# Copyright 2013-2024 Lawrence Livermore National Security, LLC and other
# Spack Project Developers. See the top-level COPYRIGHT file for details.
#
# SPDX-License-Identifier: (Apache-2.0 OR MIT)
"""Set, unset or modify environment variables."""
import collections
import contextlib
import inspect
import json
import os
import os.path
import pickle
import re
import sys
from functools import wraps
from typing import Any, Callable, Dict, List, MutableMapping, Optional, Tuple, Union
from llnl.path import path_to_os_path, system_path_filter
from llnl.util import tty
from llnl.util.lang import dedupe
from .executable import Executable, which
if sys.platform == "win32":
SYSTEM_PATHS = [
"C:\\",
"C:\\Program Files",
"C:\\Program Files (x86)",
"C:\\Users",
"C:\\ProgramData",
]
SUFFIXES = []
else:
SYSTEM_PATHS = ["/", "/usr", "/usr/local"]
SUFFIXES = ["bin", "bin64", "include", "lib", "lib64"]
SYSTEM_DIRS = [os.path.join(p, s) for s in SUFFIXES for p in SYSTEM_PATHS] + SYSTEM_PATHS
_SHELL_SET_STRINGS = {
"sh": "export {0}={1};\n",
"csh": "setenv {0} {1};\n",
"fish": "set -gx {0} {1};\n",
"bat": 'set "{0}={1}"\n',
"pwsh": "$Env:{0}='{1}'\n",
}
_SHELL_UNSET_STRINGS = {
"sh": "unset {0};\n",
"csh": "unsetenv {0};\n",
"fish": "set -e {0};\n",
"bat": 'set "{0}="\n',
"pwsh": "Set-Item -Path Env:{0}\n",
}
TRACING_ENABLED = False
Path = str
ModificationList = List[Union["NameModifier", "NameValueModifier"]]
_find_unsafe = re.compile(r"[^\w@%+=:,./-]", re.ASCII).search
[docs]
def double_quote_escape(s):
"""Return a shell-escaped version of the string *s*.
This is similar to how shlex.quote works, but it escapes with double quotes
instead of single quotes, to allow environment variable expansion within
quoted strings.
"""
if not s:
return '""'
if _find_unsafe(s) is None:
return s
# use double quotes, and escape double quotes in the string
# the string $"b is then quoted as "$\"b"
return '"' + s.replace('"', r"\"") + '"'
[docs]
def system_env_normalize(func):
"""Decorator wrapping calls to system env modifications,
converting all env variable names to all upper case on Windows, no-op
on other platforms before calling env modification method.
Windows, due to a DOS holdover, treats all env variable names case
insensitively, however Spack's env modification class does not,
meaning setting `Path` and `PATH` would be distinct env operations
for Spack, but would cause a collision when actually performing the
env modification operations on the env.
Normalize all env names to all caps to prevent this collision from the
Spack side."""
@wraps(func)
def case_insensitive_modification(self, name: str, *args, **kwargs):
if sys.platform == "win32":
name = name.upper()
return func(self, name, *args, **kwargs)
return case_insensitive_modification
[docs]
def is_system_path(path: Path) -> bool:
"""Returns True if the argument is a system path, False otherwise."""
return bool(path) and (os.path.normpath(path) in SYSTEM_DIRS)
[docs]
def filter_system_paths(paths: List[Path]) -> List[Path]:
"""Returns a copy of the input where system paths are filtered out."""
return [p for p in paths if not is_system_path(p)]
[docs]
def deprioritize_system_paths(paths: List[Path]) -> List[Path]:
"""Reorders input paths by putting system paths at the end of the list, otherwise
preserving order.
"""
return list(sorted(paths, key=is_system_path))
[docs]
def prune_duplicate_paths(paths: List[Path]) -> List[Path]:
"""Returns the input list with duplicates removed, otherwise preserving order."""
return list(dedupe(paths))
[docs]
def get_path(name: str) -> List[Path]:
"""Given the name of an environment variable containing multiple
paths separated by 'os.pathsep', returns a list of the paths.
"""
path = os.environ.get(name, "").strip()
if path:
return path.split(os.pathsep)
return []
[docs]
def env_flag(name: str) -> bool:
"""Given the name of an environment variable, returns True if it is set to
'true' or to '1', False otherwise.
