The daemons package

[ Tags: control, gpl, library, network, program, system ] [ Propose Tags ]

Control.Pipe.C3 provides simple RPC-like wrappers for pipes.

Control.Pipe.Serialize provides serialization and incremental deserialization pipes.

Control.Pipe.Socket provides functions to setup pipes around sockets.

System.Daemon provides a high-level interface to starting daemonized programs that are controlled through sockets.

System.Posix.Daemon provides a low-level interface to starting, and controlling detached jobs.

See the README.md file and the homepage for details.


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Properties

Versions 0.1.0, 0.1.1, 0.1.2, 0.2.0, 0.2.1
Change log NEWS.md
Dependencies base (==4.*), bytestring, cereal, containers, data-default, directory, filepath, ghc-prim, network, pipes, transformers, unix [details]
License GPL-3
Author Alexandru Scvortov <scvalex@gmail.com>
Maintainer scvalex@gmail.com
Category Text
Home page https://github.com/scvalex/daemons
Source repository head: git clone git://github.com/scvalex/daemons.git
Uploaded Wed Aug 15 02:16:55 UTC 2012 by AlexandruScvortov
Distributions NixOS:0.2.1
Executables queue, addone, memo
Downloads 2035 total (18 in the last 30 days)
Rating 0.0 (0 ratings) [clear rating]
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Status Docs uploaded by user
Build status unknown [no reports yet]
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Readme for daemons-0.1.0

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daemons

Daemons in Haskell made fun and easy

Example

Here's AddOne, a simple daemon that waits for a number and responds with the incremented number.

import Data.Default ( def )
import System.Environment ( getArgs )
import System.Daemon

addOne :: Int -> IO Int
addOne n = return (n + 1)

main :: IO ()
main = do
    startDaemon "addOne" def addOne
    [n] <- getArgs
    res <- runClient "localhost" 5000 ((read n) :: Int)
    print (res :: Maybe Int)

Running it, we see:

% addone 22
Just 23
% addone 41
Just 42

The two important functions above are startDaemon, which checks if a daemon named addOne is already running, and starts it if not, and runClient which connects to the daemon running on localhost:5000, passes it a number, and waits for the response.

For a less trivial example, see the in-memory key-value store, Memo.

For an example that uses the streaming interface of daemons, see PMTQ (Poor Man's Task Queue).

Installation

This package is on Hackage. To install it, run:

cabal update
cabal install daemons

Modules

  • Control.Pipe.C3 provides simple RPC-like wrappers for pipes.

  • Control.Pipe.Serialize provides pipes to serialize and deserialize streams of strict ByteStrings using cereal.

  • Control.Pipe.Socket provides functions to setup strict ByteString pipes around sockets.

  • System.Daemon provides a high-level interface to starting daemonized programs that are controlled through sockets.

  • System.Posix.Daemon provides a low-level interface to starting, and controlling detached jobs.

See also