reading actions without it, like this:
  keys <- listDocumentKeys "./content/things"

  -- And now, some bells and whistles:
  -- Numeric id support
  transaction "./content" $ do
    saveNextDocument "things" "hello-world" Thing {val = 1}
    -- will save to things/000001-hello-world.json
  insideDirectory "./content" $ do
    thing <- readDocumentById "things" 1
    same-thing <- readDocumentByName "things" "hello-world"
    -- both will read from things/000001-hello-world.json
    i <- documentIdFromName "things" "hello-world"
      -- 1
    n <- documentNameFromId "things" 1
      -- "hello-world"


Use stack to build.
Use ghci to run tests quickly with :test (see the .ghci file).

``bash $ stack build

$ stack test && rm tests.tix

$ stack bench

$ stack ghci --ghc-options="-fno-hpc" ``


Please feel free to submit pull requests! Bugfixes and simple non-breaking improvements will be accepted without any questions :-)

By participating in this project you agree to follow the Contributor Code of Conduct.


This is free and unencumbered software released into the public domain.
For more information, please refer to the UNLICENSE file or