"""
if name in os.environ:
value = os.environ[name].lower()
return value in ("true", "1")
return False
[docs]
def path_set(var_name: str, directories: List[Path]):
"""Sets the variable passed as input to the `os.pathsep` joined list of directories."""
path_str = os.pathsep.join(str(dir) for dir in directories)
os.environ[var_name] = path_str
[docs]
def path_put_first(var_name: str, directories: List[Path]):
"""Puts the provided directories first in the path, adding them
if they're not already there.
"""
path = os.environ.get(var_name, "").split(os.pathsep)
for directory in directories:
if directory in path:
path.remove(directory)
new_path = list(directories) + list(path)
path_set(var_name, new_path)
BASH_FUNCTION_FINDER = re.compile(r"BASH_FUNC_(.*?)\(\)")
def _win_env_var_to_set_line(var: str, val: str) -> str:
is_pwsh = os.environ.get("SPACK_SHELL", None) == "pwsh"
env_set_phrase = f"$Env:{var}={val}" if is_pwsh else f'set "{var}={val}"'
return env_set_phrase
def _nix_env_var_to_source_line(var: str, val: str) -> str:
if var.startswith("BASH_FUNC"):
source_line = "function {fname}{decl}; export -f {fname}".format(
fname=BASH_FUNCTION_FINDER.sub(r"\1", var), decl=val
)
else:
source_line = f"{var}={double_quote_escape(val)}; export {var}"
return source_line
def _env_var_to_source_line(var: str, val: str) -> str:
if sys.platform == "win32":
return _win_env_var_to_set_line(var, val)
else:
return _nix_env_var_to_source_line(var, val)
[docs]
@system_path_filter(arg_slice=slice(1))
def dump_environment(path: Path, environment: Optional[MutableMapping[str, str]] = None):
"""Dump an environment dictionary to a source-able file.
Args:
path: path of the file to write
environment: environment to be writte. If None os.environ is used.
"""
use_env = environment or os.environ
hidden_vars = {"PS1", "PWD", "OLDPWD", "TERM_SESSION_ID"}
file_descriptor = os.open(path, os.O_WRONLY | os.O_CREAT | os.O_TRUNC, 0o600)
with os.fdopen(file_descriptor, "w") as env_file:
for var, val in sorted(use_env.items()):
env_file.write(
"".join(
["#" if var in hidden_vars else "", _env_var_to_source_line(var, val), "\n"]
)
)
[docs]
@system_path_filter(arg_slice=slice(1))
def pickle_environment(path: Path, environment: Optional[Dict[str, str]] = None):
"""Pickle an environment dictionary to a file."""
with open(path, "wb") as pickle_file:
pickle.dump(dict(environment if environment else os.environ), pickle_file, protocol=2)
[docs]
@contextlib.contextmanager
def set_env(**kwargs):
"""Temporarily sets and restores environment variables.
Variables can be set as keyword arguments to this function.
"""
saved = {}
for var, value in kwargs.items():
if var in os.environ:
saved[var] = os.environ[var]
if value is None:
if var in os.environ:
del os.environ[var]
else:
os.environ[var] = value
yield
for var, value in kwargs.items():
if var in saved:
os.environ[var] = saved[var]
else:
if var in os.environ:
del os.environ[var]
[docs]
class Trace:
"""Trace information on a function call"""
__slots__ = ("filename", "lineno", "context")
def __init__(self, *, filename: str, lineno: int, context: str):
self.filename = filename
self.lineno = lineno
self.context = context
def __str__(self):
return f"{self.context} at {self.filename}:{self.lineno}"
def __repr__(self):
return f"Trace(filename={self.filename}, lineno={self.lineno}, context={self.context})"
[docs]
class NameModifier:
"""Base class for modifiers that act on the environment variable as a whole, and thus
store just its name
"""
__slots__ = ("name", "separator", "trace")
def __init__(self, name: str, *, separator: str = os.pathsep, trace: Optional[Trace] = None):
self.name = name
self.separator = separator
self.trace = trace
def __eq__(self, other: object):
if not isinstance(other, NameModifier):
return NotImplemented
return self.name == other.name
[docs]
def execute(self, env: MutableMapping[str, str]):
"""Apply the modification to the mapping passed as input"""
raise NotImplementedError("must be implemented by derived classes")
[docs]
class NameValueModifier:
"""Base class for modifiers that modify the value of an environment variable."""
