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
  94         def __init__(self, stores, selections):
  95                 """@param stores: where to find cached implementations
  96                 @type stores: L{zerostore.Stores}"""
  97                 self.stores = stores
  98                 self.selections = selections
  99
 100         def build_command(self, command_iface, command_name, user_command = None):
 101                 """Create a list of strings to be passed to exec to run the <command>s in the selections.
 102                 @param commands: the commands to be used (taken from selections is None)
 103                 @type commands: [L{model.Command}]
 104                 @return: the argument list
 105                 @rtype: [str]"""
 106
 107                 assert command_name
 108
 109                 prog_args = []
 110                 sels = self.selections.selections
 111
 112                 while command_name:
 113                         command_sel = sels[command_iface]
 114
 115                         if user_command is None:
 116                                 command = command_sel.get_command(command_name)
 117                         else:
 118                                 command = user_command
 119                                 user_command = None
 120
 121                         command_args = []
 122
 123                         # Add extra arguments for runner
 124                         runner = command.get_runner()
 125                         if runner:
 126                                 command_iface = runner.interface
 127                                 command_name = runner.command
 128                                 _process_args(command_args, runner.qdom)
 129                         else:
 130                                 command_iface = None
 131                                 command_name = None
 132
 133                         # Add main program path
 134                         command_path = command.path
 135                         if command_path is not None:
 136                                 if command_sel.id.startswith('package:'):
 137                                         prog_path = command_path
 138                                 else:
 139                                         if command_path.startswith('/'):
 140                                                 raise SafeException(_("Command path must be relative, but '%s' starts with '/'!") %
 141                                                                         command_path)
 142                                         prog_path = os.path.join(self._get_implementation_path(command_sel), command_path)
 143
 144                                 assert prog_path is not None
 145
 146                                 if not os.path.exists(prog_path):
 147                                         raise SafeException(_("File '%(program_path)s' does not exist.\n"
 148                                                         "(implementation '%(implementation_id)s' + program '%(main)s')") %
 149                                                         {'program_path': prog_path, 'implementation_id': command_sel.id,
 150                                                         'main': command_path})
 151
 152                                 command_args.append(prog_path)
 153
 154                         # Add extra arguments for program
 155                         _process_args(command_args, command.qdom)
 156
 157                         prog_args = command_args + prog_args
 158
 159                 # Each command is run by the next, but the last one is run by exec, and we
 160                 # need a path for that.
 161                 if command.path is None:
 162                         raise SafeException("Missing 'path' attribute on <command>")
 163
 164                 return prog_args
 165
 166         def _get_implementation_path(self, impl):
 167                 return impl.local_path or self.stores.lookup_any(impl.digests)
 168
 169         def prepare_env(self):
 170                 """Do all the environment bindings in the selections (setting os.environ)."""
 171                 self._exec_bindings = []
 172
 173                 def _do_bindings(impl, bindings, dep):
 174                         for b in bindings:
 175                                 self.do_binding(impl, b, dep)
 176
 177                 def _do_deps(deps):
 178                         for dep in deps:
 179                                 dep_impl = sels.get(dep.interface, None)
 180                                 if dep_impl is None:
 181                                         assert dep.importance != Dependency.Essential, dep
 182                                 elif not dep_impl.id.startswith('package:'):
 183                                         _do_bindings(dep_impl, dep.bindings, dep)
 184
 185                 sels = self.selections.selections
 186                 for selection in sels.values():
 187                         _do_bindings(selection, selection.bindings, None)
 188                         _do_deps(selection.dependencies)
 189
 190                         # Process commands' dependencies' bindings too
 191                         for command in selection.get_commands().values():
 192                                 _do_deps(command.requires)
 193
 194                 # Do these after <environment>s, because they may do $-expansion
 195                 for binding, dep in self._exec_bindings:
 196                         self.do_exec_binding(binding, dep)
 197                 self._exec_bindings = None
 198
 199         def do_binding(self, impl, binding, dep):
 200                 """Called by L{prepare_env} for each binding.
