procutil: make stream detection in make_line_buffered more correct and strict
In make_line_buffered(), we don’t want to wrap the stream if we know that lines
get flushed to the underlying raw stream already.
Previously, the heuristic was too optimistic. It assumed that any stream which
is not an instance of io.BufferedIOBase doesn’t need wrapping. However, there
are buffered streams that aren’t instances of io.BufferedIOBase, like
Mercurial’s own winstdout.
The new logic is different in two ways:
First, only for the check, if unwraps any combination of WriteAllWrapper and
winstdout.
Second, it skips wrapping the stream only if it is an instance of io.RawIOBase
(or already wrapped). If it is an instance of io.BufferedIOBase, it gets
wrapped. In any other case, the function raises an exception. This ensures
that, if an unknown stream is passed or we add another wrapper in the future,
we don’t wrap the stream if it’s already line buffered or not wrap the stream
if it’s not line buffered. In fact, this was already helpful during development
of this change. Without it, I possibly would have forgot that WriteAllWrapper
needs to be ignored for the check, leading to unnecessary wrapping if stdout is
unbuffered.
The alternative would have been to always wrap unknown streams. However, I
don’t think that anyone would benefit from being less strict. We can expect
streams from the standard library to be subclassing either io.RawIOBase or
io.BufferedIOBase, so running Mercurial in the standard way should not regress
by this change. Py2exe might replace sys.stdout and sys.stderr, but that
currently breaks Mercurial anyway and also these streams don’t claim to be
interactive, so this function is not called for them.
#!/bin/bash
# This script gets executed on container start. Its job is to set up
# the Mercurial environment and invoke the server.
# Mercurial can be started in two modes.
# If the MERCURIAL_SOURCE environment variable is set and it points to a
# Mercurial source directory, we will install Mercurial from that directory.
# Otherwise, we download the Mercurial source and install it manually.
set -e
SOURCE_DIR=/var/hg/source
INSTALL_DIR=/var/hg/install
REPOS_DIR=/var/hg/repos
HTDOCS_DIR=/var/hg/htdocs
if [ ! -d ${SOURCE_DIR} ]; then
echo "Mercurial source not available at ${SOURCE_DIR}"
echo "You need to mount a volume containing the Mercurial source code"
echo "when running the container. For example:"
echo ""
echo " $ docker run -v ~/src/hg:/${SOURCE_DIR} hg-apache"
echo ""
echo "This container will now stop running."
exit 1
fi
echo "Installing Mercurial from ${SOURCE_DIR} into ${INSTALL_DIR}"
pushd ${SOURCE_DIR}
/usr/bin/python2.7 setup.py install --root=/ --prefix=${INSTALL_DIR} --force
popd
mkdir -p ${HTDOCS_DIR}
# Provide a default config if the user hasn't supplied one.
if [ ! -f ${HTDOCS_DIR}/config ]; then
cp /defaulthgwebconfig ${HTDOCS_DIR}/config
fi
if [ ! -f ${HTDOCS_DIR}/hgweb.wsgi ]; then
cat >> ${HTDOCS_DIR}/hgweb.wsgi << EOF
config = '${HTDOCS_DIR}/config'
import sys
sys.path.insert(0, '${INSTALL_DIR}/lib/python2.7/site-packages')
from mercurial import demandimport
demandimport.enable()
from mercurial.hgweb import hgweb
application = hgweb(config)
EOF
fi
mkdir -p ${REPOS_DIR}
if [ ! -d ${REPOS_DIR}/repo ]; then
${INSTALL_DIR}/bin/hg init ${REPOS_DIR}/repo
chown -R www-data:www-data ${REPOS_DIR}/repo
fi
# This is necessary to make debuginstall happy.
if [ ! -f ~/.hgrc ]; then
cat >> ~/.hgrc << EOF
[ui]
username = Dummy User <nobody@example.com>
EOF
fi
echo "Verifying Mercurial installation looks happy"
${INSTALL_DIR}/bin/hg debuginstall
. /etc/apache2/envvars
echo "Starting Apache HTTP Server on port 80"
echo "We hope you remembered to publish this port when running the container!"
echo "If this is an interactive container, simply CTRL^C to stop."
exec "$@"