__slots__ = ("name", "value", "separator", "trace")
def __init__(
self, name: str, value: Any, *, separator: str = os.pathsep, trace: Optional[Trace] = None
):
self.name = name
self.value = value
self.separator = separator
self.trace = trace
def __eq__(self, other: object):
if not isinstance(other, NameValueModifier):
return NotImplemented
return (
self.name == other.name
and self.value == other.value
and self.separator == other.separator
)
[docs]
def execute(self, env: MutableMapping[str, str]):
"""Apply the modification to the mapping passed as input"""
raise NotImplementedError("must be implemented by derived classes")
[docs]
class SetEnv(NameValueModifier):
__slots__ = ("force", "raw")
def __init__(
self,
name: str,
value: str,
*,
trace: Optional[Trace] = None,
force: bool = False,
raw: bool = False,
):
super().__init__(name, value, trace=trace)
self.force = force
self.raw = raw
[docs]
def execute(self, env: MutableMapping[str, str]):
tty.debug(f"SetEnv: {self.name}={str(self.value)}", level=3)
env[self.name] = str(self.value)
[docs]
class AppendFlagsEnv(NameValueModifier):
[docs]
def execute(self, env: MutableMapping[str, str]):
tty.debug(f"AppendFlagsEnv: {self.name}={str(self.value)}", level=3)
if self.name in env and env[self.name]:
env[self.name] += self.separator + str(self.value)
else:
env[self.name] = str(self.value)
[docs]
class UnsetEnv(NameModifier):
[docs]
def execute(self, env: MutableMapping[str, str]):
tty.debug(f"UnsetEnv: {self.name}", level=3)
# Avoid throwing if the variable was not set
env.pop(self.name, None)
[docs]
class RemoveFlagsEnv(NameValueModifier):
[docs]
def execute(self, env: MutableMapping[str, str]):
tty.debug(f"RemoveFlagsEnv: {self.name}-{str(self.value)}", level=3)
environment_value = env.get(self.name, "")
flags = environment_value.split(self.separator) if environment_value else []
flags = [f for f in flags if f != self.value]
env[self.name] = self.separator.join(flags)
[docs]
class SetPath(NameValueModifier):
[docs]
def execute(self, env: MutableMapping[str, str]):
string_path = self.separator.join(str(item) for item in self.value)
tty.debug(f"SetPath: {self.name}={string_path}", level=3)
env[self.name] = string_path
[docs]
class AppendPath(NameValueModifier):
[docs]
def execute(self, env: MutableMapping[str, str]):
tty.debug(f"AppendPath: {self.name}+{str(self.value)}", level=3)
environment_value = env.get(self.name, "")
directories = environment_value.split(self.separator) if environment_value else []
directories.append(path_to_os_path(os.path.normpath(self.value)).pop())
env[self.name] = self.separator.join(directories)
[docs]
class PrependPath(NameValueModifier):
[docs]
def execute(self, env: MutableMapping[str, str]):
tty.debug(f"PrependPath: {self.name}+{str(self.value)}", level=3)
environment_value = env.get(self.name, "")
directories = environment_value.split(self.separator) if environment_value else []
directories = [path_to_os_path(os.path.normpath(self.value)).pop()] + directories
env[self.name] = self.separator.join(directories)
[docs]
class RemovePath(NameValueModifier):
[docs]
def execute(self, env: MutableMapping[str, str]):
tty.debug(f"RemovePath: {self.name}-{str(self.value)}", level=3)
environment_value = env.get(self.name, "")
directories = environment_value.split(self.separator)
directories = [
path_to_os_path(os.path.normpath(x)).pop()
for x in directories
if x != path_to_os_path(os.path.normpath(self.value)).pop()
]
env[self.name] = self.separator.join(directories)
[docs]
class DeprioritizeSystemPaths(NameModifier):
[docs]
def execute(self, env: MutableMapping[str, str]):
tty.debug(f"DeprioritizeSystemPaths: {self.name}", level=3)
environment_value = env.get(self.name, "")
directories = environment_value.split(self.separator) if environment_value else []
directories = deprioritize_system_paths(
[path_to_os_path(os.path.normpath(x)).pop() for x in directories]
)
env[self.name] = self.separator.join(directories)
[docs]
class PruneDuplicatePaths(NameModifier):
[docs]
def execute(self, env: MutableMapping[str, str]):
tty.debug(f"PruneDuplicatePaths: {self.name}", level=3)
environment_value = env.get(self.name, "")
directories = environment_value.split(self.separator) if environment_value else []
directories = prune_duplicate_paths(
[path_to_os_path(os.path.normpath(x)).pop() for x in directories]
)
env[self.name] = self.separator.join(directories)
[docs]
class EnvironmentModifications:
"""Keeps track of requests to modify the current environment."""
def __init__(
self, other: Optional["EnvironmentModifications"] = None, traced: Union[None, bool] = None
):
"""Initializes a new instance, copying commands from 'other'
if it is not None.
