Haskell Quickstart Guide

MinIO Haskell Client SDK for Amazon S3 Compatible Cloud Storage CIHackageSlack

The MinIO Haskell Client SDK provides simple APIs to access MinIO and any Amazon S3 compatible object storage.

This guide assumes that you have a working Haskell development environment.


Add to your project

Simply add minio-hs to your project’s .cabal dependencies section or if you are using hpack, to your package.yaml file as usual.

Try it out in a REPL

For a cabal based environment

Download the library source and change to the extracted directory:

$ cabal get minio-hs
$ cd minio-hs-1.6.0/ # directory name could be different

Then load the ghci REPL environment with the library and browse the available APIs:

$ cabal repl
ghci> :browse Network.Minio
For a stack based environment

From your home folder or any non-haskell project directory, just run:

stack install minio-hs

Then start an interpreter session and browse the available APIs with:

$ stack ghci
> :browse Network.Minio


The examples folder contains many examples that you can try out and use to learn and to help with developing your own projects.

Quick-Start Example - File Uploader

This example program connects to a MinIO object storage server, makes a bucket on the server and then uploads a file to the bucket.

We will use the MinIO server running at in this example. Feel free to use this service for testing and development. Access credentials are present in the library and are open to the public.


#!/usr/bin/env stack
-- stack --resolver lts-14.11 runghc --package minio-hs --package optparse-applicative --package filepath

-- MinIO Haskell SDK, (C) 2017-2019 MinIO, Inc.
-- Licensed under the Apache License, Version 2.0 (the "License");
-- you may not use this file except in compliance with the License.
-- You may obtain a copy of the License at
-- Unless required by applicable law or agreed to in writing, software
-- distributed under the License is distributed on an "AS IS" BASIS,
-- See the License for the specific language governing permissions and
-- limitations under the License.

{-# LANGUAGE OverloadedStrings   #-}
{-# LANGUAGE ScopedTypeVariables #-}
import           Network.Minio

import           Data.Monoid           ((<>))
import           Data.Text             (pack)
import           Options.Applicative
import           System.FilePath.Posix
import           UnliftIO              (throwIO, try)

import           Prelude

-- | The following example uses minio's play server at
--  The endpoint and associated
-- credentials are provided via the libary constant,
-- > minioPlayCI :: ConnectInfo

-- optparse-applicative package based command-line parsing.
fileNameArgs :: Parser FilePath
fileNameArgs = strArgument
               (metavar "FILENAME"
                <> help "Name of file to upload to AWS S3 or a MinIO server")

cmdParser = info
            (helper <*> fileNameArgs)
             <> progDesc "FileUploader"
             <> header
             "FileUploader - a simple file-uploader program using minio-hs")

main :: IO ()
main = do
  let bucket = "my-bucket"

  -- Parse command line argument
  filepath <- execParser cmdParser
  let object = pack $ takeBaseName filepath

  res <- runMinio minioPlayCI $ do
    -- Make a bucket; catch bucket already exists exception if thrown.
    bErr <- try $ makeBucket bucket Nothing

    -- If the bucket already exists, we would get a specific
    -- `ServiceErr` exception thrown.
    case bErr of
      Left BucketAlreadyOwnedByYou -> return ()
      Left e                       -> throwIO e
      Right _                      -> return ()

    -- Upload filepath to bucket; object name is derived from filepath.
    fPutObject bucket object filepath defaultPutObjectOptions

  case res of
    Left e   -> putStrLn $ "file upload failed due to " ++ show e
    Right () -> putStrLn "file upload succeeded."

Run FileUploader

./FileUploader.hs "path/to/my/file"


Contributors Guide


Download the source
$ git clone
$ cd minio-hs/
Build the package:

With cabal:

$ # Configure cabal for development enabling all optional flags defined by the package.
$ cabal configure --enable-tests --test-show-details=direct -fexamples -fdev -flive-test
$ cabal build

With stack:

$ stack build --test --no-run-tests --flag minio-hs:live-test --flag minio-hs:dev --flag minio-hs:examples
Running tests:

A section of the tests use the remote MinIO Play server at by default. For library development, using this remote server maybe slow. To run the tests against a locally running MinIO live server at http://localhost:9000 with the credentials access_key=minio and secret_key=minio123, just set the environment MINIO_LOCAL to any value (and unset it to switch back to Play).

With cabal:

$ export MINIO_LOCAL=1 # to run live tests against local MinIO server
$ cabal test

With stack:

$ export MINIO_LOCAL=1 # to run live tests against local MinIO server
stack test --flag minio-hs:live-test --flag minio-hs:dev

This will run all the test suites.

Building documentation:
$ cabal haddock
$ # OR
$ stack haddock