Montage: a riak resolution proxy
Even Rocky had a montage...
Install
Built and tested with ghc 7.4.1
Install the non-hackage dependencies:
git clone git@github.com:wmoss/StatsWeb.git cd StatsWeb && cabal install git clone git@github.com:bumptech/riak-haskell-client.git cd riak-haskell-client && cabal install
From montage/ execute:
cabal install
We recommend using a sandbox, hsenv is particularly good.
Configuration
The montage proxy is port configurable (here given the Config handle set to 7078), with riak running on 8087:
import Network.Riak (defaultClient, connect, disconnect, Client(port), Connection) import Data.Conduit.Pool (Pool, createPool) import Network.Riak.Montage main :: IO () main = do mainPool <- createPool (connect $ defaultClient {port = "8087"}) disconnect 1 -- stripes 10 -- timeout 300 -- max connections let cfg' = cfg { proxyPort = 7078 } runDaemon (cfg' :: Config ResObject) mainPool
- ResObject is a concrete datatype you define. For Montage to work with this datatype, you must define:
- translations from bytestring -> datatype, datatype -> bytestring,
- methods for resolving siblings,
- and how to obtain a bytestring key from values in the datatype
See examples/ for a definition of ResObject and how to implement (1), (2), and (3).
You can also set the mainPool argument to be a datatype with more than one pool, in case particular buckets have such variable resolution times that you want to isolate your bucket fetches:
data Pools = Pools { poolA :: Pool Connection , poolB :: Pool Connection } instance Poolable Pools where chooser pools "bucketA" = poolA pools chooser pools "bucketB" = poolB pools chooser pools "bucketC" = poolC pools
For a single pool, like mainPool, you're also required to define its datatype as an instance of Poolable, such that the bucket doesn't matter:
instance Poolable (Pool Connection) where chooser pool _ = pool
You can also a set the cfg field 'logger' to a logging function that fits the type signature:
logger :: B.Bytestring -> Maybe Double -> Value -> IO () logger errorType duration val = -- your defintion
where errorType is filled in by the Montage exception handler with the type of exception (useful as a prefix), duration is a timestamp Montage may provide (depending on where the error occurs), and val is JSON that Montage constructs with details about the error.
Since Montage provides these values, your logger would simply format the arguments and broadcasts them to a location of your choice. The default logger simply concatenates the arguments and broadcasts to stderr.
Examples
To setup the examples, first download hprotoc:
cabal install hprotoc
Then execute:
cd examples && hprotoc user.proto
Then:
cd examples && runhaskell basic_proxy.hs
For client examples to run against the basic_proxy, see github.com/bumptech/montage-haskell-client/examples
More
See the haddock documentation for type-signatures, descriptions, and source of client functions.