Args:
other: list of environment modifications to be extended (optional)
traced: enable or disable stack trace inspection to log the origin
of the environment modifications
"""
self.traced = TRACING_ENABLED if traced is None else bool(traced)
self.env_modifications: List[Union[NameModifier, NameValueModifier]] = []
if other is not None:
self.extend(other)
def __iter__(self):
return iter(self.env_modifications)
def __len__(self):
return len(self.env_modifications)
[docs]
def extend(self, other: "EnvironmentModifications"):
self._check_other(other)
self.env_modifications.extend(other.env_modifications)
@staticmethod
def _check_other(other: "EnvironmentModifications"):
if not isinstance(other, EnvironmentModifications):
raise TypeError("other must be an instance of EnvironmentModifications")
def _trace(self) -> Optional[Trace]:
"""Returns a trace object if tracing is enabled, else None."""
if not self.traced:
return None
stack = inspect.stack()
try:
_, filename, lineno, _, context, index = stack[2]
assert index is not None, "index must be an integer"
current_context = context[index].strip() if context is not None else "unknown context"
except Exception:
filename = "unknown file"
lineno = -1
current_context = "unknown context"
return Trace(filename=filename, lineno=lineno, context=current_context)
[docs]
@system_env_normalize
def set(self, name: str, value: str, *, force: bool = False, raw: bool = False):
"""Stores a request to set an environment variable.
Args:
name: name of the environment variable
value: value of the environment variable
force: if True, audit will not consider this modification a warning
raw: if True, format of value string is skipped
"""
item = SetEnv(name, value, trace=self._trace(), force=force, raw=raw)
self.env_modifications.append(item)
[docs]
@system_env_normalize
def append_flags(self, name: str, value: str, sep: str = " "):
"""Stores a request to append 'flags' to an environment variable.
Args:
name: name of the environment variable
value: flags to be appended
sep: separator for the flags (default: " ")
"""
item = AppendFlagsEnv(name, value, separator=sep, trace=self._trace())
self.env_modifications.append(item)
[docs]
@system_env_normalize
def unset(self, name: str):
"""Stores a request to unset an environment variable.
Args:
name: name of the environment variable
"""
item = UnsetEnv(name, trace=self._trace())
self.env_modifications.append(item)
[docs]
@system_env_normalize
def remove_flags(self, name: str, value: str, sep: str = " "):
"""Stores a request to remove flags from an environment variable
Args:
name: name of the environment variable
value: flags to be removed
sep: separator for the flags (default: " ")
"""
item = RemoveFlagsEnv(name, value, separator=sep, trace=self._trace())
self.env_modifications.append(item)
[docs]
@system_env_normalize
def set_path(self, name: str, elements: List[str], separator: str = os.pathsep):
"""Stores a request to set an environment variable to a list of paths,
separated by a character defined in input.
Args:
name: name of the environment variable
elements: ordered list paths
separator: separator for the paths (default: os.pathsep)
"""
item = SetPath(name, elements, separator=separator, trace=self._trace())
self.env_modifications.append(item)
[docs]
@system_env_normalize
def append_path(self, name: str, path: str, separator: str = os.pathsep):
"""Stores a request to append a path to list of paths.
Args:
name: name of the environment variable
path: path to be appended
separator: separator for the paths (default: os.pathsep)
"""
item = AppendPath(name, path, separator=separator, trace=self._trace())
self.env_modifications.append(item)
[docs]
@system_env_normalize
def prepend_path(self, name: str, path: str, separator: str = os.pathsep):
"""Stores a request to prepend a path to list of paths.
Args:
name: name of the environment variable
path: path to be prepended
separator: separator for the paths (default: os.pathsep)
"""
item = PrependPath(name, path, separator=separator, trace=self._trace())
self.env_modifications.append(item)
[docs]
@system_env_normalize
def remove_path(self, name: str, path: str, separator: str = os.pathsep):
"""Stores a request to remove a path from a list of paths.
