Commit ae6206fe authored by Maurits van Rees's avatar Maurits van Rees

Do not remove an existing egg.

When installing an egg to a location that already exists, keep the
current location (directory or file).

This can only happen when the location at first did not exist and this
changed during the buildout run.  We used to remove the previous
location, but this could cause problems when running two buildouts at
the same time, when they try to install the same new egg.

Fixes #307.
parent 5040cae3
...@@ -4,6 +4,14 @@ Change History ...@@ -4,6 +4,14 @@ Change History
2.5.3 (unreleased) 2.5.3 (unreleased)
================== ==================
- Do not remove an existing egg. When installing an egg to a location
that already exists, keep the current location (directory or file).
This can only happen when the location at first did not exist and
this changed during the buildout run. We used to remove the
previous location, but this could cause problems when running two
buildouts at the same time, when they try to install the same new
egg. Fixes #307. [maurits]
- In ``zc.buildout.testing.system``, set ``TERM=dumb`` in the environment. - In ``zc.buildout.testing.system``, set ``TERM=dumb`` in the environment.
This avoids invisible control characters popping up in some terminals, This avoids invisible control characters popping up in some terminals,
like ``xterm``. Note that this may affect tests by buildout recipes. like ``xterm``. Note that this may affect tests by buildout recipes.
......
...@@ -397,16 +397,8 @@ class Installer: ...@@ -397,16 +397,8 @@ class Installer:
result = [] result = []
for d in dists: for d in dists:
newloc = os.path.join(dest, os.path.basename(d.location)) newloc = _move_to_eggs_dir(d, dest)
if os.path.exists(newloc):
if os.path.isdir(newloc):
shutil.rmtree(newloc)
else:
os.remove(newloc)
os.rename(d.location, newloc)
[d] = pkg_resources.Environment([newloc])[d.project_name] [d] = pkg_resources.Environment([newloc])[d.project_name]
result.append(d) result.append(d)
return result return result
...@@ -526,18 +518,7 @@ class Installer: ...@@ -526,18 +518,7 @@ class Installer:
if dist.precedence == pkg_resources.EGG_DIST: if dist.precedence == pkg_resources.EGG_DIST:
# It's already an egg, just fetch it into the dest # It's already an egg, just fetch it into the dest
newloc = _move_to_eggs_dir(dist, self._dest)
newloc = os.path.join(
self._dest, os.path.basename(dist.location))
if os.path.isdir(dist.location):
# we got a directory. It must have been
# obtained locally. Just copy it.
shutil.copytree(dist.location, newloc)
else:
setuptools.archive_util.unpack_archive(
dist.location, newloc)
redo_pyc(newloc) redo_pyc(newloc)
# Getting the dist from the environment causes the # Getting the dist from the environment causes the
...@@ -1564,3 +1545,66 @@ class IncompatibleConstraintError(zc.buildout.UserError): ...@@ -1564,3 +1545,66 @@ class IncompatibleConstraintError(zc.buildout.UserError):
""" """
IncompatibleVersionError = IncompatibleConstraintError # Backward compatibility IncompatibleVersionError = IncompatibleConstraintError # Backward compatibility
def _move_to_eggs_dir(dist, dest):
"""Move distribution to the eggs destination directory.
Its new location is expected not to exist there yet, otherwise we
would not be calling this function: the egg is already there. But
the new location might exist at this point if another buildout is
running in parallel. So we copy to a temporary directory first.
See discussion at https://github.com/buildout/buildout/issues/307
We return the new location.
"""
# First make sure the destination directory exists. This could suffer from
# the same kind of race condition as the rest: if we check that it does not
# exist, and we then create it, it will fail when a second buildout is
# doing the same thing.
try:
os.makedirs(dest)
except OSError:
if not os.path.isdir(dest):
# Unknown reason. Reraise original error.
raise
newloc = os.path.join(
dest, os.path.basename(dist.location))
tmp_dest = tempfile.mkdtemp(dir=dest)
try:
tmp_egg_dir = os.path.join(tmp_dest, os.path.basename(dist.location))
if os.path.isdir(dist.location):
# We got a directory. It must have been obtained locally.
# Just copy it.
shutil.copytree(dist.location, tmp_egg_dir)
else:
# It is a zipped egg. Buildout 2 no longer installs zipped eggs,
# so we always want to unpack it.
setuptools.archive_util.unpack_archive(
dist.location, tmp_egg_dir)
# We have copied the egg. Now try to rename/move it.
try:
os.rename(tmp_egg_dir, newloc)
except OSError:
# Might be for various reasons. If it is because newloc already
# exists, we can investigate.
if not os.path.exists(newloc):
# No, it is a different reason. Give up.
raise
# Try to use it as environment and check if our project is in it.
if not pkg_resources.Environment([newloc])[dist.project_name]:
# Path exists, but is not our package. We could
# try something, but it seems safer to bail out
# with the original error.
raise
# newloc looks okay to use. Do print a warning.
logger.warn(
"Path %s unexpectedly already exists.\n"
"Maybe a buildout running in parallel has added it. "
"We will accept it.\n"
"If this contains a wrong package, please remove it yourself.",
newloc)
finally:
# Remember that temporary directories must be removed
shutil.rmtree(tmp_dest)
return newloc
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