Adds redirect-lilypond-output option to lilypond-book (issue4664060)

[PhilEHolmes]

Reviewers: Graham Percival,

Message:
Please review the patch set to add the redirect option.

Description:
Adds a new option to lilypond-book that causes the lilypond
output to be directed to logfiles.  The option is:
--redirect-lilypond-output.

This is a possible pre-cursor to further build work, but
only possible.

Test cases and further information at:
http://www.holmessoft.co.uk/homepage/private/lilypond/

Please review this at http://codereview.appspot.com/4664060/

Affected files:
  M python/lilylib.py
  M scripts/lilypond-book.py


Index: python/lilylib.py
diff --git a/python/lilylib.py b/python/lilylib.py
index  
dac53c16cf4dd5d83c2111e4ba49e28701f410b0..06bb5c361b835a78779c2bb1038c2b033cea99e2  
100644
--- a/python/lilylib.py
+++ b/python/lilylib.py
@@ -23,6 +23,7 @@ import re
 import shutil
 import sys
 import optparse
+import time

 ################################################################
 # Users of python modules should include this snippet
@@ -118,6 +119,7 @@ def subprocess_system (cmd,
                        ignore_error=False,
                        progress_p=True,
                        be_verbose=False,
+                       redirect_output=False,
                        log_file=None):
     import subprocess

@@ -125,34 +127,52 @@ def subprocess_system (cmd,
     name = command_name (cmd)
     error_log_file = ''

-    if be_verbose:
-       show_progress = 1
-       progress (_ ("Invoking `%s\'") % cmd)
+    if redirect_output:
+        progress (_ ("Processing %s.ly") % log_file)
+        progress ('\n')
     else:
-       progress ( _("Running %s...") % name)
-
+        if be_verbose:
+            show_progress = 1
+            progress (_ ("Invoking `%s\'") % cmd)
+        else:
+            progress ( _("Running %s...") % name)

     stdout_setting = None
+    stderr_setting = None
     if not show_progress:
-       stdout_setting = subprocess.PIPE
+        stdout_setting = subprocess.PIPE
+
+    if redirect_output:
+        stdout_filename = ''.join([log_file, '.log'])
+        stderr_filename = ''.join([log_file, '.err.log'])
+        stdout_setting = open(stdout_filename, 'w')
+        stderr_setting = open(stderr_filename, 'w')

     proc = subprocess.Popen (cmd,
                              shell=True,
                              universal_newlines=True,
                              stdout=stdout_setting,
-                             stderr=stdout_setting)
+                             stderr=stderr_setting)

     log = ''

-    if show_progress:
-       retval = proc.wait()
+    if redirect_output:
+        while proc.poll()==None:
+            time.sleep(1)
+        retval = proc.returncode
+        stdout_setting.close()
+        stderr_setting.close()
     else:
-       log = proc.communicate ()
-       retval = proc.returncode
-
+        if show_progress:
+            retval = proc.wait()
+        else:
+            log = proc.communicate ()
+            retval = proc.returncode

     if retval:
         print >>sys.stderr, 'command failed:', cmd
+        if redirect_output:
+            print >>sys.stderr, "Look in logfile", stderr_filename
         if retval < 0:
             print >>sys.stderr, "Child was terminated by signal", -retval
         elif retval > 0:
Index: scripts/lilypond-book.py
diff --git a/scripts/lilypond-book.py b/scripts/lilypond-book.py
index  
9617f3666d3a4c878325a089b3d898def9771a8d..cb3ff4de3269861c09f0e5d83bb46a2bbdd39ca4  
100644
--- a/scripts/lilypond-book.py
+++ b/scripts/lilypond-book.py
@@ -179,6 +179,11 @@ def get_option_parser ():
                   action='store',
                   dest='process_cmd', default='')

+    p.add_option ('--redirect-lilypond-output',
+                  help = _ ("Redirect the lilypond output"),
+                  action='store_true',
+                  dest='redirect_output', default=False)
+
     p.add_option ('-s', '--safe', help=_ ("Compile snippets in safe mode"),
                   action="store_true",
                   default=False,
@@ -347,7 +352,7 @@ def find_toplevel_snippets (input_string, formatter):

     return snippets

-def system_in_directory (cmd, directory):
+def system_in_directory (cmd, directory, logfile):
     """Execute a command in a different directory.

     Because of win32 compatibility, we can't simply use subprocess.
@@ -355,7 +360,10 @@ def system_in_directory (cmd, directory):

     current = os.getcwd()
     os.chdir (directory)
-    ly.system(cmd, be_verbose=global_options.verbose,
+    ly.system(cmd,
+              be_verbose=global_options.verbose,
+              redirect_output=global_options.redirect_output,
+              log_file=logfile,
               progress_p=1)
     os.chdir (current)

@@ -374,11 +382,12 @@ def process_snippets (cmd, snippets,
                           + list (set ([snip.basename() + '.ly' for snip  
in snippets])))
     name = os.path.join (lily_output_dir,
                          'snippet-names-%d.ly' % checksum)
+    logfile = name.replace('.ly', '')
     file (name, 'wb').write (contents)

     system_in_directory (' '.join ([cmd, ly.mkarg (name)]),
-                         lily_output_dir)
-
+                         lily_output_dir,
+                         logfile)

 def snippet_list_checksum (snippets):
     return hash (' '.join([l.basename() for l in snippets]))