X-Git-Url: https://code.grnet.gr/git/snf-image-creator/blobdiff_plain/8e3065a039b08d9c37d183f8cc3bb8ae5dcd4410..7c6a41860203fcbaa8b0028ee8b059ee2f63ee81:/image_creator/util.py

diff --git a/image_creator/util.py b/image_creator/util.py
index 2805de7..a60d865 100644
--- a/image_creator/util.py
+++ b/image_creator/util.py
@@ -1,3 +1,5 @@
+# -*- coding: utf-8 -*-
+#
 # Copyright 2012 GRNET S.A. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or
@@ -31,88 +33,105 @@
 # interpreted as representing official policies, either expressed
 # or implied, of GRNET S.A.
 
-import sys
-import pbs
+"""This module provides various helper functions to be used by other parts of
+the package.
+"""
+
+import sh
 import hashlib
-from clint.textui import colored, progress as uiprogress
+import time
+import os
 
 
 class FatalError(Exception):
+    """Fatal Error exception of snf-image-creator"""
     pass
 
 
-silent = False
-
-
 def get_command(command):
+    """Return a file system binary command"""
     def find_sbin_command(command, exception):
         search_paths = ['/usr/local/sbin', '/usr/sbin', '/sbin']
         for fullpath in map(lambda x: "%s/%s" % (x, command), search_paths):
             if os.path.exists(fullpath) and os.access(fullpath, os.X_OK):
-                return pbs.Command(fullpath)
+                return sh.Command(fullpath)
         raise exception
 
     try:
-        return pbs.__getattr__(command)
-    except pbs.CommadNotFount as e:
+        return sh.__getattr__(command)
+    except sh.CommandNotFound as e:
         return find_sbin_command(command, e)
 
 
-def error(msg, new_line=True):
-    nl = "\n" if new_line else ''
-    sys.stderr.write(colored.red('Error: %s' % msg) + nl)
-
-
-def warn(msg, new_line=True):
-    if not silent:
-        nl = "\n" if new_line else ''
-        sys.stderr.write(colored.yellow("Warning: %s" % msg) + nl)
-
-
-def success(msg, new_line=True):
-    if not silent:
-        nl = "\n" if new_line else ''
-        sys.stdout.write(colored.green(msg) + nl)
-        if not nl:
-            sys.stdout.flush()
-
-
-def output(msg="", new_line=True):
-    if not silent:
-        nl = "\n" if new_line else ''
-        sys.stdout.write(msg + nl)
-        if not nl:
-            sys.stdout.flush()
-
-
-def progress(message=''):
-
-    PROGRESS_LENGTH = 32
-    MESSAGE_LENGTH = 32
-
-    def progress_generator(n=100):
-        position = 0
-        msg = message.ljust(MESSAGE_LENGTH)
-        for i in uiprogress.bar(range(n), msg, PROGRESS_LENGTH, silent):
-            if i < position:
-                continue
-            position = yield
-        yield  # suppress the StopIteration exception
-    return progress_generator
-
-def md5(filename, size, progress = None):
-
-    BLOCKSIZE = 2^22  # 4MB
-
-    md5 = hashlib.md5()
-    with open(filename, "r") as src:
-        left = size
-        while left > 0:
-            length = min(left, BLOCKSIZE)
-            data = src.read(length)
-            md5.update(data)
-            left -= length
-
-    return md5.hexdigest()
+def try_fail_repeat(command, *args):
+    """Execute a command multiple times until it succeeds"""
+    times = (0.1, 0.5, 1, 2)
+    i = iter(times)
+    while True:
+        try:
+            command(*args)
+            return
+        except sh.ErrorReturnCode:
+            try:
+                wait = i.next()
+            except StopIteration:
+                break
+            time.sleep(wait)
+
+    raise FatalError("Command: `%s %s' failed" % (command, " ".join(args)))
+
+
+def free_space(dirname):
+    """Compute the free space in a directory"""
+    stat = os.statvfs(dirname)
+    return stat.f_bavail * stat.f_frsize
+
+
+class MD5:
+    """Represents MD5 computations"""
+    def __init__(self, output):
+        """Create an MD5 instance"""
+        self.out = output
+
+    def compute(self, filename, size):
+        """Compute the MD5 checksum of a file"""
+        MB = 2 ** 20
+        BLOCKSIZE = 4 * MB  # 4MB
+
+        prog_size = ((size + MB - 1) // MB)  # in MB
+        progressbar = self.out.Progress(prog_size, "Calculating md5sum", 'mb')
+        md5 = hashlib.md5()
+        with open(filename, "r") as src:
+            left = size
+            while left > 0:
+                length = min(left, BLOCKSIZE)
+                data = src.read(length)
+                md5.update(data)
+                left -= length
+                progressbar.goto((size - left) // MB)
+
+        checksum = md5.hexdigest()
+        progressbar.success(checksum)
+
+        return checksum
+
+    def check_guestfs_version(ghandler, major, minor, release):
+        """Checks if the version of the used libguestfs is smaller, equal or
+        greater than the one specified by the major, minor and release triplet
+
+        Returns:
+            < 0 if the installed version is smaller than the specified one
+            = 0 if they are equal
+            > 0 if the installed one is greater than the specified one
+        """
+
+        ver = ghandler.version()
+
+        for (a, b) in (ver['major'], major), (ver['minor'], minor), \
+                (ver['release'], release):
+            if a != b:
+                return a - b
+
+        return 0
 
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