526 lines
16 KiB
Haskell
526 lines
16 KiB
Haskell
{-# LANGUAGE BangPatterns #-}
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-- | Docker support for propellor
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--
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-- The existance of a docker container is just another Property of a system,
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-- which propellor can set up. See config.hs for an example.
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module Propellor.Property.Docker (
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-- * Host properties
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installed,
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configured,
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container,
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docked,
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memoryLimited,
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garbageCollected,
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Image,
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ContainerName,
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-- * Container configuration
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dns,
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hostname,
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name,
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publish,
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expose,
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user,
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volume,
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volumes_from,
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workdir,
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memory,
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cpuShares,
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link,
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ContainerAlias,
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-- * Internal use
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chain,
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) where
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import Propellor
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import Propellor.SimpleSh
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import Propellor.Types.Attr
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import qualified Propellor.Property.File as File
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import qualified Propellor.Property.Apt as Apt
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import qualified Propellor.Property.Docker.Shim as Shim
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import Utility.SafeCommand
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import Utility.Path
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import Control.Concurrent.Async hiding (link)
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import System.Posix.Directory
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import System.Posix.Process
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import Data.List
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import Data.List.Utils
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import qualified Data.Set as S
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installed :: Property
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installed = Apt.installed ["docker.io"]
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-- | Configures docker with an authentication file, so that images can be
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-- pushed to index.docker.io. Optional.
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configured :: Property
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configured = property "docker configured" go `requires` installed
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where
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go = withPrivData DockerAuthentication $ \cfg -> ensureProperty $
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"/root/.dockercfg" `File.hasContent` (lines cfg)
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-- | A short descriptive name for a container.
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-- Should not contain whitespace or other unusual characters,
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-- only [a-zA-Z0-9_-] are allowed
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type ContainerName = String
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-- | Starts accumulating the properties of a Docker container.
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--
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-- > container "web-server" "debian"
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-- > & publish "80:80"
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-- > & Apt.installed {"apache2"]
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-- > & ...
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container :: ContainerName -> Image -> Host
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container cn image = Host hn [] attr
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where
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attr = dockerAttr $ mempty { _dockerImage = Val image }
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hn = cn2hn cn
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cn2hn :: ContainerName -> HostName
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cn2hn cn = cn ++ ".docker"
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-- | Ensures that a docker container is set up and running, finding
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-- its configuration in the passed list of hosts.
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--
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-- The container has its own Properties which are handled by running
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-- propellor inside the container.
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--
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-- Additionally, the container can have DNS attributes, such as a CNAME.
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-- These become attributes of the host(s) it's docked in.
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--
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-- Reverting this property ensures that the container is stopped and
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-- removed.
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docked
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:: [Host]
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-> ContainerName
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-> RevertableProperty
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docked hosts cn = RevertableProperty
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((maybe id exposeDnsAttrs mhost) (go "docked" setup))
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(go "undocked" teardown)
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where
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go desc a = property (desc ++ " " ++ cn) $ do
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hn <- asks hostName
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let cid = ContainerId hn cn
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ensureProperties [findContainer mhost cid cn $ a cid]
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mhost = findHost hosts (cn2hn cn)
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setup cid (Container image runparams) =
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provisionContainer cid
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`requires`
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runningContainer cid image runparams
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`requires`
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installed
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teardown cid (Container image _runparams) =
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combineProperties ("undocked " ++ fromContainerId cid)
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[ stoppedContainer cid
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, property ("cleaned up " ++ fromContainerId cid) $
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liftIO $ report <$> mapM id
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[ removeContainer cid
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, removeImage image
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]
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]
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exposeDnsAttrs :: Host -> Property -> Property
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exposeDnsAttrs (Host _ _ containerattr) p = combineProperties (propertyDesc p) $
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p : map addDNS (S.toList $ _dns containerattr)
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findContainer
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:: Maybe Host
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-> ContainerId
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-> ContainerName
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-> (Container -> Property)
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-> Property
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findContainer mhost cid cn mk = case mhost of
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Nothing -> cantfind
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Just h -> maybe cantfind mk (mkContainer cid h)
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where
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cantfind = containerDesc cid $ property "" $ do
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liftIO $ warningMessage $
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"missing definition for docker container \"" ++ cn2hn cn
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return FailedChange
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mkContainer :: ContainerId -> Host -> Maybe Container
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mkContainer cid@(ContainerId hn _cn) h = Container
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<$> fromVal (_dockerImage attr)
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<*> pure (map (\a -> a hn) (_dockerRunParams attr))
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where
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attr = _dockerattr $ hostAttr h'
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h' = h
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-- expose propellor directory inside the container
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& volume (localdir++":"++localdir)
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-- name the container in a predictable way so we
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-- and the user can easily find it later
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& name (fromContainerId cid)
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-- | Causes *any* docker images that are not in use by running containers to
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-- be deleted. And deletes any containers that propellor has set up
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-- before that are not currently running. Does not delete any containers
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-- that were not set up using propellor.
