Start of Python code to generate likely-looking pseudo random file

trees to reproducibly test performance on specified size sets.

testhelp/maketree.py

@@ -0,0 +1,133 @@
+#! /usr/bin/python2.2
+
+# Copyright (C) 2002 by Martin Pool <mbp@samba.org>
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version
+# 2 as published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+# 
+# You should have received a copy of the GNU Lesser General Public
+# License along with this program; if not, write to the Free Software
+# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+# Populate a tree with pseudo-randomly distributed files to test
+# rsync.
+
+from __future__ import generators
+import random, string, os, os.path
+
+nfiles = 10000
+depth = 5
+n_children = 20
+n_files = 20
+n_symlinks = 10
+
+name_chars = string.digits + string.letters
+
+abuffer = 'a' * 1024
+
+def random_name_chars():
+    a = ""
+    for i in range(10):
+        a = a + random.choice(name_chars)
+    return a
+
+    
+def generate_names():
+    n = 0
+    while 1:
+        yield "%05d_%s" % (n, random_name_chars())
+        n += 1
+
+
+class TreeBuilder:
+    def __init__(self):
+        self.n_children = 20
+        self.n_files = 100
+        self.total_entries = 100000 # long(1e8)
+        self.actual_size = 0
+        self.name_gen = generate_names()
+        self.all_files = []
+        self.all_dirs = []
+        self.all_symlinks = []
+
+
+    def random_size(self):
+        return random.lognormvariate(4, 4)
+
+
+    def random_symlink_target(self):
+        what = random.choice(['directory', 'file', 'symlink', 'none'])
+        try:
+            if what == 'directory':
+                return random.choice(self.all_dirs)
+            elif what == 'file':
+                return random.choice(self.all_files)
+            elif what == 'symlink':
+                return random.choice(self.all_symlinks)
+            elif what == 'none':
+                return self.name_gen.next()
+        except IndexError:
+            return self.name_gen.next()
+
+
+    def can_continue(self):
+        self.total_entries -= 1
+        return self.total_entries > 0
+
+        
+    def build_tree(self, prefix, depth):
+        """Generate a breadth-first tree"""
+        for count, function in [[n_files, self.make_file],
+                                [n_children, self.make_child_recurse],
+                                [n_symlinks, self.make_symlink]]:
+            for i in range(count):
+                if not self.can_continue():
+                    return
+                name = os.path.join(prefix, self.name_gen.next())
+                function(name, depth)
+
+
+    def print_summary(self):
+        print "total bytes: %d" % self.actual_size
+
+
+    def make_child_recurse(self, dname, depth):
+        if depth > 1:
+            self.make_dir(dname)
+            self.build_tree(dname, depth-1)
+
+
+    def make_dir(self, dname, depth='ignore'):
+        print "%s/" % (dname)
+        os.mkdir(dname)
+        self.all_dirs.append(dname)
+
+
+    def make_symlink(self, lname, depth='ignore'):
+        print "%s -> %s" % (lname, self.random_symlink_target())
+
+
+    def make_file(self, fname, depth='ignore'):
+        size = long(self.random_size())
+        print "%-70s %d" % (fname, size)
+        f = open(fname, 'w')
+        f.truncate(size)
+        self.fill_file(f, size)
+        self.all_files.append(fname)
+        self.actual_size += size
+
+    def fill_file(self, f, size):
+        while size > 0:
+            f.write(abuffer[:size])
+            size -= len(abuffer)
+
+    
+tb = TreeBuilder()
+tb.build_tree('/tmp/foo', 3)
+tb.print_summary()