Reorganize + implement dm workdir resolution

1. *.Types are not exposed, just re-exported from *.Parser
2. Removed Locator since its logic was mostly depended on Config.Parser

dockmaster.cabal

@@ -20,11 +20,10 @@ description:
 library
   hs-source-dirs:      src
   exposed-modules:     Dockmaster
-                     , Dockmaster.Types
-                     , Dockmaster.Config.Types
-  other-modules:       Dockmaster.Locator
                      , Dockmaster.Parser
                      , Dockmaster.Config.Parser
+  other-modules:       Dockmaster.Types
+                     , Dockmaster.Config.Types
                      , Dockmaster.Utils
   build-depends:       base >= 4.7 && < 5
                      , yaml
@@ -34,6 +33,7 @@ library
                      , text
                      , bytestring
                      , regex-posix
+                     , system-filepath >= 0.4.7 && < 0.5
   default-language:    Haskell2010
 
 executable dm

src/Dockmaster.hs

@@ -5,14 +5,14 @@ module Dockmaster
   ( dm
   ) where
 
+-- Base modules
 import Data.Either
 import Data.Monoid ((<>))
 import Data.Maybe
 
 -- Local modules
-import Dockmaster.Locator
 import Dockmaster.Parser
-import Dockmaster.Types
+import Dockmaster.Config.Parser
 
 -- External modules
 import Shelly
@@ -27,6 +27,7 @@ type DCCommand = T.Text
 -- See usage docs for more info. Tries to find a dockmaster.yml file based on
 -- the initial path argument
 -- TODO monad >>= and >> the shit out of this to remove the casing structure
+-- TODO Possibly remove Either return types & just error out whenever
 -- REMEMBER you can do `when weAreDone exitSuccess` as control flow in do statement
 dm :: FilePath -> DCCommand -> [T.Text] -> Sh ()
 dm path command args = do

src/Dockmaster/Config/Parser.hs

@@ -2,8 +2,17 @@
 {-# LANGUAGE ExtendedDefaultRules #-}
 {-# OPTIONS_GHC -fno-warn-type-defaults #-}
 module Dockmaster.Config.Parser
-  ( config
+  (
+  -- * Getting global config
+    config
   , baseConfig
+
+  -- * Resolving relative paths
+  , getWorkDir
+  , getWorkDir'
+
+  -- * Re-exported for convenience
+  , module Dockmaster.Config.Types
   ) where
 
 -- Local modules
@@ -16,13 +25,15 @@ import qualified Data.ByteString as BS
 import Shelly
 import Prelude hiding (FilePath)
 import qualified Data.Text as T
+import qualified Filesystem.Path.CurrentOS as FP
 import Data.Monoid ((<>), mconcat, First(..))
 import Control.Monad (liftM)
 default (T.Text)
 
 -- | Get global dockmaster config
--- If config.yml fails to parse, returns Left error
--- If config.yml is not found, returns Right baseConfig (default configuration)
+--
+-- If config.yml fails to parse, returns Left error.
+-- If config.yml is not found, returns Right baseConfig (default configuration).
 config :: Sh (Either T.Text Config)
 config = do
   mPath <- resolvePath
@@ -33,10 +44,15 @@ config = do
       return $
         eitherWrap T.pack id (decodeEither contents :: Either String Config)
 
+-- | Get base config options
+baseConfig :: Config
+baseConfig = Config { dmcPaths = [] }
+
 -- | Resolves path to dockmaster config.yml in the following order of precedence:
--- - DOCKMASTER_CONFIG environment variable
--- - $HOME/.dockmaster/config.yml
--- - /etc/dockmaster/config.yml
+--
+--     (1) DOCKMASTER_CONFIG environment variable
+--     (2) $HOME/.dockmaster/config.yml
+--     (3) /etc/dockmaster/config.yml
 resolvePath :: Sh (Maybe FilePath)
 resolvePath = do
   envPathT  <- get_env "DOCKMASTER_CONFIG"
@@ -45,6 +61,50 @@ resolvePath = do
   return $
     getFirst . mconcat $ map First [envPathT >>= (return . fromText), homePath, etcPath]
 
