Logging: export logMessagesToJSON.

Use a deterministic order for fields.

2 files changed, 12 insertions, 2 deletions

diff --git a/src/Text/Pandoc/App.hs b/src/Text/Pandoc/App.hs
index df1ed9fde..e4e47c1bf 100644
--- a/src/Text/Pandoc/App.hs
+++ b/src/Text/Pandoc/App.hs
@@ -71,12 +71,12 @@ import qualified Data.ByteString.Lazy as B
 import qualified Data.ByteString as BS
 import qualified Data.Map as M
 import Data.Aeson (eitherDecode', encode)
-import Data.Aeson.Encode.Pretty (encodePretty)
 import Data.Yaml (decode)
 import qualified Data.Yaml as Yaml
 import qualified Data.Text as T
 import System.Console.GetOpt
 import Text.Pandoc.Class (withMediaBag, PandocIO, getLog)
+import Text.Pandoc.Logging (logMessagesToJSON)
 import Paths_pandoc (getDataDir)
 #ifndef _WINDOWS
 import System.Posix.Terminal (queryTerminal)
@@ -351,7 +351,7 @@ convertWithOpts opts = do
                              return (x, rs)
         case optLogFile opts of
              Nothing -> return ()
-             Just logfile -> B.writeFile logfile (encodePretty reports)
+             Just logfile -> B.writeFile logfile (logMessagesToJSON reports)
         let isWarning msg = messageVerbosity msg == WARNING
         when (optFailIfWarnings opts && any isWarning reports) $
             err 3 "Failing because there were warnings."
diff --git a/src/Text/Pandoc/Logging.hs b/src/Text/Pandoc/Logging.hs
index 8b2b85a45..15b903c05 100644
--- a/src/Text/Pandoc/Logging.hs
+++ b/src/Text/Pandoc/Logging.hs
@@ -32,6 +32,7 @@ and info messages.
 module Text.Pandoc.Logging (
     Verbosity(..)
   , LogMessage(..)
+  , logMessagesToJSON
   , showLogMessage
   , messageVerbosity
   ) where
@@ -43,6 +44,9 @@ import GHC.Generics (Generic)
 import qualified Data.Text as Text
 import Data.Aeson
 import Text.Pandoc.Definition
+import Data.Aeson.Encode.Pretty (encodePretty', keyOrder,
+                                 defConfig, Config(..))
+import qualified Data.ByteString.Lazy as BL
 
 -- | Verbosity level.
 data Verbosity = ERROR | WARNING | INFO | DEBUG
@@ -152,6 +156,12 @@ showPos pos = sn ++ "line " ++
                 then ""
                 else sourceName pos ++ " "
 
+logMessagesToJSON :: [LogMessage] -> BL.ByteString
+logMessagesToJSON ms =
+  encodePretty' defConfig{ confCompare =
+      keyOrder [ "type", "verbosity", "contents", "message", "path",
+                 "source", "line", "column" ] } ms
+
 showLogMessage :: LogMessage -> String
 showLogMessage msg =
   case msg of