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# Copyright 2009 Canonical Ltd. This software is licensed under the
# GNU Affero General Public License version 3 (see the file LICENSE).
"""Implementation of the dynamic RewriteMap used to serve branches over HTTP.
"""
import time
from bzrlib import urlutils
from zope.component import getUtility
from canonical.config import config
from canonical.launchpad.webapp.adapter import (
clear_request_started,
set_request_started,
)
from lp.code.interfaces.branchlookup import IBranchLookup
from lp.code.interfaces.codehosting import BRANCH_ID_ALIAS_PREFIX
from lp.codehosting.vfs import branch_id_to_path
from lp.services.utils import iter_split
__all__ = ['BranchRewriter']
class BranchRewriter:
def __init__(self, logger, _now=None):
"""
:param logger: Logger that messages about what the rewriter is doing
will be sent to.
:param proxy: A blocking proxy for a branchfilesystem endpoint.
"""
if _now is None:
self._now = time.time
else:
self._now = _now
self.logger = logger
self._cache = {}
def _codebrowse_url(self, path):
return urlutils.join(
config.codehosting.internal_codebrowse_root,
path)
def _getBranchIdAndTrailingPath(self, location):
"""Return the branch id and trailing path for 'location'.
In addition this method returns whether the answer can from the cache
or from the database.
"""
for first, second in iter_split(location[1:], '/'):
if first in self._cache:
branch_id, inserted_time = self._cache[first]
if (self._now() < inserted_time +
config.codehosting.branch_rewrite_cache_lifetime):
return branch_id, '/' + second, "HIT"
branch_id, trailing = getUtility(IBranchLookup).getIdAndTrailingPath(
location, from_slave=True)
if branch_id is None:
return None, None, "MISS"
else:
unique_name = location[1:-len(trailing)]
self._cache[unique_name] = (branch_id, self._now())
return branch_id, trailing, "MISS"
def rewriteLine(self, resource_location):
"""Rewrite 'resource_location' to a more concrete location.
We use the 'translatePath' BranchFileSystemClient method. There are
three cases:
(1) The request is for something within the .bzr directory of a
branch.
In this case we rewrite the request to the location from which
branches are served by ID.
(2) The request is for something within a branch, but not the .bzr
directory.
In this case, we hand the request off to codebrowse.
(3) The branch is not found. Two sub-cases: the request is for a
product control directory or the we don't know how to translate
the path.
In both these cases we return 'NULL' which indicates to Apache
that we don't know how to rewrite the request (and so it should
go on to generate a 404 response).
Other errors are allowed to propagate, on the assumption that the
caller will catch and log them.
"""
# Codebrowse generates references to its images and stylesheets
# starting with "/static", so pass them on unthinkingly.
T = time.time()
# Tell the webapp adapter that we are in a request, so that DB
# statement timeouts will be applied.
set_request_started()
try:
cached = None
if resource_location.startswith('/static/'):
r = self._codebrowse_url(resource_location)
cached = 'N/A'
else:
branch_id, trailing, cached = self._getBranchIdAndTrailingPath(
resource_location)
if branch_id is None:
if resource_location.startswith('/' + BRANCH_ID_ALIAS_PREFIX):
r = 'NULL'
else:
r = self._codebrowse_url(resource_location)
else:
if trailing.startswith('/.bzr'):
r = urlutils.join(
config.codehosting.internal_branch_by_id_root,
branch_id_to_path(branch_id), trailing[1:])
else:
r = self._codebrowse_url(resource_location)
finally:
clear_request_started()
self.logger.info(
"%r -> %r (%fs, cache: %s)",
resource_location, r, time.time() - T, cached)
return r
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