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--
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-- Generally, should come after the properties for the desired containers.
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garbageCollected :: Property
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garbageCollected = propertyList "docker garbage collected"
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[ gccontainers
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, gcimages
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]
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where
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gccontainers = property "docker containers garbage collected" $
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liftIO $ report <$> (mapM removeContainer =<< listContainers AllContainers)
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gcimages = property "docker images garbage collected" $ do
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liftIO $ report <$> (mapM removeImage =<< listImages)
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-- | Configures the kernel to respect docker memory limits.
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--
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-- This assumes the system boots using grub 2. And that you don't need any
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-- other GRUB_CMDLINE_LINUX_DEFAULT settings.
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--
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-- Only takes effect after reboot. (Not automated.)
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memoryLimited :: Property
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memoryLimited = "/etc/default/grub" `File.containsLine` cfg
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`describe` "docker memory limited"
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`onChange` cmdProperty "update-grub" []
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where
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cmdline = "cgroup_enable=memory swapaccount=1"
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cfg = "GRUB_CMDLINE_LINUX_DEFAULT=\""++cmdline++"\""
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data Container = Container Image [RunParam]
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-- | Parameters to pass to `docker run` when creating a container.
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type RunParam = String
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-- | A docker image, that can be used to run a container.
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type Image = String
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-- | Set custom dns server for container.
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dns :: String -> Property
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dns = runProp "dns"
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-- | Set container host name.
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hostname :: String -> Property
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hostname = runProp "hostname"
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-- | Set name for container. (Normally done automatically.)
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name :: String -> Property
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name = runProp "name"
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-- | Publish a container's port to the host
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-- (format: ip:hostPort:containerPort | ip::containerPort | hostPort:containerPort)
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publish :: String -> Property
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publish = runProp "publish"
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-- | Expose a container's port without publishing it.
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expose :: String -> Property
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expose = runProp "expose"
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-- | Username or UID for container.
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user :: String -> Property
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user = runProp "user"
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-- | Mount a volume
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-- Create a bind mount with: [host-dir]:[container-dir]:[rw|ro]
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-- With just a directory, creates a volume in the container.
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volume :: String -> Property
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volume = runProp "volume"
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-- | Mount a volume from the specified container into the current
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-- container.
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volumes_from :: ContainerName -> Property
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volumes_from cn = genProp "volumes-from" $ \hn ->
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fromContainerId (ContainerId hn cn)
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-- | Work dir inside the container.
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workdir :: String -> Property
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workdir = runProp "workdir"
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-- | Memory limit for container.
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-- Format: <number><optional unit>, where unit = b, k, m or g
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--
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-- Note: Only takes effect when the host has the memoryLimited property
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-- enabled.
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memory :: String -> Property
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memory = runProp "memory"
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-- | CPU shares (relative weight).
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--
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-- By default, all containers run at the same priority, but you can tell
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-- the kernel to give more CPU time to a container using this property.
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cpuShares :: Int -> Property
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cpuShares = runProp "cpu-shares" . show
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-- | Link with another container on the same host.
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link :: ContainerName -> ContainerAlias -> Property
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link linkwith calias = genProp "link" $ \hn ->
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fromContainerId (ContainerId hn linkwith) ++ ":" ++ calias
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-- | A short alias for a linked container.
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-- Each container has its own alias namespace.
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type ContainerAlias = String
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-- | A container is identified by its name, and the host
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-- on which it's deployed.
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data ContainerId = ContainerId HostName ContainerName
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deriving (Eq, Read, Show)
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-- | Two containers with the same ContainerIdent were started from
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-- the same base image (possibly a different version though), and
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-- with the same RunParams.
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data ContainerIdent = ContainerIdent Image HostName ContainerName [RunParam]
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deriving (Read, Show, Eq)
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toContainerId :: String -> Maybe ContainerId
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toContainerId s
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| myContainerSuffix `isSuffixOf` s = case separate (== '.') (desuffix s) of
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(cn, hn)
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| null hn || null cn -> Nothing
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| otherwise -> Just $ ContainerId hn cn
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| otherwise = Nothing
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where
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desuffix = reverse . drop len . reverse
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len = length myContainerSuffix
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fromContainerId :: ContainerId -> String
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fromContainerId (ContainerId hn cn) = cn++"."++hn++myContainerSuffix
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containerHostName :: ContainerId -> HostName
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containerHostName (ContainerId _ cn) = cn2hn cn
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myContainerSuffix :: String
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myContainerSuffix = ".propellor"
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containerDesc :: ContainerId -> Property -> Property
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containerDesc cid p = p `describe` desc
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where
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desc = "[" ++ fromContainerId cid ++ "] " ++ propertyDesc p
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runningContainer :: ContainerId -> Image -> [RunParam] -> Property
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runningContainer cid@(ContainerId hn cn) image runps = containerDesc cid $ property "running" $ do
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l <- liftIO $ listContainers RunningContainers
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if cid `elem` l
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then do
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-- Check if the ident has changed; if so the
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-- parameters of the container differ and it must
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-- be restarted.