 201                 Sub-classes may wish to override this.
 202                 @param impl: the selected implementation
 203                 @type impl: L{selections.Selection}
 204                 @param binding: the binding to be processed
 205                 @type binding: L{model.Binding}
 206                 @param dep: the dependency containing the binding, or None for implementation bindings
 207                 @type dep: L{model.Dependency}
 208                 """
 209                 if isinstance(binding, EnvironmentBinding):
 210                         do_env_binding(binding, self._get_implementation_path(impl))
 211                 elif isinstance(binding, ExecutableBinding):
 212                         self._exec_bindings.append((binding, dep))
 213
 214         def do_exec_binding(self, binding, dep):
 215                 if dep is None:
 216                         raise SafeException("<executable> can only appear within a <requires>")
 217                 if dep.command is None:
 218                         raise SafeException("<executable> can only appear within a <requires> with a command attribute set")
 219                 name = binding.name
 220                 if '/' in name or name.startswith('.') or "'" in name:
 221                         raise SafeException("Invalid <executable> name '%s'" % name)
 222                 exec_dir = basedir.save_cache_path(namespaces.config_site, namespaces.config_prog, 'executables', name)
 223                 exec_path = os.path.join(exec_dir, name)
 224                 if not os.path.exists(exec_path):
 225                         import tempfile
 226
 227                         # Create the runenv.py helper script under ~/.cache if missing
 228                         main_dir = basedir.save_cache_path(namespaces.config_site, namespaces.config_prog)
 229                         runenv = os.path.join(main_dir, 'runenv.py')
 230                         if not os.path.exists(runenv):
 231                                 tmp = tempfile.NamedTemporaryFile('w', dir = main_dir, delete = False)
 232                                 tmp.write("#!%s\nfrom zeroinstall.injector import _runenv; _runenv.main()" % sys.executable)
 233                                 tmp.close()
 234                                 os.chmod(tmp.name, 0555)
 235                                 os.rename(tmp.name, runenv)
 236
 237                         # Symlink ~/.cache/0install.net/injector/executables/$name/$name to runenv.py
 238                         os.symlink('../../runenv.py', exec_path)
 239
 240                 path = os.environ["PATH"] = exec_dir + os.pathsep + os.environ["PATH"]
 241                 info("PATH=%s", path)
 242
 243                 import json
 244                 args = self.build_command(dep.interface, dep.command)
 245                 os.environ["0install-runenv-" + name] = json.dumps(args)
 246
 247 def execute_selections(selections, prog_args, dry_run = False, main = None, wrapper = None, stores = None):
 248         """Execute program. On success, doesn't return. On failure, raises an Exception.
 249         Returns normally only for a successful dry run.
 250         @param selections: the selected versions
 251         @type selections: L{selections.Selections}
 252         @param prog_args: arguments to pass to the program
 253         @type prog_args: [str]
 254         @param dry_run: if True, just print a message about what would have happened
 255         @type dry_run: bool
 256         @param main: the name of the binary to run, or None to use the default
 257         @type main: str
 258         @param wrapper: a command to use to actually run the binary, or None to run the binary directly
 259         @type wrapper: str
 260         @since: 0.27
 261         @precondition: All implementations are in the cache.
 262         """
 263         #assert stores is not None
 264         if stores is None:
 265                 from zeroinstall import zerostore
 266                 stores = zerostore.Stores()
 267
 268         setup = Setup(stores, selections)
 269
 270         commands = selections.commands
 271         if main is not None:
 272                 # Replace first command with user's input
 273                 if main.startswith('/'):
 274                         main = main[1:]                 # User specified a path relative to the package root
 275                 else:
 276                         old_path = commands[0].path
 277                         assert old_path, "Can't use a relative replacement main when there is no original one!"
 278                         main = os.path.join(os.path.dirname(old_path), main)    # User main is relative to command's name
 279                 # Copy all child nodes (e.g. <runner>) except for the arguments
 280                 user_command_element = qdom.Element(namespaces.XMLNS_IFACE, 'command', {'path': main})
 281                 if commands:
 282                         for child in commands[0].qdom.childNodes:
 283                                 if child.uri == namespaces.XMLNS_IFACE and child.name == 'arg':
 284                                         continue
 285                                 user_command_element.childNodes.append(child)
 286                 user_command = Command(user_command_element, None)
 287         else:
 288                 user_command = None
 289
 290         setup.prepare_env()
 291         prog_args = setup.build_command(selections.interface, selections.command, user_command) + prog_args
 292
 293         if wrapper:
 294                 prog_args = ['/bin/sh', '-c', wrapper + ' "$@"', '-'] + list(prog_args)
 295
 296         if dry_run:
 297                 print _("Would execute: %s") % ' '.join(prog_args)
 298         else:
 299                 info(_("Executing: %s"), prog_args)
 300                 sys.stdout.flush()
 301                 sys.stderr.flush()
 302                 try:
 303                         os.execv(prog_args[0], prog_args)
 304                 except OSError as ex:
 305                         raise SafeException(_("Failed to run '%(program_path)s': %(exception)s") % {'program_path': prog_args[0], 'exception': str(ex)})