Args:
name: name of the environment variable
path: path to be removed
separator: separator for the paths (default: os.pathsep)
"""
item = RemovePath(name, path, separator=separator, trace=self._trace())
self.env_modifications.append(item)
[docs]
@system_env_normalize
def deprioritize_system_paths(self, name: str, separator: str = os.pathsep):
"""Stores a request to deprioritize system paths in a path list,
otherwise preserving the order.
Args:
name: name of the environment variable
separator: separator for the paths (default: os.pathsep)
"""
item = DeprioritizeSystemPaths(name, separator=separator, trace=self._trace())
self.env_modifications.append(item)
[docs]
@system_env_normalize
def prune_duplicate_paths(self, name: str, separator: str = os.pathsep):
"""Stores a request to remove duplicates from a path list, otherwise
preserving the order.
Args:
name: name of the environment variable
separator: separator for the paths (default: os.pathsep)
"""
item = PruneDuplicatePaths(name, separator=separator, trace=self._trace())
self.env_modifications.append(item)
[docs]
def group_by_name(self) -> Dict[str, ModificationList]:
"""Returns a dict of the current modifications keyed by variable name."""
modifications = collections.defaultdict(list)
for item in self:
modifications[item.name].append(item)
return modifications
[docs]
def drop(self, *name) -> bool:
"""Drop all modifications to the variable with the given name."""
old_mods = self.env_modifications
new_mods = [x for x in self.env_modifications if x.name not in name]
self.env_modifications = new_mods
return len(old_mods) != len(new_mods)
[docs]
def is_unset(self, variable_name: str) -> bool:
"""Returns True if the last modification to a variable is to unset it, False otherwise."""
modifications = self.group_by_name()
if variable_name not in modifications:
return False
# The last modification must unset the variable for it to be considered unset
return isinstance(modifications[variable_name][-1], UnsetEnv)
[docs]
def clear(self):
"""Clears the current list of modifications."""
self.env_modifications = []
[docs]
def reversed(self) -> "EnvironmentModifications":
"""Returns the EnvironmentModifications object that will reverse self
Only creates reversals for additions to the environment, as reversing
``unset`` and ``remove_path`` modifications is impossible.
Reversable operations are set(), prepend_path(), append_path(),
set_path(), and append_flags().
"""
rev = EnvironmentModifications()
for envmod in reversed(self.env_modifications):
if isinstance(envmod, SetEnv):
tty.debug("Reversing `Set` environment operation may lose the original value")
rev.unset(envmod.name)
elif isinstance(envmod, AppendPath):
rev.remove_path(envmod.name, envmod.value)
elif isinstance(envmod, PrependPath):
rev.remove_path(envmod.name, envmod.value)
elif isinstance(envmod, SetPath):
tty.debug("Reversing `SetPath` environment operation may lose the original value")
rev.unset(envmod.name)
elif isinstance(envmod, AppendFlagsEnv):
rev.remove_flags(envmod.name, envmod.value)
else:
tty.warn(
f"Skipping reversal of unreversable operation {type(envmod)} {envmod.name}"
)
return rev
[docs]
def apply_modifications(self, env: Optional[MutableMapping[str, str]] = None):
"""Applies the modifications and clears the list.
Args:
env: environment to be modified. If None, os.environ will be used.
"""
env = os.environ if env is None else env
modifications = self.group_by_name()
for _, actions in sorted(modifications.items()):
for modifier in actions:
modifier.execute(env)
[docs]
def shell_modifications(
self,
shell: str = "sh" if sys.platform != "win32" else os.environ.get("SPACK_SHELL", "bat"),
explicit: bool = False,
env: Optional[MutableMapping[str, str]] = None,
) -> str:
"""Return shell code to apply the modifications and clears the list."""
modifications = self.group_by_name()
env = os.environ if env is None else env
new_env = dict(env.items())
for _, actions in sorted(modifications.items()):
for modifier in actions:
modifier.execute(new_env)
if "MANPATH" in new_env and not new_env["MANPATH"].endswith(":"):
new_env["MANPATH"] += ":"
cmds = ""
for name in sorted(set(modifications)):
new = new_env.get(name, None)
old = env.get(name, None)
if explicit or new != old:
if new is None:
cmds += _SHELL_UNSET_STRINGS[shell].format(name)
else:
if sys.platform != "win32":
new_env_name = double_quote_escape(new_env[name])
else:
new_env_name = new_env[name]
cmd = _SHELL_SET_STRINGS[shell].format(name, new_env_name)
cmds += cmd
return cmds
[docs]
@staticmethod
def from_sourcing_file(
filename: Path, *arguments: str, **kwargs: Any
) -> "EnvironmentModifications":
"""Returns the environment modifications that have the same effect as
sourcing the input file.
