zeroinstall/injector/distro.py

   1 """
   2 Integration with native distribution package managers.
   3 @since: 0.28
   4 """
   5
   6 # Copyright (C) 2007, Thomas Leonard
   7 # See the README file for details, or visit http://0install.net.
   8
   9 import os, re
  10 from logging import warn, info
  11 from zeroinstall.injector import namespaces, model
  12 from zeroinstall.support import basedir
  13
  14 _dotted_ints = '[0-9]+(\.[0-9]+)*'
  15 _version_regexp = '(%s)(-(pre|rc|post|)%s)*' % (_dotted_ints, _dotted_ints)
  16
  17 def try_cleanup_distro_version(version):
  18         """Try to turn a distribution version string into one readable by Zero Install.
  19         We do this by stripping off anything we can't parse.
  20         @return: the part we understood, or None if we couldn't parse anything
  21         @rtype: str"""
  22         match = re.match(_version_regexp, version)
  23         if match:
  24                 return match.group(0)
  25         return None
  26
  27 class Distribution(object):
  28         """Represents a distribution with which we can integrate.
  29         Sub-classes should specialise this to integrate with the package managers of
  30         particular distributions. This base class ignores the native package manager.
  31         @since: 0.28
  32         """
  33
  34         def get_package_info(self, package, factory):
  35                 """Get information about the given package.
  36                 Add zero or more implementations using the factory (typically at most two
  37                 will be added; the currently installed version and the latest available).
  38                 @param package: package name (e.g. "gimp")
  39                 @type package: str
  40                 @param factory: function for creating new DistributionImplementation objects from IDs
  41                 @type factory: str -> L{model.DistributionImplementation}
  42                 """
  43                 return
  44
  45 class CachedDistribution(Distribution):
  46         """For distributions where querying the package database is slow (e.g. requires running
  47         an external command), we cache the results.
  48         """
  49
  50         def __init__(self, db_status_file):
  51                 """@param status_file: update the cache when the timestamp of this file changes"""
  52                 self._status_details = os.stat(db_status_file)
  53
  54                 self.versions = {}
  55                 self.cache_dir = basedir.save_cache_path(namespaces.config_site,
  56                                                          namespaces.config_prog)
  57
  58                 try:
  59                         self._load_cache()
  60                 except Exception, ex:
  61                         info("Failed to load distribution database cache (%s). Regenerating...", ex)
  62                         try:
  63                                 self.generate_cache()
  64                                 self._load_cache()
  65                         except Exception, ex:
  66                                 warn("Failed to regenerate distribution database cache: %s", ex)
  67
  68         def _load_cache(self):
  69                 """Load {cache_leaf} cache file into self.versions if it is available and up-to-date.
  70                 Throws an exception if the cache should be (re)created."""
  71                 stream = file(os.path.join(self.cache_dir, self.cache_leaf))
  72
  73                 cache_version = None
  74                 for line in stream:
  75                         if line == '\n':
  76                                 break
  77                         name, value = line.split(': ')
  78                         if name == 'mtime' and int(value) != int(self._status_details.st_mtime):
  79                                 raise Exception("Modification time of package database file has changed")
  80                         if name == 'size' and int(value) != self._status_details.st_size:
  81                                 raise Exception("Size of package database file has changed")
  82                         if name == 'version':
  83                                 cache_version = int(value)
  84                 else:
  85                         raise Exception('Invalid cache format (bad header)')
  86
  87                 if cache_version is None:
  88                         raise Exception('Old cache format')
  89
  90                 versions = self.versions
  91                 for line in stream:
  92                         package, version, zi_arch = line[:-1].split('\t')
  93                         versions[package] = (version, intern(zi_arch))
  94
  95         def _write_cache(self, cache):
  96                 #cache.sort()   # Might be useful later; currently we don't care
  97                 import tempfile
  98                 fd, tmpname = tempfile.mkstemp(prefix = 'zeroinstall-cache-tmp',
  99                                                dir = self.cache_dir)
 100                 try:
 101                         stream = os.fdopen(fd, 'wb')
 102                         stream.write('version: 2\n')
 103                         stream.write('mtime: %d\n' % int(self._status_details.st_mtime))
 104                         stream.write('size: %d\n' % self._status_details.st_size)
 105                         stream.write('\n')
 106                         for line in cache:
 107                                 stream.write(line + '\n')
 108                         stream.close()
 109
 110                         os.rename(tmpname,
 111                                   os.path.join(self.cache_dir,
 112                                                self.cache_leaf))
 113                 except:
 114                         os.unlink(tmpname)
 115                         raise
 116
 117 class DebianDistribution(CachedDistribution):
 118         """A dpkg-based distribution."""
