Factored out a lot of common code.

[software/pymin.git] / services / dhcp / __init__.py

diff --git a/services/dhcp/__init__.py b/services/dhcp/__init__.py
index 941bccf0924df9388fce7672211013e63f80c659..7ffadcf7a4dc424a421bb6d77fc2b71d8df8f76e 100644 (file)
--- a/services/dhcp/__init__.py
+++ b/services/dhcp/__init__.py
@@ -1,125 +1,263 @@
 # vim: set encoding=utf-8 et sw=4 sts=4 :
 
 # vim: set encoding=utf-8 et sw=4 sts=4 :
 

-try:
-    import cPickle as pickle
-except ImportError:
-    import pickle
+from os import path

 
 

-from mako.template import Template
-from mako.runtime import Context
+from seqtools import Sequence
+from dispatcher import Handler, handler, HandlerError
+from services.util import Restorable, ConfigWriter
+from services.util import InitdHandler, TransactionalHandler
+
+__ALL__ = ('DhcpHandler', 'Error', 'HostError', 'HostAlreadyExistsError',
+            'HostNotFoundError', 'ParameterError', 'ParameterNotFoundError')
+
+class Error(HandlerError):
+    r"""
+    Error(message) -> Error instance :: Base DhcpHandler exception class.
+
+    All exceptions raised by the DhcpHandler inherits from this one, so you can
+    easily catch any DhcpHandler exception.
+
+    message - A descriptive error message.
+    """
+
+    def __init__(self, message):
+        r"Initialize the Error object. See class documentation for more info."
+        self.message = message
+
+    def __str__(self):
+        return self.message
+
+class HostError(Error, KeyError):
+    r"""
+    HostError(hostname) -> HostError instance
+
+    This is the base exception for all host related errors.
+    """
+
+    def __init__(self, hostname):
+        r"Initialize the object. See class documentation for more info."
+        self.message = 'Host error: "%s"' % hostname
+
+class HostAlreadyExistsError(HostError):
+    r"""
+    HostAlreadyExistsError(hostname) -> HostAlreadyExistsError instance
+
+    This exception is raised when trying to add a hostname that already exists.
+    """
+
+    def __init__(self, hostname):
+        r"Initialize the object. See class documentation for more info."
+        self.message = 'Host already exists: "%s"' % hostname
+
+class HostNotFoundError(HostError):
+    r"""
+    HostNotFoundError(hostname) -> HostNotFoundError instance
+
+    This exception is raised when trying to operate on a hostname that doesn't
+    exists.
+    """
+
+    def __init__(self, hostname):
+        r"Initialize the object. See class documentation for more info."
+        self.message = 'Host not found: "%s"' % hostname
+
+class ParameterError(Error, KeyError):
+    r"""
+    ParameterError(paramname) -> ParameterError instance
+
+    This is the base exception for all DhcpHandler parameters related errors.
+    """
+
+    def __init__(self, paramname):
+        r"Initialize the object. See class documentation for more info."
+        self.message = 'Parameter error: "%s"' % paramname
+
+class ParameterNotFoundError(ParameterError):
+    r"""
+    ParameterNotFoundError(hostname) -> ParameterNotFoundError instance
+
+    This exception is raised when trying to operate on a parameter that doesn't
+    exists.
+    """
+
+    def __init__(self, paramname):
+        r"Initialize the object. See class documentation for more info."
+        self.message = 'Parameter not found: "%s"' % paramname
+
+
+class Host(Sequence):
+    r"""Host(name, ip, mac) -> Host instance :: Class representing a host.
+
+    name - Host name, should be a fully qualified name, but no checks are done.
+    ip - IP assigned to the hostname.
+    mac - MAC address to associate to the hostname.
+    """

 
 

-class Host:

     def __init__(self, name, ip, mac):
     def __init__(self, name, ip, mac):

+        r"Initialize Host object, see class documentation for details."

         self.name = name
         self.ip = ip
         self.mac = mac
         self.name = name
         self.ip = ip
         self.mac = mac

-    def __repr__(self):
-        return 'Host(name="%s", ip="%s", mac="%s")' % (
-                     self.name, self.ip, self.mac)

 
 

