src/Main.hs

   1 {-# LANGUAGE DoAndIfThenElse #-}
   2 {-# LANGUAGE NoMonomorphismRestriction #-}
   3 module Main
   4 where
   5
   6 -- System imports.
   7 import Control.Arrow ( (&&&), (>>^), arr, returnA )
   8 import Control.Concurrent ( threadDelay )
   9 import Control.Exception ( SomeException, catch )
  10 import Control.Monad ( when )
  11 import Database.Groundhog.Generic ( runDbConn )
  12 import Database.Groundhog.Sqlite (
  13   withSqliteConn )
  14 import Database.Groundhog.Postgresql (
  15   withPostgresqlConn )
  16 import Data.Monoid ( (<>) )
  17 import Network.Services.TSN.Logging ( init_logging )
  18 import System.Console.CmdArgs ( def )
  19 import System.Directory ( removeFile )
  20 import System.Exit ( exitWith, ExitCode (ExitFailure) )
  21 import System.IO.Error ( catchIOError )
  22 import Text.XML.HXT.Core (
  23   ArrowXml,
  24   IOStateArrow,
  25   SysConfigList,
  26   XmlTree,
  27   (>>>),
  28   (/>),
  29   getAttrl,
  30   getText,
  31   hasName,
  32   readDocument,
  33   runX,
  34   unpickleDoc )
  35
  36 -- Local imports.
  37 import Backend ( Backend(..) )
  38 import CommandLine ( get_args )
  39 import Configuration ( Configuration(..), merge_optional )
  40 import ConnectionString ( ConnectionString(..) )
  41 import ExitCodes ( exit_no_xml_files )
  42 import qualified OptionalConfiguration as OC (
  43   OptionalConfiguration ( xml_files ),
  44   from_rc )
  45 import Network.Services.TSN.Report (
  46   report_info,
  47   report_error )
  48 import TSN.DbImport ( DbImport(..), ImportResult(..) )
  49 import TSN.Parse ( format_parse_error )
  50 import qualified TSN.XML.AutoRacingDriverList as AutoRacingDriverList (
  51   dtd,
  52   pickle_message )
  53 import qualified TSN.XML.AutoRacingResults as AutoRacingResults (
  54   dtd,
  55   pickle_message )
  56 import qualified TSN.XML.AutoRacingSchedule as AutoRacingSchedule (
  57   dtd,
  58   pickle_message )
  59 import qualified TSN.XML.EarlyLine as EarlyLine (
  60   dtd,
  61   pickle_message )
  62 import qualified TSN.XML.GameInfo as GameInfo ( dtds, parse_xml )
  63 import qualified TSN.XML.Heartbeat as Heartbeat ( dtd, verify )
  64 import qualified TSN.XML.Injuries as Injuries ( dtd, pickle_message )
  65 import qualified TSN.XML.InjuriesDetail as InjuriesDetail (
  66   dtd,
  67   pickle_message )
  68 import qualified TSN.XML.MLBEarlyLine as MLBEarlyLine (
  69   dtd,
  70   pickle_message )
  71 import qualified TSN.XML.JFile as JFile ( dtd, pickle_message )
  72 import qualified TSN.XML.News as News (
  73   dtd,
  74   has_only_single_sms,
  75   pickle_message )
  76 import qualified TSN.XML.Odds as Odds ( dtd, pickle_message )
  77 import qualified TSN.XML.ScheduleChanges as ScheduleChanges (
  78   dtd,
  79   pickle_message )
  80 import qualified TSN.XML.Scores as Scores ( dtd, pickle_message )
  81 import qualified TSN.XML.SportInfo as SportInfo ( dtds, parse_xml )
  82 import qualified TSN.XML.Weather as Weather (
  83   dtd,
  84   is_type1,
  85   pickle_message,
  86   teams_are_normal )
  87 import Xml ( DtdName(..), parse_opts, parse_opts_novalidate )
  88
  89
  90 -- | This is where most of the work happens. This function is called
  91 --   on every file that we would like to import. It determines which
  92 --   importer to use based on the DTD, attempts to process the file,
  93 --   and then returns whether or not it was successful. If the file
  94 --   was processed, 'True' is returned. Otherwise, 'False' is
  95 --   returned.
