Safe Haskell	Safe
Language	Haskell2010

System.Serf.Handler

Description

This module provides basic support for implementing Serf event handler programs using Haskell. Serf calls event handlers by executing the specified handler program with information relevant to the handler set in environment variables.

Synopsis

Documentation

data Event #

A union of all possible event types that Serf supports.

Constructors

MemberJoin	An event indicating that members have joined the cluster.
MemberLeave	An event indicating that members have left the cluster.
MemberFailed	An event indicating that members have failed out of the cluster.
User String	A custom event triggered by an agent in the cluster.

Instances

Read Event #
Methods readsPrec :: Int -> ReadS Event # readList :: ReadS [Event] # readPrec :: ReadPrec Event # readListPrec :: ReadPrec [Event] #
Show Event #
Methods showsPrec :: Int -> Event -> ShowS # show :: Event -> String # showList :: [Event] -> ShowS #

data SerfEnv #

All data set in the environment for the event handler. This is the primary way that Serf communicates relevant information to the executing handler.

Constructors

SerfEnv
Fields event :: Event The event that caused the handling program to be executed. selfName :: String The name of the node that is executing the event handler. selfRole :: String The role of the node that is executing the event handler.

Instances

Read SerfEnv #
Methods readsPrec :: Int -> ReadS SerfEnv # readList :: ReadS [SerfEnv] # readPrec :: ReadPrec SerfEnv # readListPrec :: ReadPrec [SerfEnv] #
Show SerfEnv #
Methods showsPrec :: Int -> SerfEnv -> ShowS # show :: SerfEnv -> String # showList :: [SerfEnv] -> ShowS #

getSerfEnv :: IO (Maybe SerfEnv) #

Retrieve all environment info set by Serf, returning Nothing if any Serf environment data is missing.