zeroinstall/injector/run.py

   1 """
   2 Executes a set of implementations as a program.
   3 """
   4
   5 # Copyright (C) 2009, Thomas Leonard
   6 # See the README file for details, or visit http://0install.net.
   7
   8 from zeroinstall import _
   9 import os, sys
  10 from logging import info
  11 from string import Template
  12
  13 from zeroinstall.injector.model import SafeException, EnvironmentBinding, ExecutableBinding, Command, Dependency
  14 from zeroinstall.injector import namespaces, qdom
  15 from zeroinstall.support import basedir
  16
  17 def do_env_binding(binding, path):
  18         """Update this process's environment by applying the binding.
  19         @param binding: the binding to apply
  20         @type binding: L{model.EnvironmentBinding}
  21         @param path: the selected implementation
  22         @type path: str"""
  23         os.environ[binding.name] = binding.get_value(path,
  24                                         os.environ.get(binding.name, None))
  25         info("%s=%s", binding.name, os.environ[binding.name])
  26
  27 def execute(policy, prog_args, dry_run = False, main = None, wrapper = None):
  28         """Execute program. On success, doesn't return. On failure, raises an Exception.
  29         Returns normally only for a successful dry run.
  30         @param policy: a policy with the selected versions
  31         @type policy: L{policy.Policy}
  32         @param prog_args: arguments to pass to the program
  33         @type prog_args: [str]
  34         @param dry_run: if True, just print a message about what would have happened
  35         @type dry_run: bool
  36         @param main: the name of the binary to run, or None to use the default
  37         @type main: str
  38         @param wrapper: a command to use to actually run the binary, or None to run the binary directly
  39         @type wrapper: str
  40         @precondition: C{policy.ready and policy.get_uncached_implementations() == []}
  41         """
  42         execute_selections(policy.solver.selections, prog_args, dry_run, main, wrapper)
  43
  44 def test_selections(selections, prog_args, dry_run, main, wrapper = None):
  45         """Run the program in a child process, collecting stdout and stderr.
  46         @return: the output produced by the process
  47         @since: 0.27
  48         """
  49         import tempfile
  50         output = tempfile.TemporaryFile(prefix = '0launch-test')
  51         try:
  52                 child = os.fork()
  53                 if child == 0:
  54                         # We are the child
  55                         try:
  56                                 try:
  57                                         os.dup2(output.fileno(), 1)
  58                                         os.dup2(output.fileno(), 2)
  59                                         execute_selections(selections, prog_args, dry_run, main)
  60                                 except:
  61                                         import traceback
  62                                         traceback.print_exc()
  63                         finally:
  64                                 sys.stdout.flush()
  65                                 sys.stderr.flush()
  66                                 os._exit(1)
  67
  68                 info(_("Waiting for test process to finish..."))
  69
  70                 pid, status = os.waitpid(child, 0)
  71                 assert pid == child
  72
  73                 output.seek(0)
  74                 results = output.read()
  75                 if status != 0:
  76                         results += _("Error from child process: exit code = %d") % status
  77         finally:
  78                 output.close()
  79
  80         return results
  81
  82 def _process_args(args, element):
  83         """Append each <arg> under <element> to args, performing $-expansion."""
  84         for child in element.childNodes:
  85                 if child.uri == namespaces.XMLNS_IFACE and child.name == 'arg':
  86                         args.append(Template(child.content).substitute(os.environ))
  87
  88 class Setup(object):
  89         """@since: 1.2"""
  90         stores = None
  91         selections = None
  92         _exec_bindings = None
  93         _checked_runenv = False
  94
  95         def __init__(self, stores, selections):
  96                 """@param stores: where to find cached implementations
  97                 @type stores: L{zerostore.Stores}"""
  98                 self.stores = stores
  99                 self.selections = selections
 100
 101         def build_command(self, command_iface, command_name, user_command = None):
 102                 """Create a list of strings to be passed to exec to run the <command>s in the selections.