-class HostHandler:
+    def as_tuple(self):
+        r"Return a tuple representing the host."
+        return (self.name, self.ip, self.mac)
+
+class HostHandler(Handler):
+    r"""HostHandler(hosts) -> HostHandler instance :: Handle a list of hosts.
+
+    This class is a helper for DhcpHandler to do all the work related to hosts
+    administration.
+
+    hosts - A dictionary with string keys (hostnames) and Host instances values.
+    """

 
     def __init__(self, hosts):
 
     def __init__(self, hosts):

+        r"Initialize HostHandler object, see class documentation for details."

         self.hosts = hosts
 
         self.hosts = hosts
 

+    @handler(u'Add a new host.')

     def add(self, name, ip, mac):
     def add(self, name, ip, mac):

-        #deberia indexar por hostname o por ip? o por mac? :)
-        # Mejor por nada...
+        r"add(name, ip, mac) -> None :: Add a host to the hosts list."
+        if name in self.hosts:
+            raise HostAlreadyExistsError(name)

         self.hosts[name] = Host(name, ip, mac)
 
         self.hosts[name] = Host(name, ip, mac)
 

+    @handler(u'Update a host.')

     def update(self, name, ip=None, mac=None):
     def update(self, name, ip=None, mac=None):

+        r"update(name[, ip[, mac]]) -> None :: Update a host of the hosts list."
+        if not name in self.hosts:
+            raise HostNotFoundError(name)

         if ip is not None:
             self.hosts[name].ip = ip
         if mac is not None:
             self.hosts[name].mac = mac
 
         if ip is not None:
             self.hosts[name].ip = ip
         if mac is not None:
             self.hosts[name].mac = mac
 

+    @handler(u'Delete a host.')

     def delete(self, name):
     def delete(self, name):

+        r"delete(name) -> None :: Delete a host of the hosts list."
+        if not name in self.hosts:
+            raise HostNotFoundError(name)

         del self.hosts[name]
 
         del self.hosts[name]
 

+    @handler(u'Get information about a host.')
+    def get(self, name):
+        r"get(name) -> Host :: List all the information of a host."
+        if not name in self.hosts:
+            raise HostNotFoundError(name)
+        return self.hosts[name]
+
+    @handler(u'List hosts.')

     def list(self):
     def list(self):

-        return ','.join(self.hosts)
+        r"list() -> tuple :: List all the hostnames."
+        return self.hosts.keys()

 
 

+    @handler(u'Get information about all hosts.')

     def show(self):
     def show(self):

-        hosts = self.hosts.values()
-        return '\n'.join('%s,%s,%s' % (h.name, h.ip, h.mac) for h in hosts)
-
-class DhcpHandler:
-    r"""class that handles DHCP service using dhcpd program"""
-
-    def __init__(self):
-        self.hosts = dict()
-        self.vars = dict(
-            domain_name = 'my_domain_name',
-            dns_1       = 'my_ns1',
-            dns_2       = 'my_ns2',
-            net_address = '192.168.0.0',
-            net_mask    = '255.255.255.0',
-            net_start   = '192.168.0.100',
-            net_end     = '192.168.0.200',
-            net_gateway = '192.168.0.1',
-        )
+        r"show() -> list of Hosts :: List all the complete hosts information."
+        return self.hosts.values()
+
+class DhcpHandler(Restorable, ConfigWriter, InitdHandler, TransactionalHandler):
+    r"""DhcpHandler([pickle_dir[, config_dir]]) -> DhcpHandler instance.
+
+    Handles DHCP service commands for the dhcpd program.
+
+    pickle_dir - Directory where to write the persistent configuration data.
+
+    config_dir - Directory where to store de generated configuration files.
+
+    Both defaults to the current working directory.
+    """
+
+    _initd_name = 'dhcpd'
+
+    _persistent_vars = ('vars', 'hosts')
+
+    _restorable_defaults = dict(
+            hosts = dict(),
+            vars  = dict(
+                domain_name = 'example.com',
+                dns_1       = 'ns1.example.com',
+                dns_2       = 'ns2.example.com',
+                net_address = '192.168.0.0',
+                net_mask    = '255.255.255.0',
+                net_start   = '192.168.0.100',
+                net_end     = '192.168.0.200',
+                net_gateway = '192.168.0.1',
+            ),
+    )
+
+    _config_writer_files = 'dhcpd.conf'
+    _config_writer_tpl_dir = path.join(path.dirname(__file__), 'templates')
+
+    def __init__(self, pickle_dir='.', config_dir='.'):
+        r"Initialize DhcpHandler object, see class documentation for details."
+        self._persistent_dir = pickle_dir
+        self._config_writer_cfg_dir = config_dir
+        self._config_build_templates()
+        self._restore()

         self.host = HostHandler(self.hosts)
 
         self.host = HostHandler(self.hosts)
 