  96 --
  97 --   The implementation is straightforward with one exception: since
  98 --   we are already in arrow world with HXT, the @import_with_dtd@
  99 --   function is lifted to an 'Arrow' as well with 'arr'. This
 100 --   prevents us from having to do a bunch of unwrapping and
 101 --   rewrapping with the associated error checking.
 102 --
 103 import_file :: Configuration -- ^ A configuration object needed for the
 104                              --   'backend' and 'connection_string'.
 105
 106             -> FilePath -- ^ The path of the XML file to import.
 107
 108             -> IO Bool -- ^ True if we processed the file, False otherwise.
 109 import_file cfg path = do
 110   results <- parse_and_import `catch` exception_handler
 111   case results of
 112     []    -> do
 113       -- One of the arrows returned "nothing."  Now that we're
 114       -- validating against the DTDs, this will almost always be
 115       -- caused by a document whose DTD is not present (i.e. is
 116       -- unsupported). So we return "success" to allow the XML file to
 117       -- be deleted.
 118       report_info $ "No DTD for file " ++ path ++ "."
 119       return True
 120     (ImportFailed errmsg:_) -> do
 121       report_error $ errmsg ++ " (" ++ path ++ ")"
 122       return False
 123     (ImportSkipped infomsg:_) -> do
 124       -- We processed the message but didn't import anything. Return
 125       -- "success" so that the XML file is deleted.
 126       report_info infomsg
 127       return True
 128     (ImportSucceeded:_) -> do
 129       report_info $ "Successfully imported " ++ path ++ "."
 130       return True
 131     (ImportUnsupported infomsg:_) -> do
 132       -- For now we return "success" for these too, since we know we don't
 133       -- support a bunch of DTDs and we want them to get deleted.
 134       report_info infomsg
 135       return True
 136   where
 137     -- | This will catch *any* exception, even the ones thrown by
 138     --   Haskell's 'error' (which should never occur under normal
 139     --   circumstances).
 140     exception_handler :: SomeException -> IO [ImportResult]
 141     exception_handler e = do
 142       report_error (show e)
 143       let errdesc = "Failed to import file " ++ path ++ "."
 144       -- Return a nonempty list so we don't claim incorrectly that
 145       -- we couldn't parse the DTD.
 146       return [ImportFailed errdesc]
 147
 148     -- | An arrow that reads a document into an 'XmlTree'.  We take a
 149     --   SysConfigList so our caller can decide whether or not to
 150     --   e.g. validate the document against its DTD.
 151     readA :: SysConfigList -> IOStateArrow s a XmlTree
 152     readA scl = readDocument scl path
 153
 154     -- | An arrow which parses the doctype "SYSTEM" of an 'XmlTree'.
 155     --   We use these to determine the parser to use.
 156     dtdnameA :: ArrowXml a => a XmlTree DtdName
 157     dtdnameA = getAttrl >>> hasName "doctype-SYSTEM" /> getText >>^ DtdName
 158
 159     -- | Combine the arrows above as well as the function below
 160     --   (arrowized with 'arr') into an IO action that does everything
 161     --   (parses and then runs the import on what was parsed).
 162     --
 163     --   The result of runX has type IO [IO ImportResult]. We thus use
 164     --   bind (>>=) and sequence to combine all of the IOs into one
 165     --   big one outside of the list.
 166     --
 167     --   Before we actually run the import, we check it against a list
 168     --   of problem DTDs. These can produce weird errors, and we have
 169     --   checks for them. But with DTD validation enabled, we can't
 170     --   even look inside the document to see what's wrong -- parsing
 171     --   will fail! So for those special document types, we proceed
 172     --   using 'parse_opts_novalidate' instead of the default
 173     --   'parse_opts'.
 174     --
 175     parse_and_import :: IO [ImportResult]
 176     parse_and_import = do
 177       -- Get the DTD name without validating against it.