Args:
filename: the file to be sourced
*arguments: arguments to pass on the command line
Keyword Args:
shell (str): the shell to use (default: ``bash``)
shell_options (str): options passed to the shell (default: ``-c``)
source_command (str): the command to run (default: ``source``)
suppress_output (str): redirect used to suppress output of command
(default: ``&> /dev/null``)
concatenate_on_success (str): operator used to execute a command
only when the previous command succeeds (default: ``&&``)
exclude ([str or re]): ignore any modifications of these
variables (default: [])
include ([str or re]): always respect modifications of these
variables (default: []). Supersedes any excluded variables.
clean (bool): in addition to removing empty entries,
also remove duplicate entries (default: False).
"""
tty.debug(f"EnvironmentModifications.from_sourcing_file: {filename}")
# Check if the file actually exists
if not os.path.isfile(filename):
msg = f"Trying to source non-existing file: {filename}"
raise RuntimeError(msg)
# Prepare include and exclude lists of environment variable names
exclude = kwargs.get("exclude", [])
include = kwargs.get("include", [])
clean = kwargs.get("clean", False)
# Other variables unrelated to sourcing a file
exclude.extend(
[
# Bash internals
"SHLVL",
"_",
"PWD",
"OLDPWD",
"PS1",
"PS2",
"ENV",
# Environment Modules or Lmod
"LOADEDMODULES",
"_LMFILES_",
"MODULEPATH",
"MODULERCFILE",
"BASH_FUNC_ml()",
"BASH_FUNC_module()",
# Environment Modules-specific configuration
"MODULESHOME",
"BASH_FUNC__module_raw()",
r"MODULES_(.*)",
r"__MODULES_(.*)",
r"(\w*)_mod(quar|share)",
# Lmod-specific configuration
r"LMOD_(.*)",
]
)
# Compute the environments before and after sourcing
before = sanitize(
environment_after_sourcing_files(os.devnull, **kwargs),
exclude=exclude,
include=include,
)
file_and_args = (filename,) + arguments
after = sanitize(
environment_after_sourcing_files(file_and_args, **kwargs),
exclude=exclude,
include=include,
)
# Delegate to the other factory
return EnvironmentModifications.from_environment_diff(before, after, clean)
[docs]
@staticmethod
def from_environment_diff(
before: MutableMapping[str, str], after: MutableMapping[str, str], clean: bool = False
) -> "EnvironmentModifications":
"""Constructs the environment modifications from the diff of two environments.
Args:
before: environment before the modifications are applied
after: environment after the modifications are applied
clean: in addition to removing empty entries, also remove duplicate entries
"""
# Fill the EnvironmentModifications instance
env = EnvironmentModifications()
# New variables
new_variables = list(set(after) - set(before))
# Variables that have been unset
unset_variables = list(set(before) - set(after))
# Variables that have been modified
common_variables = set(before).intersection(set(after))
modified_variables = [x for x in common_variables if before[x] != after[x]]
# Consistent output order - looks nicer, easier comparison...
new_variables.sort()
unset_variables.sort()
modified_variables.sort()
def return_separator_if_any(*args):
separators = ":", ";"
for separator in separators:
for arg in args:
if separator in arg:
