[file_utils] dirpacker: rework message printing

file_utils/dirpacker.py

@@ -33,6 +33,7 @@
 import argparse
 import os
 import shutil
+import sys
 from collections import defaultdict
 import math
 
@@ -52,12 +53,12 @@ class Bin:
     def print(self):
         """Displays the contents of the bin.
         """
-        print("\n### {} ###\n# List of files:".format(self.name()))
+        print("\n### {} ###\nList of files:".format(self.name()))
         for filename, size in sorted(self.files.items()):
-            print("{} # {:.2f} MiB".format(filename, size))
-        print("# This bin's size: {:.2f} MiB".format(self.size))
+            print("{:12.2f} MiB\t{}".format(size, filename))
         sizefree = options.maxbinsize - self.size
-        print("# Free space: {:.2f} MiB".format(sizefree))
+        print("This bin's size: {:.2f} MiB".format(self.size))
+        print("Unused: {:.2f} MiB".format(sizefree))
 
     def name(self):
         """Returns the bin's name'
@@ -70,6 +71,19 @@ class Bin:
         return list(self.files.keys())
 
 
+def warn(*message, prefix="Warning!", **args):
+    """Prints the message on the error output, prepended by 'prefix'.
+
+    The standard output is flushed prior to printing the error message, to
+    enable the messages to be displayed in the right order.
+
+    This function is a simple wrapper around print(), and you can use any
+    keyword argument you would use with print().
+    """
+    sys.stdout.flush()
+    print(prefix, *message, file=sys.stderr, **args)
+
+
 def du(basepath):
     """ Returns the size of the file of directory `basepath`, in MiB.
     """
@@ -134,7 +148,7 @@ options = arg_parser.parse_args()
 ### Preliminary statistics ###
 
 if options.verbose:
-    print("# Maximum size of a bin: {:.2f} MiB".format(options.maxbinsize))
+    print("Maximum size of a bin: {:.2f} MiB".format(options.maxbinsize))
 
 # Compute the size of all the files
 sizes = defaultdict(list)
@@ -143,20 +157,20 @@ ignored_files = False
 for filename in options.filenames:
     size = du(filename)
     if (size > options.maxbinsize):
-        print('# WARNING! "{}" is {:.2f} MiB, which exceeds the maximum size of'
-              ' a bin: ignoring.'
-              .format(filename, size))
+        warn('"{}" is {:.2f} MiB, which exceeds the maximum size of a bin:'
+             ' ignoring.'
+             .format(filename, size))
         ignored_files = True
         continue
     sizes[size].append(filename)
     totalsize += size
 
 if options.verbose:
-    print("# Total size of the input files: {:.2f} MiB".format(totalsize))
+    print("Total size of the input files: {:.2f} MiB".format(totalsize))
     minbins = math.ceil(totalsize / options.maxbinsize)
-    print("# Minimal (optimal) number of bins required: ", minbins)
+    print("Minimal (optimal) number of bins required: ", minbins)
     sizefree = minbins * options.maxbinsize - totalsize
-    print("# Theoretical unused space with {} bins: {:.2f} MiB"
+    print("Theoretical unused space with {} bins: {:.2f} MiB"
           .format(minbins, sizefree))
 
 
@@ -175,8 +189,8 @@ binscreated = binnumber - 1
 if options.verbose:
     sizefree = binscreated * options.maxbinsize - totalsize
     print("""\
-# {} bins created.
-# Actual unused space over the {} bins created: {:.2f} MiB"""
+{} bins created.
+Actual unused space over the {} bins created: {:.2f} MiB"""
           .format(binscreated, binscreated, sizefree))
 
 
@@ -193,17 +207,16 @@ if options.move:
     for b in bins:
         dirname = b.name()
         if os.path.exists(dirname) and not os.path.isdir(dirname):
-            print('# WARNING! File "{}" exists but is not a directory:'
-                  ' skipping bin #{}.'
-                  .format(dirname, b.id))
+            warn('File "{}" exists but is not a directory: skipping bin #{}.'
+                 .format(dirname, b.id))
             continue
         # Create the target directory:
         try:
             os.makedirs(dirname, exist_ok=True)
         except FileExistsError:
-            print('# WARNING! Directory "{}" already exists with different'
-                  ' permissions (mode). Proceeding anyway.'
-                  .format(dirname))
+            warn('Directory "{}" already exists with different permissions'
+                 ' (mode). Proceeding anyway.'
+                 .format(dirname))
         # Move the files in the directory:
         for filename in b.list_files():
             shutil.move(filename, dirname)
@@ -212,4 +225,4 @@ if options.move:
 ### Wrapping-up ###
 
 if (ignored_files):
-    print("\n# WARNING! There were ignored files, see at the top of this log.")
+    warn("There were ignored files (see prior messages).")