 178       ((DtdName dtd) : _) <- runX $ (readA parse_opts_novalidate) >>> dtdnameA
 179
 180       let problem_dtds = [ News.dtd, Weather.dtd ]
 181       let opts = if dtd `elem` problem_dtds
 182                  then parse_opts_novalidate
 183                  else parse_opts
 184
 185       runX ((readA opts) >>> (dtdnameA &&& returnA) >>> (arr import_with_dtd))
 186         >>= sequence
 187
 188     -- | Takes a ('DtdName', 'XmlTree') pair and uses the 'DtdName'
 189     --   to determine which function to call on the 'XmlTree'.
 190     import_with_dtd :: (DtdName, XmlTree) -> IO ImportResult
 191     import_with_dtd (DtdName dtd,xml)
 192         -- We special-case the heartbeat so it doesn't have to run in
 193         -- the database monad.
 194       | dtd == Heartbeat.dtd = Heartbeat.verify xml
 195       | otherwise =
 196         -- We need NoMonomorphismRestriction here.
 197         if backend cfg == Postgres
 198         then withPostgresqlConn cs $ runDbConn importer
 199         else withSqliteConn cs $ runDbConn importer
 200         where
 201           -- | Pull the real connection String out  of the configuration.
 202           --
 203           cs :: String
 204           cs = get_connection_string $ connection_string cfg
 205
 206           -- | Convenience; we use this everywhere below in 'importer'.
 207           --
 208           migrate_and_import m = dbmigrate m >> dbimport m
 209
 210           -- | The error message we return if unpickling fails.
 211           --
 212           errmsg = "Could not unpickle " ++ dtd ++ "."
 213
 214           -- | Try to migrate and import using the given pickler @f@;
 215           --   if it works, return the result. Otherwise, return an
 216           --   'ImportFailed' along with our error message.
 217           --
 218           go f = maybe
 219                    (return $ ImportFailed errmsg)
 220                    migrate_and_import
 221                    (unpickleDoc f xml)
 222
 223           importer
 224             | dtd == AutoRacingDriverList.dtd =
 225                 go AutoRacingDriverList.pickle_message
 226
 227             | dtd == AutoRacingResults.dtd =
 228                 go AutoRacingResults.pickle_message
 229
 230             | dtd == AutoRacingSchedule.dtd =
 231                 go AutoRacingSchedule.pickle_message
 232
 233             | dtd == EarlyLine.dtd =
 234                 go EarlyLine.pickle_message
 235
 236             -- GameInfo and SportInfo appear last in the guards
 237             | dtd == Injuries.dtd = go Injuries.pickle_message
 238
 239             | dtd == InjuriesDetail.dtd = go InjuriesDetail.pickle_message
 240
 241             | dtd == JFile.dtd = go JFile.pickle_message
 242
 243             | dtd == MLBEarlyLine.dtd = go MLBEarlyLine.pickle_message
 244
 245             | dtd == News.dtd =
 246                 -- Some of the newsxml docs are busted in predictable ways.
 247                 -- We want them to "succeed" so that they're deleted.
 248                 -- We already know we can't parse them.
 249                 if News.has_only_single_sms xml
 250                 then go News.pickle_message
 251                 else do
 252                   let msg = "Unsupported newsxml.dtd with multiple SMS " ++
 253                             "(" ++ path ++ ")"
 254                   return $ ImportUnsupported msg
 255             | dtd == Odds.dtd = go Odds.pickle_message
 256
 257             | dtd == ScheduleChanges.dtd = go ScheduleChanges.pickle_message
 258
 259             | dtd == Scores.dtd = go Scores.pickle_message
 260
 261             -- SportInfo and GameInfo appear last in the guards
 262             | dtd == Weather.dtd =
 263                 -- Some of the weatherxml docs are busted in predictable ways.
 264                 -- We want them to "succeed" so that they're deleted.
 265                 -- We already know we can't parse them.
 266                 if Weather.is_type1 xml
 267                 then if Weather.teams_are_normal xml
 268                      then go Weather.pickle_message
 269                      else do
 270                        let msg = "Teams in reverse order in weatherxml.dtd" ++
 271                                  " (" ++ path ++ ")"
 272                        return $ ImportUnsupported msg
 273                 else do
 274                   let msg = "Unsupported weatherxml.dtd type (" ++ path ++ ")"
 275                   return $ ImportUnsupported msg
 276
 277             | dtd `elem` GameInfo.dtds = do
 278                 let either_m = GameInfo.parse_xml dtd xml
 279                 case either_m of
 280                   -- This might give us a slightly better error
 281                   -- message than the default 'errmsg'.
