blob: e9e77dca2fcd24fdf6ea9038fa3a339ebf2ac7da [file] [log] [blame]
#!/usr/bin/env vpython
# Copyright 2014 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Can be used to point environment variable to hermetic Go toolset.
Usage (on linux and mac):
$ eval `./env.py`
$ go version
Or it can be used to wrap a command:
$ ./env.py go version
"""
assert __name__ == '__main__'
import imp
import os
import pipes
import subprocess
import sys
# Do not want to mess with sys.path, load the module directly.
bootstrap = imp.load_source(
'bootstrap', os.path.join(os.path.dirname(__file__), 'bootstrap.py'))
old = os.environ.copy()
def _escape_special(v):
"""Returns (str): The supplied value, with special shell characters escaped.
Replace special characters with their escaped form. This will allow them
to be interpreted by the shell using the $'...' notation.
Args:
v (str): The input value to escape.
"""
for f, r in (
('\n', '\\n'),
('\b', '\\b'),
('\r', '\\r'),
('\t', '\\t'),
('\v', '\\v')):
v = v.replace(f, r)
return v
if sys.platform == 'win32':
def emit_env_var(key, value):
# TODO: The quoting here is probably insufficient for all corner cases.
# We strip "'" because cmd.exe doesn't like it in PATH for some reason.
print 'set %s=%s' % (key, pipes.quote(value).strip("'"))
else:
def emit_env_var(key, value):
orig_value, value = value, _escape_special(value)
# We will only use the $'...' notation if there was an escaped character
# in the string.
print 'export %s=%s%s' % (key, ('$') if orig_value != value else (''),
pipes.quote(value))
def main():
args = sys.argv[1:]
if args and args[0] == '--':
args.pop(0)
new = bootstrap.prepare_go_environ()
if not args:
for key, value in sorted(new.iteritems()):
if old.get(key) != value:
emit_env_var(key, value)
# VIRTUAL_ENV is added by the vpython wrapper. It usually *does not* exist
# in os.environ of the outer shell that executes eval `./env.py`. Since we
# are about to replace the native python in PATH with virtualenv's one, we
# must also make sure the new environment has VIRTUAL_ENV set. Otherwise
# some virtualenv-aware tools (like gcloud) get confused.
#
# Note that once env.py finishes execution, nothing is holding a lock on
# vpython virtualenv directory, and it may eventually be garbage collected
# (while the user is still inside a shell that references it). We assume it
# is rare, and the users can manually recover (by reexecuting env.py). This
# won't be happening on bots, since they don't use eval `./env.py`.
if 'VIRTUAL_ENV' in old:
emit_env_var('VIRTUAL_ENV', old['VIRTUAL_ENV'])
if sys.platform != 'win32' and sys.stdout.isatty():
print
print '# !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!'
print '# WRAP THIS COMMAND IN "eval" TO HAVE AN EFFECT!'
print '# eval `./env.py`'
print '# !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!'
else:
exe = args[0]
if exe == 'python':
exe = sys.executable
else:
# Help Windows to find the executable in new PATH, do it only when
# executable is referenced by name (and not by path).
if os.sep not in exe:
exe = bootstrap.find_executable(exe, [bootstrap.WORKSPACE])
sys.exit(subprocess.call([exe] + args[1:], env=new))
assert __name__ == '__main__'
main()