Introduce dynamic scope_path regexps
Instead of relying on scope_path's being "one slash deep", we should
instead allow for either:
1. scope_paths that have a pre-defined depth
2. scope_paths that can be arbitrarily deep
We achieve 1 by setting an entities scope_logic to another logic
module. We then recursively call getScopeDepth until we get to the
topmost entity (that is, an unscoped entity).
A little different is the solution to 2, since some entities can have
an arbitrarily deep scope (such as Documents), we need to have some
way of signaling this to getScopePattern. A clean solution is to
return None, rather than a number. If None is returned, the
SCOPE_PATH_ARG_PATTERN is returned as regexp instead, which will
match an arbitrarily deeply nested scope.
The solution for 2 requires that we return None somewhere in the
scope_logic chain, the most straight forward method to do so is to
override getScopeDepth anywhere such a scope is needed and make it
return None. A more elegant solution however, is to set the
scope_logic to that module in all entities that require it.
Patch by: Sverre Rabbelier
import os
import sys
if os.name == 'posix':
def become_daemon(our_home_dir='.', out_log='/dev/null',
err_log='/dev/null', umask=022):
"Robustly turn into a UNIX daemon, running in our_home_dir."
# First fork
try:
if os.fork() > 0:
sys.exit(0) # kill off parent
except OSError, e:
sys.stderr.write("fork #1 failed: (%d) %s\n" % (e.errno, e.strerror))
sys.exit(1)
os.setsid()
os.chdir(our_home_dir)
os.umask(umask)
# Second fork
try:
if os.fork() > 0:
os._exit(0)
except OSError, e:
sys.stderr.write("fork #2 failed: (%d) %s\n" % (e.errno, e.strerror))
os._exit(1)
si = open('/dev/null', 'r')
so = open(out_log, 'a+', 0)
se = open(err_log, 'a+', 0)
os.dup2(si.fileno(), sys.stdin.fileno())
os.dup2(so.fileno(), sys.stdout.fileno())
os.dup2(se.fileno(), sys.stderr.fileno())
# Set custom file descriptors so that they get proper buffering.
sys.stdout, sys.stderr = so, se
else:
def become_daemon(our_home_dir='.', out_log=None, err_log=None, umask=022):
"""
If we're not running under a POSIX system, just simulate the daemon
mode by doing redirections and directory changing.
"""
os.chdir(our_home_dir)
os.umask(umask)
sys.stdin.close()
sys.stdout.close()
sys.stderr.close()
if err_log:
sys.stderr = open(err_log, 'a', 0)
else:
sys.stderr = NullDevice()
if out_log:
sys.stdout = open(out_log, 'a', 0)
else:
sys.stdout = NullDevice()
class NullDevice:
"A writeable object that writes to nowhere -- like /dev/null."
def write(self, s):
pass