+"""Functionality common to all account classes.
+
+Each subclass of Account must provide five methods: create() and
+destroy(), which are static; configure(), start(), and stop(), which
+are not. configure(), which takes a record as its only argument, does
+things like set up ssh keys. In addition, an Account subclass must
+provide static member variables SHELL, which contains the unique shell
+that it uses; and TYPE, a string that is used by the account creation
+code. For no particular reason, TYPE is divided hierarchically by
+periods; at the moment the only convention is that all sliver accounts
+have type that begins with sliver.
+
+There are any number of race conditions that may result from the fact
+that account names are not unique over time. Moreover, it's a bad
+idea to perform lengthy operations while holding the database lock.
+In order to deal with both of these problems, we use a worker thread
+for each account name that ever exists. On 32-bit systems with large
+numbers of accounts, this may cause the NM process to run out of
+*virtual* memory! This problem may be remedied by decreasing the
+maximum stack size.
+"""
+
import Queue
import os
import pwd
import tools
+# When this variable is true, start after any ensure_created
+Startingup = False
+# Cumulative delay for starts when Startingup is true
+csd_lock = threading.Lock()
+cumstartdelay = 0
+
# shell path -> account class association
shell_acct_class = {}
# account type -> account class association
type_acct_class = {}
def register_class(acct_class):
- """Call once for each account class. This method adds the class to the dictionaries used to ook up account classes by shell and type."""
+ """Call once for each account class. This method adds the class to the dictionaries used to look up account classes by shell and type."""
shell_acct_class[acct_class.SHELL] = acct_class
type_acct_class[acct_class.TYPE] = acct_class
# private account name -> worker object association and associated lock
-_name_worker_lock = threading.Lock()
-_name_worker = {}
+name_worker_lock = threading.Lock()
+name_worker = {}
+
+def allpwents():
+ return [pw_ent for pw_ent in pwd.getpwall() if pw_ent[6] in shell_acct_class]
def all():
- """Returns a list of all NM accounts on the system. Format is (type, username)."""
- pw_ents = pwd.getpwall()
- for pw_ent in pw_ents:
- if pw_ent[6] in shell_acct_class:
- yield shell_acct_class[pw_ent[6]].TYPE, pw_ent[0]
+ """Return the names of all accounts on the system with recognized shells."""
+ return [pw_ent[0] for pw_ent in allpwents()]
def get(name):
"""Return the worker object for a particular username. If no such object exists, create it first."""
- _name_worker_lock.acquire()
+ name_worker_lock.acquire()
try:
- if name not in _name_worker: _name_worker[name] = Worker(name)
- return _name_worker[name]
- finally: _name_worker_lock.release()
-
-
-def install_ssh_keys(rec):
- """Write <rec['ssh_keys']> to <rec['name']>'s authorized_keys file."""
- dot_ssh = '/home/%s/.ssh' % rec['name']
- def do_installation():
- if not os.access(dot_ssh, os.F_OK): os.mkdir(dot_ssh)
- tools.write_file(dot_ssh + '/authorized_keys',
- lambda thefile: thefile.write(rec['ssh_keys']))
- logger.log('%s: installing ssh keys' % rec['name'])
- tools.fork_as(rec['name'], do_installation)
+ if name not in name_worker: name_worker[name] = Worker(name)
+ return name_worker[name]
+ finally: name_worker_lock.release()
+
+
+class Account:
+ def __init__(self, rec):
+ self.name = rec['name']
+ self.keys = ''
+ self.initscriptchanged = False
+ self.configure(rec)
+
+ @staticmethod
+ def create(name, vref = None): abstract
+ @staticmethod
+ def destroy(name): abstract
+
+ def configure(self, rec):
+ """Write <rec['keys']> to my authorized_keys file."""
+ new_keys = rec['keys']
+ if new_keys != self.keys:
+ self.keys = new_keys
+ dot_ssh = '/home/%s/.ssh' % self.name
+ def do_installation():
+ if not os.access(dot_ssh, os.F_OK): os.mkdir(dot_ssh)
+ os.chmod(dot_ssh, 0700)
+ tools.write_file(dot_ssh + '/authorized_keys', lambda f: f.write(new_keys))
+ logger.log('%s: installing ssh keys' % self.name)
+ tools.fork_as(self.name, do_installation)
+
+ def start(self, delay=0): pass
+ def stop(self): pass
class Worker:
_destroy_sem = threading.Semaphore(1)
def __init__(self, name):
- # username
- self.name = name
- # the account object currently associated with this worker
- self._acct = None
+ self.name = name # username
+ self._acct = None # the account object currently associated with this worker
# task list
# outsiders request operations by putting (fn, args...) tuples on _q
# the worker thread (created below) will perform these operations in order
tools.as_daemon_thread(self._run)
def ensure_created(self, rec):
- """Caused the account specified by <rec> to exist if it doesn't already."""
- self._q.put((self._ensure_created, tools.deepcopy(rec)))
+ """Cause the account specified by <rec> to exist if it doesn't already."""
+ self._q.put((self._ensure_created, rec.copy(), Startingup))
- def _ensure_created(self, rec):
+ def _ensure_created(self, rec, startingup):
curr_class = self._get_class()
- next_class = type_acct_class[rec['account_type']]
+ next_class = type_acct_class[rec['type']]
if next_class != curr_class:
self._destroy(curr_class)
self._create_sem.acquire()
- try: next_class.create(self.name)
+ try: next_class.create(self.name, rec['vref'])
finally: self._create_sem.release()
- self._make_acct_obj()
- self._acct.configure(rec)
- if next_class != curr_class: self._acct.start()
+ if not isinstance(self._acct, next_class): self._acct = next_class(rec)
+ else: self._acct.configure(rec)
+ if startingup:
+ csd_lock.acquire()
+ global cumstartdelay
+ delay = cumstartdelay
+ cumstartdelay += 2
+ csd_lock.release()
+ self._acct.start(delay=delay)
+ elif next_class != curr_class or self._acct.initscriptchanged:
+ self._acct.start()
def ensure_destroyed(self): self._q.put((self._ensure_destroyed,))
def _ensure_destroyed(self): self._destroy(self._get_class())
- def start(self): self._q.put((self._start,))
- def _start(self):
- self._make_acct_obj()
- self._acct.start()
+ def start(self, delay=0): self._q.put((self._start, delay))
+ def _start(self, d): self._acct.start(delay=d)
def stop(self): self._q.put((self._stop,))
- def _stop(self):
- self._make_acct_obj()
- self._acct.stop()
+ def _stop(self): self._acct.stop()
def _destroy(self, curr_class):
self._acct = None
except KeyError: return None
return shell_acct_class[shell]
- def _make_acct_obj(self):
- curr_class = self._get_class()
- if not isinstance(self._acct, curr_class):
- self._acct = curr_class(self.name)
-
def _run(self):
+ """Repeatedly pull commands off the queue and execute. If memory usage becomes an issue, it might be wise to terminate after a while."""
while True:
try:
cmd = self._q.get()
cmd[0](*cmd[1:])
- except: logger.log_exc()
+ except:
+ logger.log_exc(self.name)
git://git.onelab.eu / nodemanager.git / blobdiff