Add a bunch of new options allowing htsn to daemonize.

[dead/htsn.git] / src / Main.hs

diff --git a/src/Main.hs b/src/Main.hs
index f36e2ba502d743e2d9d9f2665d366df385730a16..b6403614d5d46af193e1f7b2b2adef5ccc8c4bcd 100644 (file)
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -35,7 +35,8 @@ import Configuration ( Configuration(..), merge_optional )
 import ExitCodes (
   exit_no_feed_hosts,
   exit_no_password,
-  exit_no_username )
+  exit_no_username,
+  exit_pidfile_exists )
 import Logging (
   init_logging,
   log_debug,
@@ -53,31 +54,38 @@ import Terminal (
   display_warning )
 import TSN.FeedHosts ( FeedHosts(..) )
 import TSN.Xml ( parse_xmlfid )
+import Unix ( full_daemonize )
 
-
--- | Warning! This does not automatically append a newline. The output
--- is displayed/logged as-is, for, you know, debug purposes.
+-- | Display and log debug information. WARNING! This does not
+--   automatically append a newline. The output is displayed/logged
+--   as-is, for, you know, debug purposes.
 report_debug :: String -> IO ()
 report_debug s = do
   display_debug s
   log_debug s
 
+
+-- | Display and log an error condition. This will prefix the error
+--   with "ERROR: " when displaying (but not logging) it so that it
+--   stands out.
+--
 report_error :: String -> IO ()
 report_error s = do
   display_error $ "ERROR: " ++ s
   log_error s
 
+
+-- | Display and log an informational (status) message.
 report_info :: String -> IO ()
 report_info s = do
   display_info s
   log_info s
 
--- | Warning! This does not automatically append a newline.
-report_sent :: String -> IO ()
-report_sent s = do
-  display_sent s
-  log_debug s
 
+-- | Display and log a warning. This will prefix the warning with
+--   "WARNING: " when displaying (but not logging) it so that it
+--   stands out.
+--
 report_warning :: String -> IO ()
 report_warning s = do
   display_warning $ "WARNING: " ++ s
@@ -103,10 +111,9 @@ recv_line h = do
 --
 save_document :: Configuration -> String -> IO ()
 save_document cfg doc =
-  case maybe_path of
-    Nothing ->
-      report_error "Document missing XML_File_ID element."
-    Just path -> do
+  case either_path of
+    Left err -> report_error err
+    Right path -> do
       already_exists <- doesFileExist path
       when already_exists $ do
         let msg = "File " ++ path ++ " already exists, overwriting."
@@ -114,9 +121,10 @@ save_document cfg doc =
       writeFile path doc
       report_info $ "Wrote file: " ++ path ++ "."
   where
+    -- All the fmaps are because we're working inside a Maybe.
     xmlfid = fmap show (parse_xmlfid doc)
     filename = fmap (++ ".xml") xmlfid
-    maybe_path = fmap ((output_directory cfg) </>) filename
+    either_path = fmap ((output_directory cfg) </>) filename
 
 
 -- | Loop forever, writing the buffer to file whenever a </message>
@@ -175,6 +183,7 @@ log_in cfg h = do
     send_line h' s = do
       let line = s ++ "\r\n"
       hPutStr h' line
+      -- Don't log the username/password!
       display_sent line
 
     recv_chars :: Int -> Handle -> IO String
@@ -266,13 +275,27 @@ main = do
     report_error "No username supplied."
     exitWith (ExitFailure exit_no_username)
 
+  when (daemonize cfg) $ do
+    pidfile_exists <- doesFileExist (pidfile cfg)
+    when pidfile_exists $ do
+      report_error $ "PID file " ++ (pidfile cfg) ++ " already exists. "
+                       ++ "Refusing to start."
+      exitWith (ExitFailure exit_pidfile_exists)
+
   -- This may be superstition (and I believe stderr is unbuffered),
   -- but it can't hurt.
   hSetBuffering stderr NoBuffering
   hSetBuffering stdout NoBuffering
 
-  -- Begin connecting to our feed hosts, starting with the first one.
-  round_robin cfg 0
+  -- The rest of the program is kicked off by the following line which
+  -- begins connecting to our feed hosts, starting with the first one,
+  -- and proceeds in a round-robin fashion.
+  let run_program = round_robin cfg 0
+
+  -- If we were asked to daemonize, do that; otherwise just run the thing.
+  if (daemonize cfg)
+  then full_daemonize cfg run_program
+  else run_program
 
   where
     -- | This is the top-level "loop forever" function. If an