Re: [Orbit-python-list] NameService howto?

[Christian Robottom Reis <kiko async com br>]

On Thu, 17 May 2001, Frank Rehberger wrote:

> I dont understand how to connect to the nameservice of orbit.
> The following shows my code:

I assume here that you are running orbit-name-server, included in the
ORBit distro, yes?

> orb  = CORBA.ORB_init(sys.argv, CORBA.ORB_ID)
> poa  = orb.resolve_initial_references("RootPOA")
> service = orb.resolve_initial_references("NameService")

Ah, your error lies here, and I'd like Tack to comment if he may.
Look, every CORBA-ized object publishes an object reference for itself. If
you have noticed, when you run o-n-s, it prints to stdout it's own IOR.

Now I think the standard facility for retrieving this is from etc/orbitrc
or ~/.orbitrc. Which means AFAICS that if you run the NameService, you
have to paste the IOR into that file. I know of no other way to do it, but
perhaps Eliott or somebody from orbit can help.

This is a definite problem, since you'll be running the nameservice with
interruptions, possible, which means you'll have to update the file in
realtime. I avoid doing that completely by going an orthogonal way: I
catch the nameserver reference from o-n-s and:

a) store it in a file in an nfs-shared directory, where clients can catch
it.

b) publish the reference through a webserver or whatever other means. I
personally created a tiny socket server and client that just spits the IOR
over.

Now my personal opinion is that's just plain annoying. But CORBA -- not
ORBit, I think, put perhaps it lacks a service (from what I grasp of it)
provides no standard mechanism to bootstrap the IOR, and that's evil. And
since GNOME publishes IOR in another fashion (using xprops, I think) it
doesn't bother them enough to implement some standard workaround :-)

> I would like to list the nameservice content.
> Who can help me?

I used to have some clients but I seem to have lost them. I'm attaching
the evil solution I use, so you can check it out. Please comment out the
part referring to the configfile as I don't really want to hack this right
now :-)

Take care,
--
/\/\ Christian Reis, Senior Engineer, Async Open Source, Brazil
~\/~ http://async.com.br/~kiko/ | [+55 16] 274 4311

#!/usr/bin/env python
import socket, ConfigParser,sys 

# FIXME: comes from ConfigFile
DEFAULT_HOST='localhost'
DEFAULT_PORT=3733
RCFILE="/usr/local/stoq/serverrc"

cp=ConfigParser.ConfigParser()
cp.read(RCFILE)
if cp.has_section("NameService"):
	PORT=int(cp.get("NameService","NS_PORT"))
	HOST=cp.get("NameService","NS_HOST")
	print "From rcfile read port %d on host %s" % (PORT, HOST)
else:
	print "Using default port %d" % DEFAULT_PORT
	PORT=DEFAULT_PORT
	HOST=DEFAULT_HOST

try:
	s=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
	s.connect((HOST,PORT))
except:
	print "Server not running on port %d of host %s" % (PORT,HOST)
	sys.exit()

iorstring=s.recv(4096)
s.close()

#print "The Nameserver's IOR is: \n\n"+iorstring
print "IOR: %s" % iorstring,

#!/usr/local/bin/python
import socket, signal, sys, os, getopt, string

# Stoq nameserver IOR spitter v0.0 
# Born 22 Nov 2K kiko async com br

# The DEFAULT_PORT is only used if the rcfile can't be read
# DEFAULT_HOST is useless, IMO

DEFAULT_PORT=3733
DEFAULT_HOST=""
DEBUG=0

def appkill(signum, frame):
	print "%s: shutting down" % sys.argv[0]
	sys.exit()

signal.signal(signal.SIGTERM,appkill)
signal.signal(signal.SIGINT,appkill)

PORT=DEFAULT_PORT
HOST=DEFAULT_HOST

try:
	opt, args = getopt.getopt(sys.argv[1:],'p:h', ['help','port='] )
except getopt.error, s:
	print "%s: %s" % (sys.argv[0] , s)
	sys.exit(1)

for o in opt:

	if o[0] == "-d" or o[0] == "--debug":
		DEBUG=1

	if o[0] == "-p" or o[0] == "--port":
		try:
			PORT=int(o[1])
		except ValueError:
			print "%s: port number must be integer" % sys.argv[0]
			sys.exit(1)

	if o[0] == "-h" or o[0] == "--help":
		print "%s: CORBA Nameserver Wrapper (with TCP-spit IOR)" % sys.argv[0]
		print "%s: usage: %s [-p port]" % ( sys.argv[0] , sys.argv[0] )
		sys.exit(1)

try:
	s=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
		# to avoid being stuck with sockets in TIME_WAIT
	s.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)
	s.bind(HOST,PORT)
	s.listen(1)
except:
	s.close()
	print 'Problem with socket creation and bind'
	print sys.exc_type,sys.exc_value
	sys.exit(1)

# inverted exception handling here - found is good, default is bad

try: 
	for f in string.split(os.environ["PATH"],":"):
		if os.access( "%s/orbit-name-server" % f,os.X_OK):
			raise "Found"
	print "%s: orbit-name-server not found in path" % sys.argv[0]
	sys.exit(1)
except "Found":
	pass

# This is a bit of black magic but it works for me: we popen
# orbit-name-server, read the ior and f.close() it. Now, since this
# child process is mine, it dies when I sys.exit(), and we're all happy.
# Looks unlikely to work on Win32, but os.popen doesn't work anyway :-)
f=os.popen("orbit-name-server &","r")
iorstring=f.readline()
f.close()

if DEBUG:
	print "IOR is %s" % iorstring
if DEBUG:
	print "%s: started up with port to %s" % ( sys.argv[0] , PORT )

try:
	while 1:
		conn,addr=s.accept()
		if DEBUG:
			print 'Peer is',addr
		conn.send(iorstring)
		conn.close()
except SystemExit:
	sys.exit(0)
except:
	conn.close()
	s.close()
	print 'Foobared'
	print sys.exc_type,sys.exc_value
	sys.exit(1)