 103                 @param command_iface: the interface of the program being run
 104                 @type command_iface: str
 105                 @param command_name: the name of the command being run
 106                 @type command_name: str
 107                 @param user_command: a custom command to use instead
 108                 @type user_command: L{model.Command}
 109                 @return: the argument list
 110                 @rtype: [str]"""
 111
 112                 assert command_name
 113
 114                 prog_args = []
 115                 sels = self.selections.selections
 116
 117                 while command_name:
 118                         command_sel = sels[command_iface]
 119
 120                         if user_command is None:
 121                                 command = command_sel.get_command(command_name)
 122                         else:
 123                                 command = user_command
 124                                 user_command = None
 125
 126                         command_args = []
 127
 128                         # Add extra arguments for runner
 129                         runner = command.get_runner()
 130                         if runner:
 131                                 command_iface = runner.interface
 132                                 command_name = runner.command
 133                                 _process_args(command_args, runner.qdom)
 134                         else:
 135                                 command_iface = None
 136                                 command_name = None
 137
 138                         # Add main program path
 139                         command_path = command.path
 140                         if command_path is not None:
 141                                 if command_sel.id.startswith('package:'):
 142                                         prog_path = command_path
 143                                 else:
 144                                         if command_path.startswith('/'):
 145                                                 raise SafeException(_("Command path must be relative, but '%s' starts with '/'!") %
 146                                                                         command_path)
 147                                         prog_path = os.path.join(self._get_implementation_path(command_sel), command_path)
 148
 149                                 assert prog_path is not None
 150
 151                                 if not os.path.exists(prog_path):
 152                                         raise SafeException(_("File '%(program_path)s' does not exist.\n"
 153                                                         "(implementation '%(implementation_id)s' + program '%(main)s')") %
 154                                                         {'program_path': prog_path, 'implementation_id': command_sel.id,
 155                                                         'main': command_path})
 156
 157                                 command_args.append(prog_path)
 158
 159                         # Add extra arguments for program
 160                         _process_args(command_args, command.qdom)
 161
 162                         prog_args = command_args + prog_args
 163
 164                 # Each command is run by the next, but the last one is run by exec, and we
 165                 # need a path for that.
 166                 if command.path is None:
 167                         raise SafeException("Missing 'path' attribute on <command>")
 168
 169                 return prog_args
 170
 171         def _get_implementation_path(self, impl):
 172                 return impl.local_path or self.stores.lookup_any(impl.digests)
 173
 174         def prepare_env(self):
 175                 """Do all the environment bindings in the selections (setting os.environ)."""
 176                 self._exec_bindings = []
 177
 178                 def _do_bindings(impl, bindings, dep):
 179                         for b in bindings:
 180                                 self.do_binding(impl, b, dep)
 181
 182                 def _do_deps(deps):
 183                         for dep in deps:
 184                                 dep_impl = sels.get(dep.interface, None)
 185                                 if dep_impl is None:
 186                                         assert dep.importance != Dependency.Essential, dep
 187                                 elif not dep_impl.id.startswith('package:'):
 188                                         _do_bindings(dep_impl, dep.bindings, dep)
 189
 190                 sels = self.selections.selections
 191                 for selection in sels.values():
 192                         _do_bindings(selection, selection.bindings, None)
 193                         _do_deps(selection.dependencies)
 194
 195                         # Process commands' dependencies' bindings too
 196                         for command in selection.get_commands().values():
 197                                 _do_deps(command.requires)
 198
 199                 # Do these after <environment>s, because they may do $-expansion
 200                 for binding, dep in self._exec_bindings:
 201                         self.do_exec_binding(binding, dep)
 202                 self._exec_bindings = None
 203
 204         def do_binding(self, impl, binding, dep):
 205                 """Called by L{prepare_env} for each binding.