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runningident <- liftIO $ getrunningident
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if runningident == Just ident
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then noChange
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else do
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void $ liftIO $ stopContainer cid
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restartcontainer
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else ifM (liftIO $ elem cid <$> listContainers AllContainers)
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( restartcontainer
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, go image
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)
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where
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ident = ContainerIdent image hn cn runps
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restartcontainer = do
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oldimage <- liftIO $ fromMaybe image <$> commitContainer cid
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void $ liftIO $ removeContainer cid
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go oldimage
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getrunningident :: IO (Maybe ContainerIdent)
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getrunningident = simpleShClient (namedPipe cid) "cat" [propellorIdent] $ \rs -> do
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let !v = extractident rs
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return v
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extractident :: [Resp] -> Maybe ContainerIdent
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extractident = headMaybe . catMaybes . map readish . catMaybes . map getStdout
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go img = do
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liftIO $ do
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clearProvisionedFlag cid
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createDirectoryIfMissing True (takeDirectory $ identFile cid)
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shim <- liftIO $ Shim.setup (localdir </> "propellor") (localdir </> shimdir cid)
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liftIO $ writeFile (identFile cid) (show ident)
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ensureProperty $ boolProperty "run" $ runContainer img
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(runps ++ ["-i", "-d", "-t"])
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[shim, "--docker", fromContainerId cid]
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-- | Called when propellor is running inside a docker container.
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-- The string should be the container's ContainerId.
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--
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-- This process is effectively init inside the container.
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-- It even needs to wait on zombie processes!
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--
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-- Fork a thread to run the SimpleSh server in the background.
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-- In the foreground, run an interactive bash (or sh) shell,
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-- so that the user can interact with it when attached to the container.
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--
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-- When the system reboots, docker restarts the container, and this is run
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-- again. So, to make the necessary services get started on boot, this needs
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-- to provision the container then. However, if the container is already
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-- being provisioned by the calling propellor, it would be redundant and
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-- problimatic to also provisoon it here.
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--
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-- The solution is a flag file. If the flag file exists, then the container
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-- was already provisioned. So, it must be a reboot, and time to provision
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-- again. If the flag file doesn't exist, don't provision here.
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chain :: String -> IO ()
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chain s = case toContainerId s of
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Nothing -> error $ "Invalid ContainerId: " ++ s
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Just cid -> do
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changeWorkingDirectory localdir
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writeFile propellorIdent . show =<< readIdentFile cid
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-- Run boot provisioning before starting simpleSh,
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-- to avoid ever provisioning twice at the same time.
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whenM (checkProvisionedFlag cid) $ do
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let shim = Shim.file (localdir </> "propellor") (localdir </> shimdir cid)
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unlessM (boolSystem shim [Param "--continue", Param $ show $ Chain $ containerHostName cid]) $
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warningMessage "Boot provision failed!"
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void $ async $ job reapzombies
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void $ async $ job $ simpleSh $ namedPipe cid
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job $ do
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void $ tryIO $ ifM (inPath "bash")
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( boolSystem "bash" [Param "-l"]
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, boolSystem "/bin/sh" []
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)
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putStrLn "Container is still running. Press ^P^Q to detach."
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where
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job = forever . void . tryIO
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reapzombies = void $ getAnyProcessStatus True False
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-- | Once a container is running, propellor can be run inside
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-- it to provision it.
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--
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-- Note that there is a race here, between the simplesh
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-- server starting up in the container, and this property
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-- being run. So, retry connections to the client for up to
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-- 1 minute.