 119
 120         cache_leaf = 'dpkg-status.cache'
 121
 122         def generate_cache(self):
 123                 cache = []
 124
 125                 for line in os.popen("dpkg-query -W --showformat='${Package}\t${Version}\t${Architecture}\n'"):
 126                         package, version, debarch = line.split('\t', 2)
 127                         if ':' in version:
 128                                 # Debian's 'epoch' system
 129                                 version = version.split(':', 1)[1]
 130                         if debarch == 'amd64\n':
 131                                 zi_arch = 'x86_64'
 132                         else:
 133                                 zi_arch = '*'
 134                         clean_version = try_cleanup_distro_version(version)
 135                         if clean_version:
 136                                 cache.append('%s\t%s\t%s' % (package, clean_version, zi_arch))
 137                         else:
 138                                 warn("Can't parse distribution version '%s' for package '%s'", version, package)
 139
 140                 self._write_cache(cache)
 141
 142         def get_package_info(self, package, factory):
 143                 try:
 144                         version, machine = self.versions[package]
 145                 except KeyError:
 146                         return
 147
 148                 impl = factory('package:deb:%s:%s' % (package, version))
 149                 impl.version = model.parse_version(version)
 150                 if machine != '*':
 151                         impl.machine = machine
 152
 153 class RPMDistribution(CachedDistribution):
 154         """An RPM-based distribution."""
 155
 156         cache_leaf = 'rpm-status.cache'
 157
 158         def generate_cache(self):
 159                 cache = []
 160
 161                 for line in os.popen("rpm -qa --qf='%{NAME}\t%{VERSION}-%{RELEASE}\t%{ARCH}\n'"):
 162                         package, version, rpmarch = line.split('\t', 2)
 163                         if package == 'gpg-pubkey':
 164                                 continue
 165                         if rpmarch == 'amd64\n':
 166                                 zi_arch = 'x86_64'
 167                         elif rpmarch == 'noarch\n' or rpmarch == "(none)\n":
 168                                 zi_arch = '*'
 169                         else:
 170                                 zi_arch = rpmarch.strip()
 171                         clean_version = try_cleanup_distro_version(version)
 172                         if clean_version:
 173                                 cache.append('%s\t%s\t%s' % (package, clean_version, zi_arch))
 174                         else:
 175                                 warn("Can't parse distribution version '%s' for package '%s'", version, package)
 176
 177                 self._write_cache(cache)
 178
 179         def get_package_info(self, package, factory):
 180                 try:
 181                         version, machine = self.versions[package]
 182                 except KeyError:
 183                         return
 184
 185                 impl = factory('package:rpm:%s:%s' % (package, version))
 186                 impl.version = model.parse_version(version)
 187                 if machine != '*':
 188                         impl.machine = machine
 189
 190 _host_distribution = None
 191 def get_host_distribution():
 192         """Get a Distribution suitable for the host operating system.
 193         Calling this twice will return the same object.
 194         @rtype: L{Distribution}"""
 195         global _host_distribution
 196         if not _host_distribution:
 197                 _dpkg_db_status = '/var/lib/dpkg/status'
 198                 _rpm_db = '/var/lib/rpm/Packages'
 199
 200                 if os.access(_dpkg_db_status, os.R_OK):
 201                         _host_distribution = DebianDistribution(_dpkg_db_status)
 202                 elif os.path.isfile(_rpm_db):
 203                         _host_distribution = RPMDistribution(_rpm_db)
 204                 else:
 205                         _host_distribution = Distribution()
 206
 207         return _host_distribution