import sys, socket, select, gadfly
from gfsocket import reply_exception,reply_success,Packet_Reader,certify
# general error
ServerError = "ServerError"
# no such prepared name
PreparedNameError = "PreparedNameError"
# actions
# shut down the server (admin policy only)
# arguments = ()
# shutdown the server with no checkpoint
SHUTDOWN = "SHUTDOWN"
# restart the server (admin only)
# arguments = ()
# restart the server (recover)
# no checkpoint
RESTART = "RESTART"
# checkpoint the server (admin only)
# arguments = ()
# checkpoint the server
CHECKPOINT = "CHECKPOINT"
# exec prepared statement
# arguments = (prepared_name_string, dyn=None)
# execute the prepared statement with dynamic args.
# autocommit.
EXECUTE_PREPARED = "EXECUTE_PREPARED"
# exec any statement (only if not disabled)
# arguments = (statement_string, dyn=None)
# execute the statement with dynamic args.
# autocommit.
EXECUTE_STATEMENT = "EXECUTE_STATEMENT"
ACTIONS = [SHUTDOWN, RESTART, CHECKPOINT,
EXECUTE_PREPARED, EXECUTE_STATEMENT]
class Server:
"""database server: listen for commands"""
verbose = 1
# wait X minutes on each server loop
select_timeout = 60*5
# do a checkpoint each X times thru server loop
check_loop = 5
# for now works like finger/http
# == each command is a separate connection.
# all sql commands constitute separate transactions
# which are automatically committed upon success.
# for now commands come in as
# 1 length (marshalled int)
# 2 (password, data) (marshalled tuple)
# responses come back as
# 1 length (marshalled int)
# 2 results (marshalled value)
def __init__(self, port, db, dr, pw, startup=None):
self.port = port
self.db = db
self.dr = dr
self.pw = pw
self.startup = startup
self.connection = None
self.socket = None
# prepared cursors dictionary.
self.cursors = {}
self.policies = {}
self.admin_policy = None
def start(self):
"""after init, listen for commands."""
from gfsocket import READY,ERROR,unpack_certified_data
verbose = self.verbose
socket = self.socket
connection = self.connection
policies = self.policies
admin_policy = self.admin_policy
pending_connects = {}
while 1:
try:
# main loop
if self.check_loop < 0:
self.check_loop=5
for i in xrange(self.check_loop):
if verbose:
print "main loop on", socket, connection
# checkpoint loop
sockets = [socket]
if pending_connects:
sockets = sockets + pending_connects.keys()
# wait for availability
if verbose:
print "server: waiting for connection(s)"
(readables, dummy, errors) = select.select(\
sockets, [], sockets[:], self.select_timeout)
if socket in errors:
raise ServerError, \
"listening socket in error state: aborting"
# clean up error connection sockets
for s in errors:
del pending_connects[s]
s.close()
# get a new connection, if available
if socket in readables:
readables.remove(socket)
(conn, addr) = socket.accept()
if 1 or verbose:
print "connect %s" % (addr,)
reader = Packet_Reader(conn)
pending_connects[conn] = reader
# poll readable pending connections, if possible
for conn in readables:
reader = pending_connects[conn]
mode = reader.mode
if not mode==READY:
if mode == ERROR:
# shouldn't happen
try:
conn.close()
del pending_connects[conn]
except: pass
continue
else:
try:
reader.poll()
finally:
pass # AFTER DEBUG CHANGE THIS!
# in blocking mode, service ready request,
# commit on no error
for conn in pending_connects.keys():
reader = pending_connects[conn]
mode = reader.mode
if mode == ERROR:
try:
del pending_connects[conn]
conn.close()
except: pass
elif mode == READY:
try:
del pending_connects[conn]
data = reader.data
(actor_name, cert, md) = \
unpack_certified_data(data)
# find the policy for this actor
if not policies.has_key(actor_name):
if verbose:
print "no such policy: "+actor_name
reply_exception(NameError,
"no such policy: "+actor_name, conn)
policy = None
else:
if verbose:
print "executing for", actor_name
policy = policies[actor_name]
policy.action(cert, md, conn)
except SHUTDOWN:
if policy is admin_policy:
print \
"shutdown on admin policy: terminating"
connection.close()
socket.close()
# NORMAL TERMINATION:
return
except RESTART:
if policy is admin_policy:
print \
"restart from admin policy: restarting connection"
connection.restart()
except CHECKPOINT:
if policy is admin_policy:
print \
"checkpoint from admin policy: checkpointing now."
connection.checkpoint()
except:
tb = sys.exc_traceback
info = "%s %s" % (sys.exc_type,
str(sys.exc_value))
if verbose:
from traceback import print_tb
print_tb(tb)
print "error in executing action: "+info
reply_exception(
ServerError, "exception: "+info, conn)
#break # stop after first request serviced!