return separator
return None
# Add variables to env.
# Assume that variables with 'PATH' in the name or that contain
# separators like ':' or ';' are more likely to be paths
for variable_name in new_variables:
sep = return_separator_if_any(after[variable_name])
if sep:
env.prepend_path(variable_name, after[variable_name], separator=sep)
elif "PATH" in variable_name:
env.prepend_path(variable_name, after[variable_name])
else:
# We just need to set the variable to the new value
env.set(variable_name, after[variable_name])
for variable_name in unset_variables:
env.unset(variable_name)
for variable_name in modified_variables:
value_before = before[variable_name]
value_after = after[variable_name]
sep = return_separator_if_any(value_before, value_after)
if sep:
before_list = value_before.split(sep)
after_list = value_after.split(sep)
# Filter out empty strings
before_list = list(filter(None, before_list))
after_list = list(filter(None, after_list))
# Remove duplicate entries (worse matching, bloats env)
if clean:
before_list = list(dedupe(before_list))
after_list = list(dedupe(after_list))
# The reassembled cleaned entries
value_before = sep.join(before_list)
value_after = sep.join(after_list)
# Paths that have been removed
remove_list = [ii for ii in before_list if ii not in after_list]
# Check that nothing has been added in the middle of
# before_list
remaining_list = [ii for ii in before_list if ii in after_list]
try:
start = after_list.index(remaining_list[0])
end = after_list.index(remaining_list[-1])
search = sep.join(after_list[start : end + 1])
except IndexError:
env.prepend_path(variable_name, value_after)
continue
if search not in value_before:
# We just need to set the variable to the new value
env.prepend_path(variable_name, value_after)
else:
try:
prepend_list = after_list[:start]
prepend_list.reverse() # Preserve order after prepend
except KeyError:
prepend_list = []
try:
append_list = after_list[end + 1 :]
except KeyError:
append_list = []
for item in remove_list:
env.remove_path(variable_name, item)
for item in append_list:
env.append_path(variable_name, item)
for item in prepend_list:
env.prepend_path(variable_name, item)
else:
# We just need to set the variable to the new value
env.set(variable_name, value_after)
return env
def _set_or_unset_not_first(
variable: str, changes: ModificationList, errstream: Callable[[str], None]
):
"""Check if we are going to set or unset something after other
modifications have already been requested.
"""
indexes = [
ii
for ii, item in enumerate(changes)
if ii != 0 and isinstance(item, (SetEnv, UnsetEnv)) and not getattr(item, "force", False)
]
if indexes:
good = "\t \t{}"
nogood = "\t--->\t{}"
errstream(f"Different requests to set/unset '{variable}' have been found")
for idx, item in enumerate(changes):
print_format = nogood if idx in indexes else good
errstream(print_format.format(item.trace))
[docs]
def validate(env: EnvironmentModifications, errstream: Callable[[str], None]):
"""Validates the environment modifications to check for the presence of
suspicious patterns. Prompts a warning for everything that was found.
Current checks:
- set or unset variables after other changes on the same variable
Args:
env: list of environment modifications
errstream: callable to log error messages
"""
if not env.traced:
return
modifications = env.group_by_name()
for variable, list_of_changes in sorted(modifications.items()):
_set_or_unset_not_first(variable, list_of_changes, errstream)
[docs]
def inspect_path(
root: Path,
inspections: MutableMapping[str, List[str]],
exclude: Optional[Callable[[Path], bool]] = None,
) -> EnvironmentModifications:
"""Inspects ``root`` to search for the subdirectories in ``inspections``.
Adds every path found to a list of prepend-path commands and returns it.
Args:
root: absolute path where to search for subdirectories
inspections: maps relative paths to a list of environment
variables that will be modified if the path exists. The
modifications are not performed immediately, but stored in a
command object that is returned to client
exclude: optional callable. If present it must accept an
absolute path and return True if it should be excluded from the
inspection
Examples:
The following lines execute an inspection in ``/usr`` to search for
``/usr/include`` and ``/usr/lib64``. If found we want to prepend
``/usr/include`` to ``CPATH`` and ``/usr/lib64`` to ``MY_LIB64_PATH``.
.. code-block:: python
# Set up the dictionary containing the inspection
inspections = {
'include': ['CPATH'],
'lib64': ['MY_LIB64_PATH']
}
# Get back the list of command needed to modify the environment
env = inspect_path('/usr', inspections)
# Eventually execute the commands
env.apply_modifications()
"""
if exclude is None:
exclude = lambda x: False
env = EnvironmentModifications()
# Inspect the prefix to check for the existence of common directories
for relative_path, variables in inspections.items():
expected = os.path.join(root, os.path.normpath(relative_path))
if os.path.isdir(expected) and not exclude(expected):
for variable in variables:
env.prepend_path(variable, expected)
return env
[docs]
@contextlib.contextmanager
def preserve_environment(*variables: str):
"""Ensures that the value of the environment variables passed as
arguments is the same before entering to the context manager and after
exiting it.
Variables that are unset before entering the context manager will be
explicitly unset on exit.
