Propellor

When propellor runs on a Host, it ensures that its Properties are satisfied, taking action as necessary when a Property is not currently satisfied.

A simple propellor program example:

import Propellor
import qualified Propellor.Property.File as File
import qualified Propellor.Property.Apt as Apt

main :: IO ()
main = defaultMain hosts

hosts :: [Host]
hosts = [example]

example :: Host
example = host "example.com" $ props
    & Apt.installed ["mydaemon"]
    & "/etc/mydaemon.conf" `File.containsLine` "secure=1"
      `onChange` cmdProperty "service" ["mydaemon", "restart"]
    ! Apt.installed ["unwantedpackage"]

See config.hs for a more complete example, and clone Propellor's git repository for a deployable system using Propellor: git clone git://git.joeyh.name/propellor

Core data types

data Host

Everything Propellor knows about a system: Its hostname, properties and their collected info.

Constructors

Host

Fields

hostName :: HostName

hostProperties :: [ChildProperty]

hostInfo :: Info

Instances

Show Host

IsContainer Host

Conductable Host

MonadReader Host Propellor

Conductable [Host]

data Property metatypes

The core data type of Propellor, this represents a property that the system should have, with a descrition, and an action to ensure it has the property. that have the property.

There are different types of properties that target different OS's, and so have different metatypes. For example: "Property DebianLike" and "Property FreeBSD".

Also, some properties have associated Info, which is indicated in their type: "Property (HasInfo + DebianLike)"

There are many associated type families, which are mostly used internally, so you needn't worry about them.

Constructors

Property metatypes Desc (Propellor Result) Info [ChildProperty]

Instances

TightenTargets Property

Checkable Property i

Show (Property metatypes)

IsProp (Property metatypes)

((~) CheckCombine (CheckCombinable k x y) CanCombine, SingI [k] (Combine k x y)) => Combines (Property (MetaTypes [k] x)) (Property (MetaTypes [k] y))

((~) CheckCombine (CheckCombinable k x y) CanCombine, SingI [k] (Combine k x y)) => Combines (Property (MetaTypes [k] x)) (RevertableProperty (MetaTypes [k] y) (MetaTypes k y'))

((~) CheckCombine (CheckCombinable k x y) CanCombine, SingI [k] (Combine k x y)) => Combines (RevertableProperty (MetaTypes [k] x) (MetaTypes k x')) (Property (MetaTypes [k] y))

type CombinedType (Property (MetaTypes [k] x)) (Property (MetaTypes [k] y)) = Property (MetaTypes [k] (Combine k x y))

type CombinedType (Property (MetaTypes [k] x)) (RevertableProperty (MetaTypes [k] y) (MetaTypes k1 y')) = Property (MetaTypes [k] (Combine k x y))

type CombinedType (RevertableProperty (MetaTypes [k] x) (MetaTypes k1 x')) (Property (MetaTypes [k] y)) = Property (MetaTypes [k] (Combine k x y))

data RevertableProperty setupmetatypes undometatypes

A property that can be reverted. The first Property is run normally and the second is run when it's reverted.

Constructors

RevertableProperty

Fields

setupRevertableProperty :: Property setupmetatypes

undoRevertableProperty :: Property undometatypes

Instances

((~) CheckCombine (CheckCombinable k x y) CanCombine, SingI [k] (Combine k x y)) => Combines (Property (MetaTypes [k] x)) (RevertableProperty (MetaTypes [k] y) (MetaTypes k y'))

Show (RevertableProperty setupmetatypes undometatypes)

IsProp (RevertableProperty setupmetatypes undometatypes)

((~) CheckCombine (CheckCombinable k x y) CanCombine, SingI [k] (Combine k x y)) => Combines (RevertableProperty (MetaTypes [k] x) (MetaTypes k x')) (Property (MetaTypes [k] y))

((~) CheckCombine (CheckCombinable k x y) CanCombine, (~) CheckCombine (CheckCombinable k1 x' y') CanCombine, SingI [k] (Combine k x y), SingI [k1] (Combine k1 x' y')) => Combines (RevertableProperty (MetaTypes [k] x) (MetaTypes [k] x')) (RevertableProperty (MetaTypes [k] y) (MetaTypes [k] y'))

type CombinedType (Property (MetaTypes [k] x)) (RevertableProperty (MetaTypes [k] y) (MetaTypes k1 y')) = Property (MetaTypes [k] (Combine k x y))

type CombinedType (RevertableProperty (MetaTypes [k] x) (MetaTypes k1 x')) (Property (MetaTypes [k] y)) = Property (MetaTypes [k] (Combine k x y))

type CombinedType (RevertableProperty (MetaTypes [k] x) (MetaTypes [k1] x')) (RevertableProperty (MetaTypes [k] y) (MetaTypes [k1] y')) = RevertableProperty (MetaTypes [k] (Combine k x y)) (MetaTypes [k1] (Combine k1 x' y'))

module Propellor.Types

Config file

defaultMain :: [Host] -> IO ()

Runs propellor on hosts, as controlled by command-line options.

host :: HostName -> Props metatypes -> Host

Defines a host and its properties.

host "example.com" $ props
	& someproperty
	! oldproperty
	& otherproperty

(&) :: (IsProp p, MetaTypes y ~ GetMetaTypes p, CheckCombinable x y ~ CanCombine) => Props (MetaTypes x) -> p -> Props (MetaTypes (Combine x y)) infixl 1

Adds a property to a Props.

Can add Properties and RevertableProperties

(!) :: (CheckCombinable x z ~ CanCombine) => Props (MetaTypes x) -> RevertableProperty (MetaTypes y) (MetaTypes z) -> Props (MetaTypes (Combine x z)) infixl 1

Adds a property in reverted form.

Propertries

Properties are often combined together in your propellor configuration. For example:

"/etc/foo/config" `File.containsLine` "bar=1"
	`requires` File.dirExists "/etc/foo"

requires :: Combines x y => x -> y -> CombinedType x y

Indicates that the first property depends on the second, so before the first is ensured, the second must be ensured.

The combined property uses the description of the first property.

before :: Combines x y => x -> y -> CombinedType x y

Combines together two properties, resulting in one property that ensures the first, and if the first succeeds, ensures the second.

The combined property uses the description of the first property.

onChange :: Combines x y => x -> y -> CombinedType x y

Whenever a change has to be made for a Property, causes a hook Property to also be run, but not otherwise.

describe :: IsProp p => p -> Desc -> p

Changes the description of a property.

module Propellor.Property

Everything you need to build your own properties, and useful property combinators

module Propellor.Property.Cmd

Properties to run shell commands

module Propellor.Info

Properties that set Info

module Propellor.Property.List

Combining a list of properties into a single property

module Propellor.Types.PrivData

Private data access for properties