 206                 Sub-classes may wish to override this.
 207                 @param impl: the selected implementation
 208                 @type impl: L{selections.Selection}
 209                 @param binding: the binding to be processed
 210                 @type binding: L{model.Binding}
 211                 @param dep: the dependency containing the binding, or None for implementation bindings
 212                 @type dep: L{model.Dependency}
 213                 """
 214                 if isinstance(binding, EnvironmentBinding):
 215                         do_env_binding(binding, self._get_implementation_path(impl))
 216                 elif isinstance(binding, ExecutableBinding):
 217                         self._exec_bindings.append((binding, dep))
 218
 219         def do_exec_binding(self, binding, dep):
 220                 if dep is None:
 221                         raise SafeException("<%s> can only appear within a <requires>" % binding.qdom.name)
 222                 name = binding.name
 223                 if '/' in name or name.startswith('.') or "'" in name:
 224                         raise SafeException("Invalid <executable> name '%s'" % name)
 225                 exec_dir = basedir.save_cache_path(namespaces.config_site, namespaces.config_prog, 'executables', name)
 226                 exec_path = os.path.join(exec_dir, name)
 227
 228                 if not self._checked_runenv:
 229                         self._check_runenv()
 230
 231                 if not os.path.exists(exec_path):
 232                         # Symlink ~/.cache/0install.net/injector/executables/$name/$name to runenv.py
 233                         os.symlink('../../runenv.py', exec_path)
 234                         os.chmod(exec_dir, 0o500)
 235
 236                 if binding.in_path:
 237                         path = os.environ["PATH"] = exec_dir + os.pathsep + os.environ["PATH"]
 238                         info("PATH=%s", path)
 239                 else:
 240                         os.environ[name] = exec_path
 241                         info("%s=%s", name, exec_path)
 242
 243                 import json
 244                 args = self.build_command(dep.interface, binding.command)
 245                 os.environ["0install-runenv-" + name] = json.dumps(args)
 246
 247         def _check_runenv(self):
 248                 # Create the runenv.py helper script under ~/.cache if missing or out-of-date
 249                 main_dir = basedir.save_cache_path(namespaces.config_site, namespaces.config_prog)
 250                 runenv = os.path.join(main_dir, 'runenv.py')
 251                 expected_contents = "#!%s\nfrom zeroinstall.injector import _runenv; _runenv.main()\n" % sys.executable
 252
 253                 actual_contents = None
 254                 if os.path.exists(runenv):
 255                         with open(runenv) as s:
 256                                 actual_contents = s.read()
 257
 258                 if actual_contents != expected_contents:
 259                         import tempfile
 260                         tmp = tempfile.NamedTemporaryFile('w', dir = main_dir, delete = False)
 261                         info("Updating %s", runenv)
 262                         tmp.write(expected_contents)
 263                         tmp.close()
 264                         os.chmod(tmp.name, 0555)
 265                         os.rename(tmp.name, runenv)
 266
 267                 self._checked_runenv = True
 268
 269 def execute_selections(selections, prog_args, dry_run = False, main = None, wrapper = None, stores = None):
 270         """Execute program. On success, doesn't return. On failure, raises an Exception.
 271         Returns normally only for a successful dry run.
 272         @param selections: the selected versions
 273         @type selections: L{selections.Selections}
 274         @param prog_args: arguments to pass to the program
 275         @type prog_args: [str]
 276         @param dry_run: if True, just print a message about what would have happened
 277         @type dry_run: bool
 278         @param main: the name of the binary to run, or None to use the default
 279         @type main: str
 280         @param wrapper: a command to use to actually run the binary, or None to run the binary directly
 281         @type wrapper: str
 282         @since: 0.27
 283         @precondition: All implementations are in the cache.
 284         """
 285         #assert stores is not None
 286         if stores is None:
 287                 from zeroinstall import zerostore
 288                 stores = zerostore.Stores()
 289
 290         setup = Setup(stores, selections)
 291
 292         commands = selections.commands
 293         if main is not None:
 294                 # Replace first command with user's input
 295                 if main.startswith('/'):
 296                         main = main[1:]                 # User specified a path relative to the package root
 297                 else:
 298                         old_path = commands[0].path
 299                         assert old_path, "Can't use a relative replacement main when there is no original one!"
 300                         main = os.path.join(os.path.dirname(old_path), main)    # User main is relative to command's name
 301                 # Copy all child nodes (e.g. <runner>) except for the arguments
 302                 user_command_element = qdom.Element(namespaces.XMLNS_IFACE, 'command', {'path': main})
 303                 if commands:
 304                         for child in commands[0].qdom.childNodes:
 305                                 if child.uri == namespaces.XMLNS_IFACE and child.name == 'arg':
 306                                         continue
 307                                 user_command_element.childNodes.append(child)
 308                 user_command = Command(user_command_element, None)
 309         else:
 310                 user_command = None
 311
 312         setup.prepare_env()
 313         prog_args = setup.build_command(selections.interface, selections.command, user_command) + prog_args
 314
 315         if wrapper:
 316                 prog_args = ['/bin/sh', '-c', wrapper + ' "$@"', '-'] + list(prog_args)
 317
 318         if dry_run:
 319                 print _("Would execute: %s") % ' '.join(prog_args)
 320         else:
 321                 info(_("Executing: %s"), prog_args)
 322                 sys.stdout.flush()
 323                 sys.stderr.flush()
 324                 try:
 325                         os.execv(prog_args[0], prog_args)
 326                 except OSError as ex:
 327                         raise SafeException(_("Failed to run '%(program_path)s': %(exception)s") % {'program_path': prog_args[0], 'exception': str(ex)})