 282                   Left err -> return $ ImportFailed (format_parse_error err)
 283                   Right m     -> migrate_and_import m
 284
 285             | dtd `elem` SportInfo.dtds = do
 286                 let either_m = SportInfo.parse_xml dtd xml
 287                 case either_m of
 288                   -- This might give us a slightly better error
 289                   -- message than the default 'errmsg'.
 290                   Left err -> return $ ImportFailed (format_parse_error err)
 291                   Right m     -> migrate_and_import m
 292
 293             | otherwise = do
 294               let infomsg =
 295                     "Unrecognized DTD in " ++ path ++ ": " ++ dtd ++ "."
 296               -- This should be an impossible case while DTD
 297               -- validation is enabled. If we can parse the file at
 298               -- all, then we have a DTD for it sitting around. And we
 299               -- only have DTDs for supported types.
 300               return $ ImportUnsupported infomsg
 301
 302
 303
 304 -- | Entry point of the program. It twiddles some knobs for
 305 --   configuration options and then calls 'import_file' on each XML
 306 --   file given on the command-line.
 307 --
 308 --   Any file successfully processed is then optionally removed, and
 309 --   we're done.
 310 --
 311 main :: IO ()
 312 main = do
 313   rc_cfg <- OC.from_rc
 314   cmd_cfg <- get_args
 315
 316   -- Merge the config file options with the command-line ones,
 317   -- prefering the command-line ones.
 318   let opt_config = rc_cfg <> cmd_cfg
 319
 320   -- Update a default config with any options that have been set in
 321   -- either the config file or on the command-line.  We initialize
 322   -- logging before the missing parameter checks below so that we can
 323   -- log the errors.
 324   let cfg = (def :: Configuration) `merge_optional` opt_config
 325   init_logging (log_level cfg) (log_file cfg) (syslog cfg)
 326
 327   -- Check the optional config for missing required options.
 328   when (null $ OC.xml_files opt_config) $ do
 329     report_error "No XML files given."
 330     exitWith (ExitFailure exit_no_xml_files)
 331
 332   -- We don't do this in parallel (for now?) to keep the error
 333   -- messages nice and linear.
 334   results <- mapM (import_file cfg) (OC.xml_files opt_config)
 335
 336   -- Zip the results with the files list to find out which ones can be
 337   -- deleted.
 338   let result_pairs = zip (OC.xml_files opt_config) results
 339   let victims = [ p | (p, True) <- result_pairs ]
 340   let processed_count = length victims
 341   report_info $ "Processed " ++ (show processed_count) ++ " document(s) total."
 342   when (remove cfg) $ mapM_ (kill True) victims
 343
 344   where
 345     -- | Wrap these two actions into one function so that we don't
 346     --   report that the file was removed if the exception handler is
 347     --   run.
 348     remove_and_report path = do
 349       removeFile path
 350       report_info $ "Removed processed file " ++ path ++ "."
 351
 352     -- | Try to remove @path@ and potentially try again.
 353     kill try_again path =
 354       (remove_and_report path) `catchIOError` exception_handler
 355       where
 356         -- | A wrapper around threadDelay which takes seconds instead of
 357         --   microseconds as its argument.
 358         thread_sleep :: Int -> IO ()
 359         thread_sleep seconds = do
 360           let microseconds = seconds * (10 ^ (6 :: Int))
 361           threadDelay microseconds
 362
 363         -- | If we can't remove the file, report that, and try once
 364         --   more after waiting a few seconds.
 365         exception_handler :: IOError -> IO ()
 366         exception_handler e = do
 367           report_error (show e)
 368           report_error $ "Failed to remove imported file " ++ path ++ "."
 369           if try_again then do
 370             report_info "Waiting 5 seconds to attempt removal again..."
 371             thread_sleep 5
 372             kill False path
 373           else
 374             report_info $ "Giving up on " ++ path ++ "."