Viewing file:  req_tracker.py (4.58 KB) -rw-r--r--
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from __future__ import absolute_import
import contextlib
import errno
import hashlib
import logging
import os
from pip._vendor import contextlib2
from pip._internal.utils.temp_dir import TempDirectory
from pip._internal.utils.typing import MYPY_CHECK_RUNNING
if MYPY_CHECK_RUNNING:
from types import TracebackType
from typing import Dict, Iterator, Optional, Set, Type, Union
from pip._internal.req.req_install import InstallRequirement
from pip._internal.models.link import Link
logger = logging.getLogger(__name__)
@contextlib.contextmanager
def update_env_context_manager(**changes):
# type: (str) -> Iterator[None]
target = os.environ
# Save values from the target and change them.
non_existent_marker = object()
saved_values = {} # type: Dict[str, Union[object, str]]
for name, new_value in changes.items():
try:
saved_values[name] = target[name]
except KeyError:
saved_values[name] = non_existent_marker
target[name] = new_value
try:
yield
finally:
# Restore original values in the target.
for name, original_value in saved_values.items():
if original_value is non_existent_marker:
del target[name]
else:
assert isinstance(original_value, str) # for mypy
target[name] = original_value
@contextlib.contextmanager
def get_requirement_tracker():
# type: () -> Iterator[RequirementTracker]
root = os.environ.get('PIP_REQ_TRACKER')
with contextlib2.ExitStack() as ctx:
if root is None:
root = ctx.enter_context(
TempDirectory(kind='req-tracker')
).path
ctx.enter_context(update_env_context_manager(PIP_REQ_TRACKER=root))
logger.debug("Initialized build tracking at %s", root)
with RequirementTracker(root) as tracker:
yield tracker
class RequirementTracker(object):
def __init__(self, root):
# type: (str) -> None
self._root = root
self._entries = set() # type: Set[InstallRequirement]
logger.debug("Created build tracker: %s", self._root)
def __enter__(self):
# type: () -> RequirementTracker
logger.debug("Entered build tracker: %s", self._root)
return self
def __exit__(
self,
exc_type, # type: Optional[Type[BaseException]]
exc_val, # type: Optional[BaseException]
exc_tb # type: Optional[TracebackType]
):
# type: (...) -> None
self.cleanup()
def _entry_path(self, link):
# type: (Link) -> str
hashed = hashlib.sha224(link.url_without_fragment.encode()).hexdigest()
return os.path.join(self._root, hashed)
def add(self, req):
# type: (InstallRequirement) -> None
"""Add an InstallRequirement to build tracking.
"""
assert req.link
# Get the file to write information about this requirement.
entry_path = self._entry_path(req.link)
# Try reading from the file. If it exists and can be read from, a build
# is already in progress, so a LookupError is raised.
try:
with open(entry_path) as fp:
contents = fp.read()
except IOError as e:
# if the error is anything other than "file does not exist", raise.
if e.errno != errno.ENOENT:
raise
else:
message = '{} is already being built: {}'.format(
req.link, contents)
raise LookupError(message)
# If we're here, req should really not be building already.
assert req not in self._entries
# Start tracking this requirement.
with open(entry_path, 'w') as fp:
fp.write(str(req))
self._entries.add(req)
logger.debug('Added %s to build tracker %r', req, self._root)
def remove(self, req):
# type: (InstallRequirement) -> None
"""Remove an InstallRequirement from build tracking.
"""
assert req.link
# Delete the created file and the corresponding entries.
os.unlink(self._entry_path(req.link))
self._entries.remove(req)
logger.debug('Removed %s from build tracker %r', req, self._root)
def cleanup(self):
# type: () -> None
for req in set(self._entries):
self.remove(req)
logger.debug("Removed build tracker: %r", self._root)
@contextlib.contextmanager
def track(self, req):
# type: (InstallRequirement) -> Iterator[None]
self.add(req)
yield
self.remove(req)
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