Keter.PortManager

Types

type Port = Int

A port for an individual app to listen on.

type Host = String

A virtual host we want to serve content from.

data PortManager

An abstract type which can accept commands and sends them to a background nginx thread.

data PortEntry

Constructors

PEPort Port

PEStatic FilePath

PERedirect ByteString

Settings

data Settings

Controls execution of the nginx thread. Follows the settings type pattern. See: http://www.yesodweb.com/book/settings-types.

Instances

FromJSON Settings

Default Settings

portRange :: Settings -> [Port]

Which ports to assign to apps. Default: 4000-4999

Actions

getPort :: PortManager -> KIO (Either SomeException Port)

Gets an unassigned port number.

releasePort :: PortManager -> Port -> KIO ()

Inform the nginx thread that the given port number is no longer being used, and may be reused by a new process. Note that recycling puts the new ports at the end of the queue (FIFO), so that if an application holds onto the port longer than expected, there should be no issues.

addEntry :: PortManager -> Host -> PortEntry -> KIO ()

Add a new entry to the configuration for the given hostname and reload nginx. Will overwrite any existing configuration for the given host. The second point is important: it is how we achieve zero downtime transitions between an old and new version of an app.

removeEntry :: PortManager -> Host -> KIO ()

Remove an entry from the configuration and reload nginx.

lookupPort :: PortManager -> ByteString -> KIO (Maybe PortEntry)

Initialize

start :: Settings -> KIO (Either SomeException PortManager)

Start running a separate thread which will accept commands and modify Nginx's behavior accordingly.