zeroinstall/injector/run.py

   1 # Copyright (C) 2006, Thomas Leonard
   2 # See the README file for details, or visit http://0install.net.
   3
   4 import os, sys
   5 from logging import debug, info
   6
   7 from model import Interface, SafeException, EnvironmentBinding
   8
   9 def do_env_binding(binding, path):
  10         os.environ[binding.name] = binding.get_value(path,
  11                                         os.environ.get(binding.name, None))
  12         info("%s=%s", binding.name, os.environ[binding.name])
  13
  14 def execute(policy, prog_args, dry_run = False, main = None):
  15         iface = policy.get_interface(policy.root)
  16
  17         for needed_iface in policy.implementation:
  18                 impl = policy.implementation[needed_iface]
  19                 assert impl
  20                 for dep in impl.dependencies.values():
  21                         dep_iface = policy.get_interface(dep.interface)
  22                         for b in dep.bindings:
  23                                 if isinstance(b, EnvironmentBinding):
  24                                         dep_impl = policy.get_implementation(dep_iface)
  25                                         do_env_binding(b, policy.get_implementation_path(dep_impl))
  26
  27         root_impl = policy.get_implementation(iface)
  28         if main is None:
  29                 main = root_impl.main
  30         elif main.startswith('/'):
  31                 main = main[1:]
  32         elif root_impl.main:
  33                 main = os.path.join(os.path.dirname(root_impl.main), main)
  34
  35         if main is None:
  36                 raise SafeException("Implementation '%s' cannot be executed directly; it is just a library "
  37                                     "to be used by other programs (or missing 'main' attribute)" %
  38                                     root_impl)
  39
  40         prog_path = os.path.join(policy.get_implementation_path(root_impl), main)
  41         if not os.path.exists(prog_path):
  42                 raise SafeException("File '%s' does not exist.\n"
  43                                 "(implementation '%s' + program '%s')" %
  44                                 (prog_path, policy.implementation[iface].id, main))
  45         if dry_run:
  46                 print "Would execute:", prog_path
  47         else:
  48                 info("Executing: %s", prog_path)
  49                 sys.stdout.flush()
  50                 sys.stderr.flush()
  51                 try:
  52                         os.execl(prog_path, prog_path, *prog_args)
  53                 except OSError, ex:
  54                         raise SafeException("Failed to run '%s': %s" % (prog_path, str(ex)))