Database.MongoDB.Connection

Connect to a single server or a replica set of servers

Util

type IOE = ErrorT IOError IO

IO monad with explicit error

runIOE :: ErrorT IOError IO a -> IO a

Run action while catching explicit error and rethrowing in IO monad

Connection

type Pipe = Pipeline Response Message

Thread-safe TCP connection with pipelined requests

close :: Pipeline i o -> IO ()

Close pipe and underlying connection

isClosed :: Pipeline i o -> IO Bool

Server

data Host

Constructors

Host HostName PortID

Instances

Eq Host

Ord Host

Show Host

data PortID

Constructors

Service String

PortNumber PortNumber

UnixSocket String

Instances

Eq PortID

Ord PortID

Show PortID

defaultPort :: PortID

Default MongoDB port = 27017

host :: HostName -> Host

Host on defaultPort

showHostPort :: Host -> String

Display host as "host:port" TODO: Distinguish Service and UnixSocket port

readHostPort :: String -> Host

Read string "hostname:port" as Host hostname (PortNumber port) or "hostname" as host hostname (default port). Error if string does not match either syntax.

readHostPortM :: Monad m => String -> m Host

Read string "hostname:port" as Host hosthame (PortNumber port) or "hostname" as host hostname (default port). Fail if string does not match either syntax. TODO: handle Service and UnixSocket port

connect :: Host -> IOE Pipe

Connect to Host returning pipelined TCP connection. Throw IOError if problem connecting.

Replica Set

type ReplicaSetName = UString

openReplicaSet :: (ReplicaSetName, [Host]) -> IOE ReplicaSet

Open connections (on demand) to servers in replica set. Supplied hosts is seed list. At least one of them must be a live member of the named replica set, otherwise fail.

data ReplicaSet

Maintains a connection (created on demand) to each server in the named replica set

primary :: ReplicaSet -> IOE Pipe

Return connection to current primary of replica set. Fail if no primary available.

secondaryOk :: ReplicaSet -> IOE Pipe

Return connection to a random secondary, or primary if no secondaries available.

closeReplicaSet :: ReplicaSet -> IO ()

Close all connections to replica set