+    def _get_config_vars(self, config_file):
+        return dict(hosts=self.hosts.values(), **self.vars)
+
+    @handler(u'Set a DHCP parameter.')

     def set(self, param, value):
     def set(self, param, value):

-        if param in self.vars:
-            self.vars[param] = value
-        else:
-            raise KeyError("Parameter " + param + " not found")
+        r"set(param, value) -> None :: Set a DHCP parameter."
+        if not param in self.vars:
+            raise ParameterNotFoundError(param)
+        self.vars[param] = value

 
 

+    @handler(u'Get a DHCP parameter.')
+    def get(self, param):
+        r"get(param) -> None :: Get a DHCP parameter."
+        if not param in self.vars:
+            raise ParameterNotFoundError(param)
+        return self.vars[param]
+
+    @handler(u'List all available DHCP parameters.')

     def list(self):
     def list(self):

-        return ','.join(self.vars)
+        r"list() -> tuple :: List all the parameter names."
+        return self.vars.keys()

 
 

+    @handler(u'Get all DHCP parameters, with their values.')

     def show(self):
     def show(self):

-        return '\n'.join(('%s,%s' % (k, v) for (k, v) in self.vars.items()))
-
-    def start(self):
-        #esto seria para poner en una interfaz
-        #y seria el hook para arrancar el servicio
-        pass
-
-    def stop(self):
-        #esto seria para poner en una interfaz
-        #y seria el hook para arrancar el servicio
-        pass
-
-    def commit(self):
-        #esto seria para poner en una interfaz
-        #y seria que hace el pickle deberia llamarse
-        #al hacerse un commit
-        pickle.dump(self.vars, file('pickled/vars.pkl', 'wb'), 2)
-        pickle.dump(self.hosts, file('pickled/hosts.pkl', 'wb'), 2)
-        tpl = Template(filename='templates/dhcpd.conf')
-        ctx = Context(file('generated/dhcpd.conf', 'w'),
-                        hosts=self.hosts.values(), **self.vars)
-        tpl.render_context(ctx)
+        r"show() -> (key, value) tuples :: List all the parameters."
+        return self.vars.items()

 
 if __name__ == '__main__':
 
 
 if __name__ == '__main__':
 

-    config = DhcpHandler()
+    import os
+
+    h = DhcpHandler()
+
+    def dump():
+        print '-' * 80
+        print 'Variables:', h.list()
+        print h.show()
+        print
+        print 'Hosts:', h.host.list()
+        print h.host.show()
+        print '-' * 80

 
 

-    config.host.add('my_name','192.168.0.102','00:12:ff:56')
+    dump()

 
 

-    config.host.update('my_name','192.168.0.192','00:12:ff:56')
+    h.host.add('my_name','192.168.0.102','00:12:ff:56')

 
 

-    config.host.add('nico','192.168.0.188','00:00:00:00')
+    h.host.update('my_name','192.168.0.192','00:12:ff:56')

 
 

-    config.set('domain_name','baryon.com.ar')
+    h.host.add('nico','192.168.0.188','00:00:00:00')
+
+    h.set('domain_name','baryon.com.ar')

 
     try:
 
     try:

-        config.set('sarasa','baryon.com.ar')
+        h.set('sarasa','baryon.com.ar')

     except KeyError, e:
         print 'Error:', e
 
     except KeyError, e:
         print 'Error:', e
 

-    config.commit()
-
-    print 'Variables:', config.list()
-    print config.show()
+    h.commit()

 
 

-    print 'Hosts:', config.host.list()
-    print config.host.show()
+    dump()

 
 

-    vars = pickle.load(file('pickled/vars.pkl'))
-    hosts = pickle.load(file('pickled/hosts.pkl'))
-    print 'Pickled vars:', vars
-    print 'Pickled hosts:', hosts
+    os.system('rm -f *.pkl ' + ' '.join(h._config_writer_files))