Args:
variables: list of environment variables to be preserved
"""
cache = {}
for var in variables:
# The environment variable to be preserved might not be there.
# In that case store None as a placeholder.
cache[var] = os.environ.get(var, None)
yield
for var in variables:
value = cache[var]
msg = "[PRESERVE_ENVIRONMENT]"
if value is not None:
# Print a debug statement if the value changed
if var not in os.environ:
msg += ' {0} was unset, will be reset to "{1}"'
tty.debug(msg.format(var, value))
elif os.environ[var] != value:
msg += ' {0} was set to "{1}", will be reset to "{2}"'
tty.debug(msg.format(var, os.environ[var], value))
os.environ[var] = value
elif var in os.environ:
msg += ' {0} was set to "{1}", will be unset'
tty.debug(msg.format(var, os.environ[var]))
del os.environ[var]
[docs]
def environment_after_sourcing_files(
*files: Union[Path, Tuple[str, ...]], **kwargs
) -> Dict[str, str]:
"""Returns a dictionary with the environment that one would have
after sourcing the files passed as argument.
Args:
*files: each item can either be a string containing the path
of the file to be sourced or a sequence, where the first element
is the file to be sourced and the remaining are arguments to be
passed to the command line
Keyword Args:
env (dict): the initial environment (default: current environment)
shell (str): the shell to use (default: ``/bin/bash`` or ``cmd.exe`` (Windows))
shell_options (str): options passed to the shell (default: ``-c`` or ``/C`` (Windows))
source_command (str): the command to run (default: ``source``)
suppress_output (str): redirect used to suppress output of command
(default: ``&> /dev/null``)
concatenate_on_success (str): operator used to execute a command
only when the previous command succeeds (default: ``&&``)
"""
# Set the shell executable that will be used to source files
if sys.platform == "win32":
shell_cmd = kwargs.get("shell", "cmd.exe")
shell_options = kwargs.get("shell_options", "/C")
suppress_output = kwargs.get("suppress_output", "")
source_command = kwargs.get("source_command", "")
else:
shell_cmd = kwargs.get("shell", "/bin/bash")
shell_options = kwargs.get("shell_options", "-c")
suppress_output = kwargs.get("suppress_output", "&> /dev/null")
source_command = kwargs.get("source_command", "source")
concatenate_on_success = kwargs.get("concatenate_on_success", "&&")
shell = Executable(shell_cmd)
def _source_single_file(file_and_args, environment):
shell_options_list = shell_options.split()
source_file = [source_command]
source_file.extend(x for x in file_and_args)
source_file = " ".join(source_file)
# If the environment contains 'python' use it, if not
# go with sys.executable. Below we just need a working
# Python interpreter, not necessarily sys.executable.
python_cmd = which("python3", "python", "python2")
python_cmd = python_cmd.path if python_cmd else sys.executable
dump_cmd = "import os, json; print(json.dumps(dict(os.environ)))"
dump_environment_cmd = python_cmd + f' -E -c "{dump_cmd}"'
# Try to source the file
source_file_arguments = " ".join(
[source_file, suppress_output, concatenate_on_success, dump_environment_cmd]
)
output = shell(
*shell_options_list,
source_file_arguments,
output=str,
env=environment,
ignore_quotes=True,
)
return json.loads(output)
current_environment = kwargs.get("env", dict(os.environ))
for file in files:
# Normalize the input to the helper function
if isinstance(file, str):
file = (file,)
current_environment = _source_single_file(file, environment=current_environment)
return current_environment
[docs]
def sanitize(
environment: MutableMapping[str, str], exclude: List[str], include: List[str]
) -> Dict[str, str]:
"""Returns a copy of the input dictionary where all the keys that
match an excluded pattern and don't match an included pattern are
removed.
Args:
environment (dict): input dictionary
exclude (list): literals or regex patterns to be excluded
include (list): literals or regex patterns to be included
"""
def set_intersection(fullset, *args):
# A set intersection using string literals and regexs
meta = "[" + re.escape("[$()*?[]^{|}") + "]"
subset = fullset & set(args) # As literal
for name in args:
if re.search(meta, name):
pattern = re.compile(name)
for k in fullset:
if re.match(pattern, k):
subset.add(k)
return subset
# Don't modify input, make a copy instead
environment = dict(environment)
# include supersedes any excluded items
prune = set_intersection(set(environment), *exclude)
prune -= set_intersection(prune, *include)
for k in prune:
environment.pop(k, None)
return environment