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provisionContainer :: ContainerId -> Property
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provisionContainer cid = containerDesc cid $ property "provision" $ liftIO $ do
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let shim = Shim.file (localdir </> "propellor") (localdir </> shimdir cid)
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r <- simpleShClientRetry 60 (namedPipe cid) shim params (go Nothing)
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when (r /= FailedChange) $
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setProvisionedFlag cid
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return r
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where
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params = ["--continue", show $ Chain $ containerHostName cid]
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go lastline (v:rest) = case v of
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StdoutLine s -> do
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maybe noop putStrLn lastline
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hFlush stdout
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go (Just s) rest
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StderrLine s -> do
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maybe noop putStrLn lastline
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hFlush stdout
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hPutStrLn stderr s
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hFlush stderr
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go Nothing rest
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Done -> ret lastline
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go lastline [] = ret lastline
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ret lastline = pure $ fromMaybe FailedChange $ readish =<< lastline
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stopContainer :: ContainerId -> IO Bool
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stopContainer cid = boolSystem dockercmd [Param "stop", Param $ fromContainerId cid ]
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stoppedContainer :: ContainerId -> Property
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stoppedContainer cid = containerDesc cid $ property desc $
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ifM (liftIO $ elem cid <$> listContainers RunningContainers)
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( liftIO cleanup `after` ensureProperty
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(boolProperty desc $ stopContainer cid)
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, return NoChange
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)
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where
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desc = "stopped"
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cleanup = do
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nukeFile $ namedPipe cid
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nukeFile $ identFile cid
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removeDirectoryRecursive $ shimdir cid
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clearProvisionedFlag cid
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removeContainer :: ContainerId -> IO Bool
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removeContainer cid = catchBoolIO $
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snd <$> processTranscript dockercmd ["rm", fromContainerId cid ] Nothing
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removeImage :: Image -> IO Bool
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removeImage image = catchBoolIO $
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snd <$> processTranscript dockercmd ["rmi", image ] Nothing
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runContainer :: Image -> [RunParam] -> [String] -> IO Bool
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runContainer image ps cmd = boolSystem dockercmd $ map Param $
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"run" : (ps ++ image : cmd)
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commitContainer :: ContainerId -> IO (Maybe Image)
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commitContainer cid = catchMaybeIO $
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takeWhile (/= '\n')
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<$> readProcess dockercmd ["commit", fromContainerId cid]
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data ContainerFilter = RunningContainers | AllContainers
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deriving (Eq)
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-- | Only lists propellor managed containers.
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listContainers :: ContainerFilter -> IO [ContainerId]
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listContainers status =
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catMaybes . map toContainerId . concat . map (split ",")
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. catMaybes . map (lastMaybe . words) . lines
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<$> readProcess dockercmd ps
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where
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ps
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| status == AllContainers = baseps ++ ["--all"]
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| otherwise = baseps
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baseps = ["ps", "--no-trunc"]
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listImages :: IO [Image]
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listImages = lines <$> readProcess dockercmd ["images", "--all", "--quiet"]
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runProp :: String -> RunParam -> Property
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runProp field val = pureAttrProperty (param) $ dockerAttr $
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mempty { _dockerRunParams = [\_ -> "--"++param] }
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where
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param = field++"="++val
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genProp :: String -> (HostName -> RunParam) -> Property
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genProp field mkval = pureAttrProperty field $ dockerAttr $
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mempty { _dockerRunParams = [\hn -> "--"++field++"=" ++ mkval hn] }
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dockerAttr :: DockerAttr -> Attr
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dockerAttr a = mempty { _dockerattr = a }
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-- | The ContainerIdent of a container is written to
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-- /.propellor-ident inside it. This can be checked to see if
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-- the container has the same ident later.
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propellorIdent :: FilePath
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propellorIdent = "/.propellor-ident"
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-- | Named pipe used for communication with the container.
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namedPipe :: ContainerId -> FilePath
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namedPipe cid = "docker" </> fromContainerId cid
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provisionedFlag :: ContainerId -> FilePath
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provisionedFlag cid = "docker" </> fromContainerId cid ++ ".provisioned"
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clearProvisionedFlag :: ContainerId -> IO ()
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clearProvisionedFlag = nukeFile . provisionedFlag
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setProvisionedFlag :: ContainerId -> IO ()
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setProvisionedFlag cid = do
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createDirectoryIfMissing True (takeDirectory (provisionedFlag cid))
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writeFile (provisionedFlag cid) "1"
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checkProvisionedFlag :: ContainerId -> IO Bool
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checkProvisionedFlag = doesFileExist . provisionedFlag
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shimdir :: ContainerId -> FilePath
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shimdir cid = "docker" </> fromContainerId cid ++ ".shim"
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identFile :: ContainerId -> FilePath
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identFile cid = "docker" </> fromContainerId cid ++ ".ident"
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readIdentFile :: ContainerId -> IO ContainerIdent
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readIdentFile cid = fromMaybe (error "bad ident in identFile")
|
|
. readish <$> readFile (identFile cid)
|
|
|
|
dockercmd :: String
|
|
dockercmd = "docker.io"
|
|
|
|
report :: [Bool] -> Result
|
|
report rmed
|
|
| or rmed = MadeChange
|
|
| otherwise = NoChange
|
|
|