diff --git a/hzk.cabal b/hzk.cabal --- a/hzk.cabal +++ b/hzk.cabal @@ -1,7 +1,7 @@ name: hzk author: DiegoSouza license: BSD3 -version: 2.0.0 +version: 2.1.0 category: Database homepage: http://github.com/dgvncsz0f/hzk synopsis: Haskell client library for Apache Zookeeper @@ -21,13 +21,16 @@ include-dirs: /usr/include/zookeeper build-depends: base (>= 4 && < 5) , bytestring (>= 0.10 && < 1) + , resource-pool + , time other-modules: Database.Zookeeper.CApi , Database.Zookeeper.Types hs-source-dirs: src exposed-modules: Database.Zookeeper + , Database.Zookeeper.Pool extra-libraries: zookeeper_mt default-language: Haskell2010 - default-extensions: Safe +-- default-extensions: Safe test-suite test-zookeeper type: exitcode-stdio-1.0 @@ -41,6 +44,8 @@ , tasty (>= 0.3 && < 1) , bytestring (>= 0.10 && < 1) , tasty-hunit (>= 0.2 && < 1) + , resource-pool + , time hs-source-dirs: src extra-libraries: zookeeper_mt default-language: Haskell2010 diff --git a/src/Database/Zookeeper/Pool.hs b/src/Database/Zookeeper/Pool.hs new file mode 100644 --- /dev/null +++ b/src/Database/Zookeeper/Pool.hs @@ -0,0 +1,114 @@ +{-# LANGUAGE TupleSections #-} + +-- This file is part of zhk +-- +-- All rights reserved. +-- +-- Redistribution and use in source and binary forms, with or without modification, +-- are permitted provided that the following conditions are met: +-- +-- Redistributions of source code must retain the above copyright notice, this +-- list of conditions and the following disclaimer. +-- +-- Redistributions in binary form must reproduce the above copyright notice, this +-- list of conditions and the following disclaimer in the documentation and/or +-- other materials provided with the distribution. +-- +-- Neither the name of the {organization} nor the names of its +-- contributors may be used to endorse or promote products derived from +-- this software without specific prior written permission. +-- +-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND +-- ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +-- WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE +-- DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR +-- ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES +-- (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +-- LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON +-- ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +-- (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS +-- SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +-------------------------------------------------------------------------------- +-- | +-- Module : Database.Zookeeper.Pool +-- Copyright : (C) 2013 Diego Souza +-- License : BSD-style (see the file LICENSE) +-- +-- Maintainer : Diego Souza +-- Stability : experimental +-- +-- Zookeeper client library +-------------------------------------------------------------------------------- +module Database.Zookeeper.Pool + ( -- * Description + -- $description + + -- * Example + -- $example + + -- * Notes + -- $notes + + -- * Connection + connect + ) where + +import Foreign.C +import Foreign.Safe +import Database.Zookeeper.CApi +import Database.Zookeeper.Types +import qualified Data.Pool as P +import Data.Time + +-- | Connects to the zookeeper cluster. This function may throw an +-- exception if a valid zookeeper handle could not be created. +-- +-- The connection is terminated right before this function returns. +connect :: String + -- ^ The zookeeper endpoint to connect to. This is given + -- as-is to the underlying C API. Briefly, host:port + -- separated by comma. At the end, you may define an + -- optional chroot, like the following: + -- localhost:2181,localhost:2182/foobar + -> Timeout + -- ^ The session timeout (milliseconds) + -> Maybe Watcher + -- ^ The global watcher function. When notifications are + -- triggered this function will be invoked + -> Maybe ClientID + -- ^ The id of a previously established session that + -- this client will be reconnecting to + -> Int + -- ^ The number of stripes (distinct sub-pools) to maintain. + -- The smallest acceptable value is 1. + -> NominalDiffTime + -- ^ Amount of time for which an unused resource is kept open. + -- The smallest acceptable value is 0.5 seconds. + -- + -- The elapsed time before destroying a resource may be a little + -- longer than requested, as the reaper thread wakes at 1-second + -- intervals. + -> Int + -- ^ Maximum number of resources to keep open per stripe. The + -- smallest acceptable value is 1. + -- + -- Requests for resources will block if this limit is reached on a + -- single stripe, even if other stripes have idle resources + -- available. + -> IO (P.Pool Zookeeper) +connect endpoint timeout watcher clientId numStripes idleTime maxResources = do + P.createPool + (open endpoint timeout watcher) + close + numStripes idleTime maxResources + where + open endpoint' timeout' watcher' = do + withCString endpoint' $ \strPtr -> do + cWatcher <- wrapWatcher watcher' + zh <- throwIfNull "zookeeper_init" $ c_zookeeperInit strPtr cWatcher (fromIntegral timeout') cClientIdPtr nullPtr 0 + return (Zookeeper zh) + close (Zookeeper zh) = c_zookeeperClose zh + cClientIdPtr = case clientId of + Nothing -> nullPtr + Just (ClientID ptr) -> ptr