feat(dinghy): add ability to write dinghyfiles

package.yaml

@@ -13,13 +13,16 @@ extra-source-files:
 
 dependencies:
   - base >= 4.7 && < 5
-  - text
-  - yaml
   - aeson
+  - aeson-pretty
+  - bytestring
   - directory
-  - unordered-containers
+  - filepath
   - hashable
   - optparse-applicative
+  - text
+  - unordered-containers
+  - yaml
 
 ghc-options:
   - -Wall

src/Dinghy.hs

@@ -11,12 +11,17 @@ Stability   : experimental
 
 module Dinghy where
 
+import qualified Data.Text as T
+import qualified Data.Aeson.Encode.Pretty as Json
 import Data.Aeson         (ToJSON (toEncoding), Value, defaultOptions,
                            fieldLabelModifier, genericToEncoding,
                            omitNothingFields)
 import Data.Text          (Text)
 import Dinghy.Application
 import GHC.Generics       (Generic)
+import qualified System.Directory as Dir
+import System.FilePath.Posix ((</>))
+import qualified Data.ByteString.Lazy as BS
 
 -- | Subset of the Dinghyfile spec.
 --
@@ -32,6 +37,15 @@ data Dinghyfile = Dinghyfile {
 instance ToJSON Dinghyfile where
   toEncoding = genericToEncoding $ defaultOptions { omitNothingFields = True }
 
+writeDinghyfile :: Text -> Dinghyfile -> IO ()
+writeDinghyfile outputPath dinghyfile = do
+  _ <- Dir.createDirectory dir
+  BS.writeFile fname $ Json.encodePretty dinghyfile
+    where
+      name = T.unpack $ application dinghyfile
+      dir = (T.unpack outputPath) </> name
+      fname = dir </> "Dinghyfile"
+
 -- | Subset of a Pipeline representation in Dinghy.
 --
 -- TODO

src/Main.hs

@@ -5,18 +5,20 @@ module Main where
 import           Cli              (Command (..), inputPath, outputPath)
 import qualified Cli
 import           Control.Monad    (join)
+import Data.Foldable (traverse_)
 import qualified Data.Text        as T
 import qualified Migrate
 import           Pacrd
+import qualified Dinghy
 import qualified System.Directory as Dir
 import           Wrapper
 
 main :: IO ()
 main = do
+    -- TODO consider adding logging here
     Command { inputPath, outputPath } <- Cli.parseCli
     files <- filter isYamlFile <$> Dir.listDirectory (T.unpack inputPath)
     manifests <- join <$> mapM readManifest files
     let (apps, pipes) = splitWrapper manifests
-    print . Migrate.convertPacrdTree $ pacrdTree apps pipes
-    -- TODO
-    putStrLn $ "Writing Dinghyfile to ... '" <> T.unpack outputPath <> "'"
+    (flip traverse_) (Migrate.convertPacrdTree $ pacrdTree apps pipes) $ \d ->
+      Dinghy.writeDinghyfile outputPath d