--- | Get base config options
-baseConfig :: Config
-baseConfig = Config { dmcPaths = [] }
+-- | Resolve the appropriate dockmaster workdir.
+--
+-- For example, if @$CWD/dockmaster.yml@ exists, then
+-- >>> getWorkDir "."
+-- Right "."
+--
+-- If @$CWD/dockmaster.yml@ does /not/ exist, then
+-- >>> getWorkDir "."
+-- Left "dockmaster.yml file not found"
+--
+-- This function will also try to resolve relative paths against the 'dmcPath'
+-- composition listing directories, if any are specified by global config.
+-- For example, if:
+--
+--   (1) @$HOME/git@ is a PATH specified in global config.yml
+--   (2) @$HOME/git/deploybot/dockmaster.yml@ exists
+--   (3) @$CWD/deploybot/dockmaster.yml@ does /not/ exist, then
+-- >>> getWorkDir "deploybot"
+-- Right "$HOME/git/deploybot"
+getWorkDir :: FilePath -> Sh (Either T.Text FilePath)
+getWorkDir p = undefined
+
+-- | Same thing as 'getWorkDir' but uses a 'Config' argument instead of
+-- resolving one.
+getWorkDir' :: Config -> FilePath -> Sh (Either T.Text FilePath)
+getWorkDir' cfg p = do
+  -- If absolute path is given, it is the only one attempted
+  mPath <- getFirst <$> if FP.absolute p
+              then tryPath p
+              else mconcat <$> mapM tryPath (map (</> p) $ "." : dmcPaths cfg)
+
+  return $ maybe workDirNotFound Right mPath
+
+-- | Check if directory @dir@ contains a @dockmaster.yml@ file
+-- If it does, return @First dir@, otherwise Nothing
+-- Using the @First@ monoid so we can have precedence for composition listings
+tryPath :: FilePath -> Sh (First FilePath)
+tryPath dir = do
+  found <- test_e (dir </> "dockmaster.yml")
+  return . First $ if found
+     then Just dir
+     else Nothing
+
+
+-- | Just a small abstraction to keep error message on its own
+workDirNotFound :: Either T.Text b
+workDirNotFound = Left "dockmaster.yml file not found"

src/Dockmaster/Parser.hs

@@ -2,12 +2,14 @@
 {-# LANGUAGE ExtendedDefaultRules #-}
 {-# OPTIONS_GHC -fno-warn-type-defaults #-}
 module Dockmaster.Parser
-  (
-  dockmasterYml
+  ( dockmasterYml
+  -- * Re-exported for convenience
+  , module Dockmaster.Types
   ) where
 
 -- Local modules
 import Dockmaster.Utils (eitherWrap)
+import Dockmaster.Config.Parser
 
 -- External modules
 import Data.Yaml
@@ -19,6 +21,9 @@ import Prelude hiding (FilePath)
 import qualified Data.Text as T
 default (T.Text)
 
+-- | Parse $CWD/dockmaster.yml
+--
+-- Note this assumes we are already in the correct dockmaster workdir
 dockmasterYml :: Sh (Either T.Text Dockmaster)
 dockmasterYml = do
   contents <- readBinary "dockmaster.yml"

test/Spec.hs

@@ -1,12 +1,14 @@
 module Main where
 
 import Data.Yaml
-import Dockmaster.Types
+import Dockmaster.Parser
 import qualified Data.ByteString as BS
 import Data.Maybe
 import System.Exit
 import System.Directory
 
+-- TODO test Dockmaster.Parser.dockmasterYml instead of using this parse function
+
 parseDockmasterYml :: FilePath -> IO Bool
 parseDockmasterYml "."  = return True
 parseDockmasterYml ".." = return True