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# Copyright 2009 Canonical Ltd.
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# This file is part of desktopcouch.
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# desktopcouch is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Lesser General Public License version 3
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# as published by the Free Software Foundation.
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# desktopcouch is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Lesser General Public License for more details.
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# You should have received a copy of the GNU Lesser General Public License
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# along with desktopcouch. If not, see <http://www.gnu.org/licenses/>.
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"Desktop Couch helper files"
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from __future__ import with_statement
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import xdg.BaseDirectory
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from desktopcouch import local_files
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def process_is_couchdb_linux(pid):
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"""Find if the process with the given pid is couchdb."""
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pid = int(pid) # ensure it's a number
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proc_dir = "/proc/%d" % (pid,)
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# check to make sure it is actually a desktop-couch instance
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with open(os.path.join(proc_dir, 'cmdline')) as cmd_file:
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# make sure it's our process.
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if not os.access(os.path.join(proc_dir, "mem"), os.W_OK):
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os_name = platform.system()
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process_is_couchdb = {
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"Linux": process_is_couchdb_linux
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raise NotImplementedError("os %r is not yet supported" % (os_name,))
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def read_pidfile(ctx=local_files.DEFAULT_CONTEXT):
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"""Read the pid file for the required information."""
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pid_file = ctx.file_pid
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if not os.path.exists(pid_file):
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with open(pid_file) as fp:
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return None # not yet written to pid file
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logging.warn("Pid file does not contain int: %r", contents)
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logging.warn("Reading pid file caused error. %s", e)
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def find_pid(start_if_not_running=True, ctx=local_files.DEFAULT_CONTEXT):
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"""Find the current OS process ID of the running couchdb. API users
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should not use this, and instead go straight to find_port() ."""
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# Work out whether CouchDB is running by looking at its pid file
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pid = read_pidfile(ctx=ctx)
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if not process_is_couchdb(pid):
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if start_if_not_running:
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# start CouchDB by running the startup script
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logging.info("Desktop CouchDB is not running; starting it.")
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from desktopcouch import start_local_couchdb
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pid = start_local_couchdb.start_couchdb(ctx=ctx)
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# now load the design documents and pair records updates,
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# because it's started
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start_local_couchdb.update_design_documents()
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start_local_couchdb.update_pairing_service()
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if not process_is_couchdb(pid):
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logging.error("CouchDB process did not start up")
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raise RuntimeError("desktop-couch not started")
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def find_port(pid=None, ctx=local_files.DEFAULT_CONTEXT):
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"""Ask the service daemon through DBUS what the port is. This should start
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it up if it isn't running."""
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return _direct_access_find_port(pid=pid, ctx=ctx)
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#### This fails in multithreaded execution in the client, apparenly
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#### in DBus. Chad's guess is that there is some collision in getting
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#### a unique sequence ID for the asynchronous DBus method-call/
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#### method-response. Once that is worked out, resume using the
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#### rest of this function instead of the direct access above.
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# Hrm, we don't use 'pid' or 'ctx' any more, since we go through DBus.
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if ctx != local_files.DEFAULT_CONTEXT or pid is not None:
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return _direct_access_find_port(pid=pid, ctx=ctx)
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bus = dbus.SessionBus()
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proxy = bus.get_object('org.desktopcouch.CouchDB', '/')
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return proxy.getPort()
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def __find_port__linux(pid=None, ctx=local_files.DEFAULT_CONTEXT,
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"""This returns a valid port or raises a RuntimeError exception. It never
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returns anything else."""
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pid = find_pid(start_if_not_running=True, ctx=ctx)
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return __find_port__linux(pid, ctx, retries_left - 1)
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raise RuntimeError("Have no PID to use to look up port.")
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proc_dir = "/proc/%d" % (pid,)
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# enumerate the process' file descriptors
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fd_dir = os.path.join(proc_dir, 'fd')
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for dirent in os.listdir(fd_dir):
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dirent_path = os.path.join(fd_dir, dirent)
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fd_paths.append(os.readlink(dirent_path))
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logging.debug("dirent %r disappeared before " +
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"we could read it. ", dirent_path)
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return __find_port__linux(pid, ctx, retries_left - 1)
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logging.exception("Unable to find file descriptors in %s" % proc_dir)
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raise RuntimeError("Unable to find file descriptors in %s" % proc_dir)
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# identify socket fds
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socket_matches = [re.match('socket:\\[([0-9]+)\\]', p) for p in fd_paths]
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# extract their inode numbers
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socket_inodes = [m.group(1) for m in socket_matches if m is not None]
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# construct a subexpression which matches any one of these inodes
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inode_subexp = "|".join(map(re.escape, socket_inodes))
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# construct regexp to match /proc/net/tcp entries which are listening
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# sockets having one of the given inode numbers
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listening_regexp = re.compile(r'''
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[0-9A-F]{8}: # local_address part 1
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([0-9A-F]{4})\s+ # local_address part 2
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00000000:0000\s+ # rem_address
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0A\s+ # st (0A = listening)
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[0-9A-F]{8}: # tx_queue
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[0-9A-F]{8}\s+ # rx_queue
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[0-9A-F]{8}\s+ # tm->when
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[0-9A-F]{8}\s* # retrnsmt
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\d+\s+\d+\s+ # uid, timeout
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''' % (inode_subexp,), re.VERBOSE)
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# extract the TCP port from the first matching line in /proc/$pid/net/tcp
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with open(os.path.join(proc_dir, 'net', 'tcp')) as tcp_file:
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for line in tcp_file:
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match = listening_regexp.match(line)
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if match is not None:
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port = str(int(match.group(1), 16))
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return __find_port__linux(pid, ctx, retries_left - 1)
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raise RuntimeError("Unable to find listening port")
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os_name = platform.system()
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_direct_access_find_port = {
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"Linux": __find_port__linux
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logging.error("os %r is not yet supported" % (os_name,))
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raise NotImplementedError("os %r is not yet supported" % (os_name,))
added
removed
desktopcouch/__init__.py