except:
# except of main while 1 try statement
tb = sys.exc_traceback
ty = sys.exc_type
va = sys.exc_value
print "UNEXPECTED EXCEPTION ON MAINLOOP"
from traceback import print_tb
print_tb(tb)
print "exception:", ty, va
if not pending_connects:
pending_connects = {}
print "server: checkpointing"
connection.checkpoint()
def init(self):
self.getconnection()
self.startup_load()
# get socket last in case of failure earlier
self.getsocket()
HOST = ""
BACKLOG = 5
def getsocket(self):
"""get the listening socket"""
verbose = self.verbose
import socket, sys
if verbose:
print "initializing listener socket"
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
try:
if verbose:
print "trying to set REUSEADDR",\
sock.getsockopt(socket.SOL_SOCKET,
socket.SO_REUSEADDR)
sock.setsockopt(socket.SOL_SOCKET,
socket.SO_REUSEADDR, 1)
except:
if verbose:
print "set of REUSEADDR failed", sys.exc_type, sys.exc_value
pass
sock.bind((self.HOST, self.port))
sock.listen(self.BACKLOG)
self.socket = sock
return sock
def getconnection(self):
"""get the db connection"""
from gadfly import gadfly
c = self.connection = gadfly(self.db, self.dr)
# don't automatically checkpoint upon commit
c.autocheckpoint = 0
def startup_load(self):
"""setup the policies and load startup module"""
admin_policy = self.get_admin_policy()
module_name = self.startup
if module_name:
module = __import__(module_name)
# startup(admin_policy, connection, Server_instance)
test = module.startup(admin_policy, self.connection, self)
if test is not None:
self.policies = test
self.policies["admin"] = admin_policy
def get_admin_policy(self):
"""return the admin policy for priviledged access."""
p = self.admin_policy = Policy(
"admin", self.pw, self.connection, queries=1)
return p
class Policy:
"""security policy"""
verbose = 0
# allow arbitrary sql statments
general_queries = 0
# dictionary of named accesses as strings
named_accesses = None
# dictionary of prepared named accesses
prepared_cursors = None
def __init__(self, name, password, connection, queries=0):
"""create a policy (name, password, connection)
name is the name of the policy
password is the access policy (None for no password)
connection is the database connection.
set queries to allow general accesses (unrestricted)
"""
if self.verbose:
print "policy.__init__", name
self.general_queries = queries
self.name = name
self.password = password
self.connection = connection
self.socket = None
self.named_accesses = {}
self.prepared_cursors = {}
def __setitem__(self, name, value):
if self.verbose:
print "policy", self.name, ":", (name, value)
from types import StringType
if type(name) is not StringType or type(value) is not StringType:
raise ValueError, "cursor names and contents must be strings"
self.named_accesses[name] = value
def execute_named(self, name, params=None):
"""execute a named (prepared) sql statement"""
if self.verbose:
print "policy", self.name, "executes", name, params
na = self.named_accesses
pc = self.prepared_cursors
con = self.connection
if not na.has_key(name):
raise PreparedNameError, "unknown access name: %s" % name
stat = na[name]
if pc.has_key(name):
# get prepared query
cursor = pc[name]
else:
# prepare a new cursor
pc[name] = cursor = con.cursor()
return self.execute(cursor, stat, params)
def execute(self, cursor, statement, params=None):
"""execute a statement in a cursor"""
if self.verbose:
print "policy", self.name, "executes", statement, params
cursor.execute(statement, params)
# immediate commit!
self.connection.commit()
try:
result = cursor.fetchall()
description = cursor.description
result = (description, result)
except:
result = None
return result
def execute_any_statement(self, statement, params=None):
"""execute any statement."""
if self.verbose:
print "policy", self.name, "executes", statement, params
con = self.connection
cursor = con.cursor()
return self.execute(cursor, statement, params)
def action(self, certificate, datastring, socket):
"""perform a database/server action after checking certificate"""
verbose = self.verbose
if verbose:
print "policy", self.name, "action..."
# make sure the certificate checks out
if not self.certify(datastring, certificate, self.password):
raise ServerError, "password certification failure"
# unpack the datastring
from marshal import loads
test = loads(datastring)
#if verbose:
#print "data is", test
(action, moredata) = test
import sys
if action in ACTIONS:
action = "policy_"+action
myaction = getattr(self, action)
try:
data = apply(myaction, moredata+(socket,))
#self.reply_success(data)
# pass up server level requests as exceptions
except SHUTDOWN, detail:
raise SHUTDOWN, detail
except RESTART, detail:
raise RESTART, detail
except CHECKPOINT, detail:
raise CHECKPOINT, detail
except:
tb = sys.exc_traceback
exceptiondata = "%s\n%s" %(sys.exc_type,
str(sys.exc_value))
if verbose:
from traceback import print_tb
print_tb(tb)
self.reply_exception(ServerError,
"unexpected exception: "+exceptiondata, socket)
raise ServerError, exceptiondata
else:
raise ServerError, "unknown action: "+`action`
def certify(self, datastring, certificate, password):
# hook for subclassing
return certify(datastring, certificate, password)
def policy_SHUTDOWN(self, socket):
self.reply_success("attempting server shutdown", socket)
raise SHUTDOWN, "please shut down the server"
def policy_RESTART(self, socket):
self.reply_success("attempting server restart", socket)
raise RESTART, "please restart the server"
def policy_CHECKPOINT(self, socket):
self.reply_success("attempting server checkpoint", socket)
raise CHECKPOINT, "please checkpoint the server"
def policy_EXECUTE_PREPARED(self, name, dyn, socket):
try:
result = self.execute_named(name, dyn)
self.reply_success(result, socket)
except PreparedNameError, detail:
self.reply_exception(PreparedNameError,
"no such prepared statement: "+name,
socket)
def policy_EXECUTE_STATEMENT(self, stat, dyn, socket):
if not self.general_queries:
self.reply_exception(ServerError,
"general statements disallowed on this policy",
socket)
raise ServerError, "illegal statement attempt for: "+self.name
result = self.execute_any_statement(stat, dyn)
self.reply_success(result, socket)
def reply_exception(self, exc, info, socket):
# hook for subclassing
reply_exception(exc, info, socket)
def reply_success(self, data, socket):
# hook for subclassing
reply_success(data, socket)
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